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Review

Natural Inhibitors of Cholinesterases: Chemistry, Structure–Activity and Methods of Their Analysis

by
Natalia Smyrska-Wieleba
and
Tomasz Mroczek
*
Department of Chemistry of Natural Products, Medical University of Lublin, 1 Chodzki Str., 20-093 Lublin, Poland
*
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2023, 24(3), 2722; https://doi.org/10.3390/ijms24032722
Submission received: 1 December 2022 / Revised: 24 January 2023 / Accepted: 26 January 2023 / Published: 1 February 2023

Abstract

:
This article aims to provide an updated description and comparison of the data currently available in the literature (from the last 15 years) on the studied natural inhibitors of cholinesterases (IChEs), namely, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). These data also apply to the likely impact of the structures of the compounds on the therapeutic effects of available and potential cholinesterase inhibitors. IChEs are hitherto known compounds with various structures, activities and origins. Additionally, multiple different methods of analysis are used to determine the cholinesterase inhibitor potency. This summary indicates that natural sources are still suitable for the discovery of new compounds with prominent pharmacological activity. It also emphasizes that further studies are needed regarding the mechanisms of action or the structure–activity correlation to discuss the issue of cholinesterase inhibitors and their medical application.

1. Introduction

Cholinesterase inhibitors are chemical compounds that impair the activity of cholinesterases: AChE and BuChE. They reduce the hydrolysis of the neurotransmitters acetylcholine (ACh) (acetylcholinesterase inhibitors) and butyrylcholine (butyrylcholinesterase inhibitors), thereby increasing their levels in the body (brain, blood and nerve tissue). Naturally occurring cholinesterase inhibitors affect esterases in a reversible manner [1].
IChE drugs currently used in medicine are synthetically derived. The majority of them originate from natural substances. One of them, tacrine, was approved for treatment, and it has been used similarly to donepezil, galanthamine (1) and rivastigmine. Unfortunately, the first of them causes hepatotoxicity, while the others have side effects including insomnia, diarrhea, nausea and vomiting [2].
IChEs (BuChE and AChE) also show therapeutic activity when applied in treatments for myasthenia gravis, myopathies, disorders associated with peripheral nerve damage, impaired conduction of nervous stimuli, and diseases associated with dementia, such as vascular dementia and Alzheimer’s and Parkinson’s diseases [3,4,5].
The mechanisms causing Alzheimer’s disease (AD) are not entirely understood. In patients with AD, marked decreases in neurotransmitter levels in the cells are observed. In particular, the concentration of acetylcholine is reduced, together with dopamine, glutamate, serotonin and norepinephrine [6].
Currently, due to the limited knowledge of effective methods of treating the causes of these disorders, therapies, as before, are mainly based on symptomatic treatments (except for Aduhelm® Aducanumab, which underwent accelerated FDA (U.S. Food and Drug Administration) approval [7]). Studies indicate that an increase in the level of cholinergic transmission in patients with AD (increase in ACh) mitigates disease progression. It also has a beneficial effect on cognitive functions and improves the patient’s mood, despite the reduction in cholinergic neurons in the brain [1,5,6]. This can be accomplished by inhibiting the hydrolytic enzyme that decomposes acetylcholine (AChE) after its release from neurons to the synaptic area. There are some studies that suggest that maintaining acetylcholine prevents the formation of senile plaques through its indirect impact on the activation of α-secretase. This is a result of the activation of protein kinase C upon stimulation by the ACh receptor muscarinic M1 [5].
AChE and BuChE can be distinguished in the central nervous system [8]. Both cholinesterases influence the distribution of ACh.
With the level of advancement of AD, the increased function of BuChE with a decrease in AChE was observed [9]. There are reports suggesting that AChE impacts the progression of dementia diseases by increasing the expression of Aβ amyloid precursor, neuronal apoptosis and the aggregation of AChE-Aβ amyloid, which is more toxic than the protein itself [1].
For the mitigation of symptoms such as a decline in cognition, listlessness and mood swings, inhibitors of BuChE may be helpful due to the presence of the enzyme observed in the structures responsible for these functions in the brain (thalamic nucleus and glia). BuChE was also present in pathological structures: senile plaques and neurofibrillary tangles in patients with AD [3,8]. During tests in normal mice, these stimulants showed an increasing tendency of ACh release in the brain. These functions are controlled by the areas of the forebrain. This can lead to the conclusion that decreasing the number of cholinergic neurons in this area can cause a disturbance in attention [10].
Potentially, it can be assumed that drugs that demonstrate the inhibition of both AChE and BuChE are preferable. It is difficult to say which substances prove to be more efficient. Certainly, we know that irreversible AChE inhibitors can cause serious toxicity and may even lead to death; hence, only reversible inhibitors are of therapeutic use [3,5].
There are also opinions in publications suggesting that compounds selectively inhibiting BuChE will be more effective than selective AChE inhibitors. These findings are based on the published results of work relating to the activity of huperzine A and the analysis of the effects of inhibitors presently used in medicine [11]. Galanthamine (1) and donepezil are reversible inhibitors of both cholinesterases (transient bonding), while rivastigmine is pseudo-irreversible (covalent bonding with the enzyme). Hence, a greater focus on selective inhibitors of BuChE is suggested [12].
The purpose of this review is to provide updated information (from the last 15 years) on cholinesterase inhibitors present in plant materials, discuss their structure–activity correlation and describe methods that can be used for their analysis. We hope that such a comprehensive review will serve as a guide for scientists willing to find potentially novel molecules for neurodegenerative disorders, such as AD.

2. Chemistry–Structure Activity

Cholinesterase inhibitors belong to different groups of compounds. It may be noted here that compounds that have shown activity generally are in similar classes and included in the same group of compounds or even the same type in the group.
Compounds of natural origin showing an inhibitory effect on cholinesterase (ChE) can be considered in terms of the potency of their activity, their selectivity for each cholinesterase or their method of binding to the enzyme (reversible, pseudo-irreversible or irreversible inhibitors) [13].
The ability to inhibit cholinesterases is observed in various groups, including alkaloids, anthranoids, bibenzyls, coumarins, chromones, diarylheptanoids, fatty acids, flavonoids, lignans, phenanthrenes, phenylpropanoids, phthalates, phenolic acids, phlorotannins, polyphenols, polyketides, steroids (sterols), terpenes (diterpenes, triterpenoids, lanostane triterpenes and sesquiterpenes (sesquiterpene lactones)), stilbenoids, triflavanones and xanthonoids.
The majority of hitherto known, applied and potent IChEs (e.g., galanthamine (1), rivastigmine and tacrine) are derived from the group of alkaloids. Additionally, flavonoids and coumarins (IBuChE) have become increasingly important as appropriate inhibitors, because they show strong inhibition of ChE and fewer side effects.
Therefore, the focus is on describing the correlation between the activity and structure of selected groups of compounds for which the results of AChE or BuChE inhibition were the most promising (Table 1) [13]. There are reports that suggest a correlation of the activity of a compound on AChE and BuChE with certain components of its structure.

2.1. Alkaloids

These metabolites are characterized by the presence of nitrogen in a negative oxidation state (proton acceptor), in most cases positioned in a heterocycle. This may affect the active site of cholinesterase [13,14].
Because of its use in therapeutics, galanthamine (1) may be considered the most important alkaloid inhibiting cholinesterases. It is applied in AD treatment or other neurological disorders. Amaryllidaceae plants are natural sources of galanthamine (1). Some species of Narcissus, Leucojum and Ungernia genera are particularly rich in this alkaloid. It can also be obtained synthetically. There were also attempts to obtain it through biosynthesis [15].
Galanthamine (1) has a strong inhibitory effect on both AChE and BuChE; however, it is more selective toward AChE. It reveals competitive inhibition; additionally, it has a modulating impact on the nicotinic acetylcholine receptor. Thanks to this effect, it also supports neuromuscular conduction [15,16,17]. There are many publications describing the inhibition of cholinesterase by galanthamine (1). Thus, it is often treated as a reference substance (Table 1). On the basis of research on the interaction between galanthamine (1) and AChE from Torpedo californica, it was found to bind in the active center of the enzyme. The interaction between the double bond present in the galanthamine (1) cyclohexene ring and Trp84 enzyme was observed [18].
Monoterpenoid indole alkaloids from Nauclea officinalis exhibit inhibitory activity against BuChE. The inhibitory impact of some of them (Table 1, Figure 1) is greater than that of galanthamine (1) [19]. Liew et al. (2015) [19], after performing molecular docking, speculate that the high value of cholinesterase inhibition exhibited by angustidine (2) is due to the hydrogen bonding (atom C-19 participates in the hydrogen bond) of the inhibitor with amino acids of the enzyme (Ser 198 and His 438) (Figure 1). On the basis of the structure–activity relationship (SAR), McNulty et al. (2010) [18] indicated that the inhibitory effect of lycorine-type alkaloids on AChE is due to an increase in the involvement of the lipophilic substituent in C-1 and C-2 acting as hydroxyl in galanthamine (1) (general structure of lycorine-type alkaloids (3)) (Figure 1).
According to Berkov et al. (2008), the alkaloids N-allyl-nor-galanthamine (4) and N-(14-methylallyl)-nor-galanthamine (5) isolated from the leaves of Leucojum aestivum L. demonstrated more potent inhibition of AChE than galanthamine (1) (Table 1). It appears that the inhibitory activity of both compounds is due to the substitution of the N-methyl derivative (allyl or 14-methylallyl group). The compounds are characterized by the presence of a methoxyl substituent at C-9, and the nitrogen atom also has a substituent alkyl group (Figure 2), which may indicate its greater lipophilicity compared to galanthamine (1) [20]. Among the alkaloids belonging to the Amaryllidaceae family (Table 1), sanguinine (6) isolated from Galanthus woronowii or Hieronymiella marginata [21,22] is the most potent. It is also substituted at the N atom but with a methyl group; however, this is the same moiety as in the case of galantamine. The stronger activity of sanguinine (6) compared to galanthamine (1), N-allyl-nor-galanthamine (4) and N-(14-methylallyl)-nor-galanthamine (5) may be explained by the presence of a hydroxyl group at the C-9 carbon and is not due to a methoxy group as in their case. The stronger the directing effect of the hydroxyl substituent (compared to the methoxy group), the stronger the activation of the aromatic ring in the electrophilic substitution reaction (Figure 2).
The structures of isoquinoline alkaloids of the protoberberine type (Table 1) are similar to the structure of acetylcholine, containing an anionic site—acetoxy—and simultaneously a cationic site (amine). As in the case of acetylcholine, this structure may enable the bonding of the acetoxy group to the serine hydroxyl group at the site of hydrolysis of the substrate located in the esteratic site of AChE. The cationic site may be an isoquinoline nitrogen atom [1]. Protoberberine-type alkaloids (e.g., berberine (7), dihydroberberine (8) and coptisine (9)) such as Amaryllidaceae alkaloids are characterized by the presence of substituent methoxy and hydroxy groups or methylenedioxy groups, but in different positions (at C-2, C-3 and C-9, C-10), as well as a positively charged nitrogen atom [23].
As noted by Song et al. (2021), the presence of a conjugated aromatic system in the B ring is responsible for the strong inhibitory activity (e.g., berberine (7), coptisine (9), epiberberine, jatrorrhizine and palmatine (Table 1)). The hydrogenation of this ring decreases the inhibitory activity of the alkaloid (e.g., dihydroberberine (8)), while the cyclization leading to the methylenedioxy group has no impact on this activity (e.g., coptisine (9)) [23] (Figure 3).
In the case of alkaloids extracted from Lycopodium casuarinoides (lycoparins A (10), B (11) and C (12)), the structure is also important in the inhibitory activity. Only lycoparin C (12) showed such an ability (Table 1), whereas lycoparins A (10) and B (11) have poor activity (IC50 > 200 µM) as a consequence of the occurrence of carboxylic acid at the C-15 and methyl substituents attached to N (Figure 4) [24].
Strong inhibitory activity against AChE comparable to that of galanthamine (1) is demonstrated by indole alkaloids from Ervatamia hainanensis (coronaridine (13) and voacangine (14)). Due to the presence of the substituent voacangine (14), they have markedly increased AChE inhibition. This is because of the attachment of the methoxyl substituent to the phenyl group, while the substitution of 10-hydroxycoronaridine with a hydroxy group on the phenyl decreases the activity (Table 1) (Figure 5) [25].

2.2. Coumarins

Coumarins are derivatives of an α-pyrone ring fused with benzene. Hydroxycoumarin (a hydroxyl group), methoxycoumarin (a methoxy group) (substituted at C-7, C-5 or less so at C-6, C-8), furanocoumarin (a furan ring) and piranocoumarin (a pyran ring) have been distinguished.
Research on the structure and inhibition led to the conclusion that furanocoumarins have more affinity for BuChE than AChE [13,14]. Cholinesterase-inhibiting coumarins are often found in the Apiaceae and Rutaceae families [26].
It is noted that the effect of compounds isolated from an extract of Citrus hystrix (6′-hydroxy-7′-methoxybergamottin (15) and 6′, 7′-dihydroxybergamottin (16)) against BuChE depends on the presence of a dioxygenated geranyl chain in their structures (Figure 6) [27].
In a study of the activity of coumarins from Angelica archangelica L., the authors assume that BuChE inhibitory activity occurs only in C-8-substituted furanocoumarins (imperatorin (17), heraclenol-2′-O-angelate (18) (Table 1)). Simple coumarins (osthole and archangelicin), 5-substituted furanocoumarins (isoimperatorin (19), phellopterin, bergapten and isopimpinellin) and substituted derivatives at both C-5 and C-8 (byakangelicin-2′-O-angelate (20) and byakangelicin-2′-O-isovalerate) do not show this effect (Figure 7) [28].
Compounds isolated from Mesua elegans such as 4-phenylcoumarins [29] show an explicit impact of inhibiting of AChE, because the activity increases for those which contain a dimethylpyran ring at C-5/C-6 and a prenyl substituent in position C-3 (mesuagenin B (21)). For 6-geranylated coumarins (5,7-dihydroxy-8-(3-methylbutanoyl)-6-[(E)-3,7-dimethylocta-2,6-dienyl]-4-phenyl-2H-chromen-2-one (22)), the activity increases in the case of the presence of a 2-methylbutanoyl group, and it is lower for those with a 2-methylpropanoyl or 3-methylbutanoyl group at C-8 (Figure 8) [29].

2.3. Diarylheptanoids

Diarylheptanoids are a group of natural compounds with structures based on a 1,7-diphenylheptane skeleton [30].
In diarylheptanoids isolated from Alpinia officinalis by Lee et al. (2018) [31] (Table 1), it has been observed that the ChE inhibition strength is related to the presence of double bonds in the molecule and is proportional to their number. Thus, (−)-alpininoid B (23) exhibits the strongest AChE and BuChE inhibition, whereas (4E)-1,7 diphenyl 4-hepten-3-one is weaker (24), and dihydroyashsbushiketol is the weakest (25), where additional bonds are absent (Figure 9) [31].

2.4. Flavonoids

Flavonoids are highly active inhibitors with low toxicity [29]. The flavonoid group consists of flavanones (27), flavonols (28), dihydroflavonols, flavones, isoflavones (29), chalcones, dihydrochalcones and aurones (Figure 10) [14].
The bond-line formula of flavonoids is made of two aromatic rings linked to diphenylpropane in a C6-C3-C6 system. Most of them have an additional gamma-pyrone system (rings C) divided into types due to the different positions of the B ring, the oxidation number of the C ring and the presence of additional functional groups [13,14,32].
Xie et al. (2014) [32] studied the link between the binding affinities of flavonoids with AChE using a typical measurement—the fluorescence quenching method reported by Ryu et al. (2012) [33]. They checked 20 flavonoids (i.e., baicalin, genistein, chrysin, apigenin, formononetin, 7,8-dihydroflavone, puerarin, luteolin, rutin (36), fisetin, naringenin, daidzein, daidzin, myricetin, myricetrin, quercetin, quercetrin, kaempferol (35), kaempferide and baicalein). According to this research, it can be inferred that inhibitory flavonoids form a complex with AChE. The presence of a hydroxyl group, especially in the A ring of the flavonoid, as well as the double bond between C-2 and C-3, increases the affinity of the enzyme (hydrogen bonds) and also increases the AChE inhibitory properties of flavonoids. Glycosylation, on the other hand, decreases the activity and affinity of flavonoids toward the enzyme in a manner that depends on the form of the attached sugar moiety (1–5-fold). The presence of a methoxy group affects the activity of a flavonoid differently depending on its type, and no correlation was observed here [32].
Analyzing the impact of the structure of flavonoids from Paulownia tomentosa fruits indicated that geranylated flavonoids at C-6 (e.g., diplacone (30)) (Table 1) are pivotal against hAChE and BuChE. The lack of this moiety causes a clear decrease in inhibition (eriodictyol (31) (IC50 = 1663 µM)). It has also been proved that dihydroflavonols (4′-O-methyldiplacol (32)) show stronger inhibition compared to flavones (4′-O-methyldiplacone (33)) (Figure 11) [34].
Selected flavonoids have been studied (docking study) (galangin (34), kaempferol (35), quercetin, myricetin, fisetin, apigenin, luteolin and rutin (36)) [35]. The inhibitory potency of flavonoids toward BuChE depends on the presence and the location of OH groups in the structure. A sugar moiety causing steric hindrance reduces these properties. Galangin (34) showed the strongest activity, kaempferol (35) was proved to be weaker, and rutin (36) was the weakest (Figure 12).

2.5. Phenanthrenes

Phenanthrenes are a group of natural compounds with a structure based on the phenanthrene skeleton, occurring in the form of monomeric, dimeric or trimeric derivatives [36].
Phenanthrenes from Bletilla striata showed potent and selective inhibitory activity against BuChE [37]. A publication by Liu et al. (2022) described that the presence of substituents at C-2 and C-7 is responsible for the stronger BuChE inhibition of phenanthrenes from Bletilla striata. The activity is more potent when the phenanthrene is substituted with a hydroxy group (e.g., 1-[(4-hydroxyphenyl)methyl]-4-methoxy-2,7-phenanthrenediol (37)), while substitution with a methoxy group reduces this effect (e.g., 1-(4-hydroxybenzyl)-4, 7-dimethoxyphenanthrene-2,8-diol (38)). Substituents at C-8 (hydroxy group) and also at C-1 (4-hydroxybenzyl) improve the affinity to the enzyme (Figure 13) [37].

2.6. Terpenes

These are compounds aggregated from properly bound isoprene subunits. We can distinguish monoterpenes, sesquiterpenes, diterpenes and triterpenes [14].
By testing acetone extracts of the roots of Salvia miltiorhiza Bunge, strong inhibitory activity against AChE for the diterpenes dihydrotanshinone I (39) (IC50 = 1 μM) and cryptotanshinone (40) (IC50 = 7 μM) and weak activity for tanshinone I (41) (IC50 > 50 μM) and tanshionone IIA (42) (IC50 > 140 μM) [38] (Table 1) were found by Ren et al. (2004). The authors suppose that the activity is probably a result of the existence of a dihydrofuran ring instead of a furan ring present in the compounds indicating weak inhibitory activity. Additionally, compounds containing an aromatic ring in their structures showed much higher activity than those that have a cyclohexane ring at this site [38]. However, the study by Zhou et al. (2011) showed quite different results [39]. Inhibitory activity was not observed in tanshinone IIA (42) or cryptotanshinone (40), but tanshinone I (41) and dihydrotanshinone I (39) showed strong activity. Both of these compounds are similar in terms of o-aromatic rings; they only differ in the presence or lack of a double bond in the furan ring. The authors suggest that for the inhibitory effect on AChE, the structure of the aromatic ring may be more important than the furan ring as was thought before (the presence or lack of a double bond) (Figure 14) [39].

2.7. Xanthonoids

Xanthonoids and xanthones are subgroups of polyphenols with structures based on the tricyclic skeleton dibenzo-γ-pirone [40].
In the study by Urbain et al. (2004), xanthones isolated from Gentiana campestris exhibited inhibitory activity against AChE [41]. Bellidifolin (43) had the best result. It achieved a minimum inhibitory quantity on TLC identical to that of galanthamine (1) (0.03 nM), while weaker results were those of bellidin (44) (0.15 nM) and its bellidifolin glycosides: 8-O-β-glucopyranoside (nor-swertianolin) and 8-O-β-glucopyranoside (swertianolin) were even weaker (0.18 and 1.2 nM, respectively) [41]. The weaker inhibition of the enzyme by glycosides can probably be explained by steric hindrance and diverted hydrophobicity. On the other hand, xanthones containing an additional methoxyl group in the C-3 position showed stronger activity [41].
In a more recent study by Urbain et al. (2008), the activity of xanthones of Gentianella amarella ssp. acuta was examined [42]. They exhibited weaker activity (also including bellidin (44) and bellidifolin (43)), and only triptexanthoside C (45) reached significant results for activity against AChE (Table 1) [42]. This compound also has a methoxyl group in its structure, which may influence the higher result of cholinesterase inhibition (Figure 15).
In summary, the potential activity of an acetylcholinesterase inhibitor is influenced by the presence of hydroxyl and methoxyl groups in the molecule and also by the presence of the cationic part of the structure of the compound (e.g., nitrogen in the heterocyclic system). The substrate-like structure of the inhibitor (or acetylcholine) indicates the competitive inhibition of the enzyme, and it is most beneficial in pharmacology. Large molecules, e.g., glycosidic forms of the tested compounds, were characterized by weaker AChE inhibitory activity due to their steric hindrance in the enzyme. The occurrence, different number and localization of double bonds, preferably in conjugated systems (diarylheptanoids and Amaryllidaceae alkaloids), are of utmost importance. With the increase in the number of conjugated double-bond systems, as well as the presence of substituents that polarize the aromatic system, the energy of the cation–π interaction increases, and thus, the binding energy of the inhibitor with the protein residue of the enzyme increases [43]. The presence of these substituents in the compounds was also significant in the inhibition against AChE. This may be related to the ability of BuChE to hydrolyze both butyrylcholine and acetylcholine [1,44]. The structure of the BuChE enzyme molecule enables the catalysis of large acyl groups, which the AChE molecule is not capable of. Hence, in the presented data (Table 1), there are many inhibitors that are inactive against AChE while demonstrating moderate or strong activity toward BuChE [1]. This may be due to the steric hindrance of the AChE enzyme due to the large branched structures of such compounds, as is demonstrated by the weaker activity of glycosides in relation to their aglycones (xanthonoids from Gentiana campestris) (Table 1).
The review topic of natural cholinesterase inhibitors has been discussed in other publications, including [45,46,47]. Most of them are based on the description of results obtained for plant fractions and extracts or, in addition, for compounds isolated from them [45,46]. This article focuses on the comparison of particular isolated natural compounds’ activities, considering both plant and animal origins (e.g., alkaloids from scorpions or sponges). Some of the previous reviews did not include this information [45,46]. The current review includes 20 groups (24 subgroups) of compounds; a total of 357 results for cholinesterase inhibition by natural compounds are listed, arranged alphabetically by compound group, species name and compound name. A total of 84 species or their varieties belonging to 44 families were examined. The current review shows, in tabular form, the results of the inhibition of both AChE and BuChE enzymes. The present summary is also characterized by the fact that the type of enzyme and the method used in the study are presented. This review shows that differences are significant and have an impact on the results of enzyme inhibition by the tested compounds. This paper focuses on the review of the results of studies on natural cholinesterase inhibitors tested using in vitro methods. The presented overview is also characterized by the description and consideration of the type of method used for the determination of cholinesterase inhibition, which has not been undertaken in other recent reviews, or they were limited to the modifications of colorimetric Ellman’s method [46].
The data, mainly from the selected latest publications issued from 2008 to 2022, on cholinesterase inhibitors of natural origin are ordered in the table below (Table 1). The following sources were used to prepare the review article database: Chemical Abstract (SciFinder), Reaxys and Science Direct (partially by authorized access), as well as sources directly obtained from the authors (ResearchGate GmbH)).
Table 1. Inhibitors’ classification in terms of their affiliation with a group of compounds, their effects on AChE and BuChE, their activity, their origins and the methods of their analysis.
Table 1. Inhibitors’ classification in terms of their affiliation with a group of compounds, their effects on AChE and BuChE, their activity, their origins and the methods of their analysis.
InhibitorsSourceActivityMethodRef.
Value of Inhibition against AChEReference Standard for AChEValue of Inhibition against BuChEReference Standard for BuChE
ALKALOIDS
Lindoldhamine isomerAbuta panurensis Eichler Menispermaceae
(branches)
39.38 ± 0.08 µM a,jNEO
3.72 ± 0.03 µM a,j
ndndMCE[48,49,50]
5-N-MethylmaytenineAbuta panurensis Eichler Menispermaceae
(branches)
19.55 ± 0.09 µM a,jNEO
3.72 ± 0.03 µM a,j
ndndMCE
N-trans-FeruloyltyramineAbuta panurensis Eichler Menispermaceae
(branches)
naNEO
3.72 ± 0.03 µM a,j
ndndMCE
PalmatineAbuta panurensis Eichler Menispermaceae
(branches)
35.25 ± 0.04 µM a,jNEO
3.72 ± 0.03 µM a,j
ndndMCE
StepharineAbuta panurensis Eichler Menispermaceae
(branches)
61.24 ± 0.03 µM a,jNEO
3.72 ± 0.03 µM a,j
ndndMCE
AconorineAconitum laeve
Ranunculaceae
(tubers)
2.51 ± 0.037 µM a,eGAL
3.26 ± 0.021 µM a,e
8.72 ± 0.023 µM a,mGAL
10.13 ± 0.05 µM a,m
MCE[51,52]
HohenackerineAconitum laeve
Ranunculaceae
(tubers)
4.53 ± 0.062 µM a,eGAL
3.26 ± 0.021 µM a,e
9.94 ± 0.073 µM a,mGAL
10.13 ± 0.05 µM a,m
MCE
LappaconotineAconitum laeve
Ranunculaceae
(tubers)
6.13 ± 0.019 µM a,eGAL
3.26 ± 0.021 µM a,e
11.24 ± 0.12 µM a,mGAL
10.13 ± 0.05 µM a,m
MCE
Swatinine-CAconitum laeve
Ranunculaceae
(tubers)
3.7 ± 0.085 µM a,eGAL
3.26 ± 0.021 µM a,e
12.23 ± 0.014 µM a,mGAL
10.13 ± 0.05 µM a,m
MCE
4-Methoxy-1-methyl-2-quinoloneAtractylis cancellata L.
Asteraceae
(whole plant)
>50 µg mL−1 a,kGAL
6.27 ± 1.15 µg mL−1 a,k
37.49 ± 1.61 µg mL−1 a,nGAL
34.75 ± 1.99 µg mL−1 a,n
MCE[53]
Pyrroloquinolone AAtractylis cancellata L.
Asteraceae
(whole plant)
18.48 ± 0.33 µg mL−1 a,kGAL
6.27 ± 1.15 µg mL−1 a,k
9.66 ± 0.16 µg mL−1 a,nGAL
34.75 ± 1.99 µg mL−1 a,n
MCE
Buthutin AButhus martensii Karsch
Buthidae
(whole body of scorpion)
7.83 ± 0.06 µM a,eGAL
1.17 ± 0.01 µM a,e
DON
0.049 ± 0.004 µM a,e
47.44 ± 0.95 µM a,mGAL
18.78 ± 1.81 µM a,m
DON
5.536± 0.018 µM a,m
MCE[48,54,55]
Buthutin BButhus martensii Karsch
Buthidae
(whole body of scorpion)
61.45 ± 2.34 µM a,eGAL
1.17 ± 0.01 µM a,e
DON
0.049 ± 0.004 µM a,e
122.64 ± 5.21 µM a,mGAL
18.78 ± 1.81 µM a,m
DON
5.536± 0.018 µM a,i
MCE
TrigonellineButhus martensii Karsch
Buthidae
(whole body of scorpion)
97.30 ± 4.18 µM a,eGAL
1.17 ± 0.01 µM a,e
DON
0.049 ± 0.004 µM a,e
441.87 ± 7.99 µM a,mGAL
18.78 ± 1.81 µM a,m
DON
5.536± 0.018 µM a,m
MCE
17-oxo-3-BenzoylbuxadineBuxus hyrcana Pojark.
Buxaceae
(leaves)
17.6 ± 0.5 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
186.8 ± 1.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE[48,56,57,58]
31-DemethylcyclobuxoviridineBuxus hyrcana Pojark.
Buxaceae
(leaves)
298.3 ± 1.0 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
15.4 ± 0.5 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
31-Hydroxybuxamine BBuxus hyrcana Pojark.
Buxaceae
(leaves)
61.3 ± 2.0 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
112.1 ± 3.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
Buxamine ABuxus hyrcana Pojark.
Buxaceae
(leaves)
81.4 ± 2.4 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
100.2 ± 1.4 µM a,nGAL
8.7 ± 1.0 µM a,n HUP
>1000 ± 3.0 µM a,n
MCE
Buxamine BBuxus hyrcana Pojark.
Buxaceae
(leaves)
79.6 ± 3.0 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
100.5 ± 2.5 µM a,kGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
Buxhyrcamine Buxus hyrcana Pojark.
Buxaceae
(leaves)
18.2 ± 0.3 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
209.0 ± 1.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
Buxmicrophylline FBuxus hyrcana Pojark.
Buxaceae
(leaves)
22.4 ± 0.7 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
154.2 ± 1.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
BuxrugulosamineBuxus hyrcana Pojark.
Buxaceae
(leaves)
24.8 ± 1.0 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
160.2 ± 4.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
Cyclobuxophylline OBuxus hyrcana Pojark.
Buxaceae
(leaves)
35.4 ± 1.0 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
45.0 ± 2.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
CyclobuxoviridineBuxus hyrcana Pojark.
Buxaceae
(leaves)
179.7 ± 0.4 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
304.5 ± 1.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
E-BuxenoneBuxus hyrcana Pojark.
Buxaceae
(leaves)
71.0 ± 2.5 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
200.7 ± 2.6 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
HomomoenjodarmineBuxus hyrcana Pojark.
Buxaceae
(leaves)
19.5 ± 1.0 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
52.2 ± 3.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
MoenjodaramineBuxus hyrcana Pojark.
Buxaceae
(leaves)
25.0 ± 2.9 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
102.4 ± 2.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
Nb-DimethylcyclobuxoviricineBuxus hyrcana Pojark.
Buxaceae
(leaves)
45.5 ± 0.6 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
133.8 ± 3.4 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
N20-Formylbuxaminol EBuxus hyrcana Pojark.
Buxaceae
(leaves)
25.5 ± 0.8 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
120.9 ± 2.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
SpirofornabuxineBuxus hyrcana Pojark.
Buxaceae
(leaves)
6.3 ± 0.6 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
125.2 ± 1.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE
Papillozine CBuxus hyrcana Pojark.
Buxaceae
(leaves)
47.8 ± 1.4 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
35.2 ± 2.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM µM a,n
MCE
Z-BuxenoneBuxus hyrcana Pojark.
Buxaceae
(leaves)
87.4 ± 1.7 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
155.8 ± 3.8 µM a,nGAL
8.7 ± 1.0 µM µM a,n
HUP
>1000 ± 3.0 µM µM a,n
MCE
DihydroberberineCoptis chinensis
Ranunculaceae
(rhizomes)
1.18 ± 0.03 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
38.82 ± 0.52 µM a,mTAC
0.014 ± 0.0043 µM a,m
MCE[48,59,60]
10-Hydroxy-infractopicrinCortinarius infractus Berk
Cortinariaceae
(toadstool)
12.7 ± 0.16 µM a,dGAL
8.70 ± 0.05 µM a,d
PHY
2.58 ± 0.03 µM a,d
nd < 100 µM a,mGAL
24.4 ± 2.84 µM a,m
PHY
1.34 ± 0.279 µM a,m
MCE[16,48,61]
InfractopicrinCortinarius infractus Berk
Cortinariaceae
(toadstool)
9.72 ± 0.19 µM a,dGAL
8.70 ± 0.05 µM a,d
PHY
2.58 ± 0.03 µM a,d
nd < 100 µM a,mGAL
24.4 ± 2.84 µM a,m
PHY
1.34 ± 0.279 µM a,m
MCE
(+)-AdlumineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE[16,48,62,63]
BicucullinineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
85.89 ± 0.92 µM a,eGAL
1.34 ± 0.11 µM a,e
59.75 ± 2.40 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
(−)-CorydalisolCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
51.12 ± 0.27 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
DemethylcorydalmineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
71.43 ± 0.55 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
6,7-Dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinolineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
45.70 ± 0.42 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
1-(1,3-Dioxolo [4,5-g]isoquinolin-5-yl)-ethanone Corydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
epi-CoryximineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
92.00 ± 0.19 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
Hendersine BCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
14.22 ± 0.34 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
HydrohydrastinineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
9.13 ± 0.15 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
9-Methyldecumbenine CCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
Mucroniferanines HCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
2.31 ± 0.20 µM a,eGAL
1.34 ± 0.11 µM a,e
36.71 ± 1.12 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
Mucroniferanines KCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
Mucroniferanines LCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
Mucroniferanines MCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
(+)-OchotensineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
(−)-OchrobirineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
OrientalineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
83.96 ± 1.06 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
1R,9S,7′S-MethylegenineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
5,6,7,8-Tetrahydro-1,3-dioxolo [4,5-g]isoquinolineCorydalis mucronifera Maxim.
Papaveraceae
(whole plants)
>100 µM a,eGAL
1.34 ± 0.11 µM a,e
>100 µM a,mGAL
6.81 ± 0.60 µM a,m
MCE
PseudocoptisineCorydalis turtschaninovii
Besser forma yanhusuo Papaveraceae (tuber)
12.8 µM a,iTAC
0,175 µM a,i
ndndMCE[64]
(−)-DesmethylsecoantofineCryptocarya densiflora BI.
Lauraceae
(leaves)
201.52 µM a,ePHY
0.16 µM a,e
166.69 µM a,mPHY
0.58 µM a,m
MCE[48,65,66]
(+)-LaurotetanineCryptocarya densiflora BI.
Lauraceae
(leaves)
100 µg mL−1—17.51 ± 0.68% b,end100 µg mL−1—22.58 ± 0.47 µM a,mPHY
0.58 µM a,m
MCE
(+)-nor-NantenineCryptocarya densiflora BI.
Lauraceae
(leaves)
205.55 µM a,ePHY
0.16 µM a,e
94.45 µM a,mPHY
0.58 µM a,m
MCE
(+)-OridineCryptocarya densiflora BI.
Lauraceae
(leaves)
100 µg mL−1—27.89 ± 0.64% b,end288.34 µM a,mPHY
0.58 µM a,m
MCE
2-MethoxyatherosperminineCryptocarya griffithiana Wight.
Lauraceae
(bark)
100 µg mL−1—31.58 ± 2.87% b,end3.95 µM a,mPHY
0.58 µM a,m
MCE
(+)-ReticulineCryptocarya griffithiana Wight.
Lauraceae
(bark)
301.01 µM a,ePHY
0.16 µM a,e
65.04 µM a,mPHY
0.58 µM a,m
MCE
AtherosperminineCryptocarya infectoria Miq.
Lauraceae
(bark)
100 µg mL−1—2.06 ± 1.29% b,end19.34 µM a,mPHY
0.58 µM a,m
MCE
(+)-N-MethylisococlaurineCryptocarya infectoria Miq.
Lauraceae
(bark)
100 µg mL−1—14.93 ± 0.53% b,end100 µg mL−1—37.33 ± 1.56 a,mPHY
0.58 µM a,m
MCE
(+)-N-MethyllaurotetanineCryptocarya infectoria Miq.
Lauraceae
(bark)
100 µg mL−1—38.79 ± 2.6% b,end218.81 µM a,mPHY
0.58 µM a,m
MCE
Chitralinine A Delphinium chitralense H. Riedl in Kew Bull. Ranunculaceae
(aerial parts)
13.86 ± 0.35 µM a,eGAL
10.12 ± 0.06 µM a,e
ALA
8.23 ± 0.01 µM a,e
28.17 ± 0.92 µM a,mGAL
20.62 ± 0.08 µM a,m
ALA
18 ± 0.06 µM a,m
MCE[48,67]
Chitralinine B Delphinium chitralense H. Riedl in Kew Bull. Ranunculaceae
(aerial parts)
11.64 ± 0.08 µM a,eGAL
10.12 ± 0.06 µM a,e
ALA
8.23 ± 0.01 µM a,e
24.31 ± 0.33 µM a,mGAL
20.62 ± 0.08 µM a,m
ALA
18 ± 0.06 µM a,m
MCE
Chitralinine C Delphinium chitralense H. Riedl in Kew Bull. Ranunculaceae
(aerial parts)
12.11 ± 0.82 µM a,eGAL
10.12 ± 0.06 µM a,e
ALA
8.23 ± 0.01 µM a,e
26.35 ± 0.06 µM a,mGAL
20.62 ± 0.08 µM a,m
ALA
18 ± 0.06 µM a,m
MCE
DihydropentagynineDelphinium denudatum
Ranunculaceae
(aerial parts)
11.2 ± 0.23 µM a,eGAL
10.1 ± 0.06 µM a,e
22.2 ± 0.33 µM a,mGAL
20.6 ± 0.08 µM a,m
MCE[51,68]
Isotalatizidine hydrate Delphinium denudatum
Ranunculaceae
(aerial parts)
12.1 ± 0.43 µM a,eGAL
10.1 ± 0.06 µM a,e
21.4 ± 0.23 µM a,mGAL
20.6 ± 0.08 µM a,m
MCE
Jadwarine-ADelphinium denudatum
Ranunculaceae
(aerial parts)
9.2 ± 0.12 µM a,eGAL
10.1 ± 0.06 µM a,e
19.6 ± 0.72 µM a,mGAL
20.6 ± 0.08 µM a,m
MCE
CoronaridineErvatamia hainanensis Tsiang
Apocynaceae
(stems)
8.6 µM a,eGAL
3.2 µM a,e
ndndCE[25,48]
VoacangineErvatamia hainanensis Tsiang
Apocynaceae
(stems)
4.4 µM a,eGAL
3.2 µM a,e
ndndCE
1-O-Acetyl-9-O-methylpseudolycorineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
78.7 µM a,fGAL
0.15 µM a,f
ndndMCE[21,48,69]
GalanthineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
7.75 µM a,fGAL
0.15 µM a,f
ndndMCE
LycorineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
naGAL
0.15 µM a,f
ndndMCE
NarwedineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
11,79 µM a,fGAL
0.15 µM a,f
ndndMCE
O-MethylleucotamineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
16.42 µM a,fGAL
0.15 µM a,f
ndndMCE
SalsolineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
naGAL
0.15 µM a,f
ndndMCE
SanguinineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
0.007 µM a,fGAL
0.15 µM a,f
ndndMCE
SternbergineGalanthus woronowii Losinsk
Amaryllidaceae
(aerial parts and bulbs)
0.99 µM a,fGAL
0.15 µM a,f
ndndMCE
ChlidanthineHieronymiella marginata
Hunz
Amaryllidaceae
(bulbs)
23.50 ± 0.65 µM a,eGAL
1 ± 0.05 µM a,e
196.79 ± 2.67 µM a,mGAL
14 ± 0.03 µM a,m
MCE[22,48,70]
LycorineHieronymiella marginata
Hunz
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
1 ± 0.05 µM a,e
>200 µM a,mGAL
14 ± 0.03 µM a,m
MCE
SanguinineHieronymiella marginata
Hunz
Amaryllidaceae
(bulbs)
0.10 ± 0.03 µM a,eGAL
1 ± 0.05 µM a,e
21.50 ± 0.04 µM a,mGAL
14 ± 0.03 µM a,m
MCE
TazettineHieronymiella marginata
Hunz
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
1 ± 0.05 µM a,e
>200 µM a,mGAL
14 ± 0.03 µM a,m
MCE
HamayneHippeastrum argentinum Pax
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
0.48 ± 0.03 µM a,e
>200 µM a,mGAL
22.39 ± 0.09 µM a,m
MCE[48,69,70]
7-HydroxyclivonineHippeastrum argentinum Pax
Amaryllidaceae
(bulbs)
114.07 ± 0.08 µM a,eGAL
0.48 ± 0.03 µM a,e
67.3 ± 0.09 µM a,mGAL
22.39 ± 0.09 µM a,m
MCE
LycorineHippeastrum argentinum Pax
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
0.48 ± 0.03 µM a,e
>200 µM a,mGAL
22.39 ± 0.09 µM a,m
MCE
4-O-MethylnangustineHippeastrum argentinum Pax
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
0.48 ± 0.03 µM a,e
>200 µM a,mGAL
22.39 ± 0.09 µM a,m
MCE
MontanineHippeastrum argentinum Pax
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
0.48 ± 0.03 µM a,e
>200 µM a,mGAL
22.39 ± 0.09 µM a,m
MCE
PancracineHippeastrum argentinum Pax
Amaryllidaceae
(bulbs)
>200 µM a,eGAL
0.48 ± 0.03 µM a,e
>200 µM a,mGAL
22.39 ± 0.09 µM a,m
MCE
Discorhabdin CLatrunculia biformis
Latrunculiidae
(sponge)
14.5 ± 1.5 µM a,e
152 ± 12 µM a,f
PHY
3.0 ± 0.3 µM a,e
PHY
14.5 ± 2.0 µM a,f
15.8 ± 3.5 µM a,mPHY
28.5 ± 3.0 µM a,m
MCE[48,71]
Discorhabdin GLatrunculia biformis
Latrunculiidae
(sponge)
1.3 ± 0.2 µM a,e
116 ± 9 µM a,f
PHY
3.0 ± 0.3 µM a,e
PHY
14.5 ± 2.0 µM a,f
7.0 ± 1.0 µM a,mPHY
28.5 ± 3.0 µM a,m
MCE
Discorhabdin BLatrunculia bocagei
Latrunculiidae
(sponge)
5.7 ± 0.8 µM a,e
49.4 ± 7.5 µM a,f
PHY
3.0 ± 0.3 µM a,e
PHY
14.5 ± 2.0 µM a,f
137 ± 14.5 µM a,mPHY
28.5 ± 3.0 µM a,m
MCE
Discorhabdin LLatrunculia bocagei
Latrunculiidae
(sponge)
25.7 ± 3.0 µM a,e
158 ± 15 µM a,f
PHY
3.0 ± 0.3 µM a,e
PHY
14.5 ± 2.0 µM a,f
531 ± 45.0 µM a,mPHY
28.5 ± 3.0 µM a,m
MCE
LupanineLeontice leontopetalum L.
subsp. ewersmannii.
Berberidaceae
(tubers)
200 µg/µL—35.41 ± 3.55% b,kGAL
200 µg/µL—89.98 ± 0.61% b,k
200 µg/µL—81.77 ± 2.41% b,nGAL
200 µg/µL—92.47 ± 0.63% b,n
CE[48,72]
N-(14-Methylallyl)-nor-galanthamineLeucojum aestivum L.
Amaryllidaceae
(aerial parts)
0.16 ± 0.01 µM a,eGAL
1.82 ± 0.40 µM a,e
ndndMCE[20,69]
N-Allyl-nor-galanthamineLeucojum aestivum L.
Amaryllidaceae
(aerial parts)
0.18 ± 0.01 µM a,eGAL
1.82 ± 0.40 µM a,e
ndndMCE
Casuarinine CLycopodiastrum casuarinoides Spring
Lycopodiaceae
(whole plant)
20.9 µM a,iHUP
0.125 µM a,i
ndndMCE[48,73]
Casuarinine ILycopodiastrum casuarinoides Spring
Lycopodiaceae
(whole plant)
12.1 µM a,iHUP
0.125 µM a,i
ndndMCE
N-DemethylhuperzinineLycopodiastrum casuarinoides Spring
Lycopodiaceae
(whole plant)
15.0 µM a,iHUP
0.125 µM a,i
ndndMCE
Huperzine C
Lycopodiastrum casuarinoides Spring
Lycopodiaceae
(whole plant)
0.489 µM a,iHUP
0.125 µM a,i
ndndMCE
Lycoparin CLycopodium
casuarinoides Spring
Lycopodiaceae
(whole plant)
25 µM a,kndndndCE[24,48]
Serratezomine DLycopodium serratum Thunb. var. serratum
Lycopodiaceae
(whole plant)
0.6 mM a,eGAL
6.4 µM a,e
ndndCE[48,74]
BerberineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
0.52 ± 0.06 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE[23,48,75]
CoptisineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
0.53 ± 0.04 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
CorypalmineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
130.10 ± 9.81 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
DihydroberberineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
7.33 ± 0.47 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE[23,48,75]
EpiberberineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
0.80 ± 0.15 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
JatrorrhizineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
0.51 ± 0.04 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
PalmatineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
0.74 ± 0.13 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
StylopineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
5.07 ± 0.16 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
TetrahydroberberineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
13.13 ± 0.4 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
TetrahydropalmatineMahonia bealei Carrière,
Mahonia fortunei Fedde Berberidaceae
(root, stem, leaf)
47.56 ± 1.46 µM a,kGAL
0.81 ± 0.08 µM a,k
ndndMCE
MahanimbineMurraya koenigii L.
Rutaceae
(leaves)
0.03 ± 0.09 mg mL−1 a,dGAL
0.006 ± 0.001 mg mL−1 a,d
ndndMCE[48,76]
1,2-DihydrogalanthamineNarcissus jonquilla ‘Pipit’
Amaryllidaceae
(bulbs)
0.19 µM a,eGAL
0.27 µM a,e
ndndBTLC
by Mroczek
[77]
HaemanthamineNarcissus poeticus ‘Pink Parasol’
Amaryllidaceae
(bulbs)
>500 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE[48,78]
HippeastrineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
>500 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
HomolycorineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
64 ± 4 µM a,fGAL
1.7 ± 0.1µM a,f
HUP
0.033 ± 0.001µM a,f
151 ± 19 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
IncartineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
208 ± 14 µM a,fGAL
1.7 ± 0.1µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
LycoramineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
456 ± 57 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
MasonineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
304 ± 34 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
229 ± 24 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
NarcipavlineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
208 ± 37 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
24.4 ± 1.2 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
NarwedineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
281 ± 33 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
nor-LycoramineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
>500 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
OdulineNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
>500 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
seco-IsopowellaminoneNarcissus poeticus ‘Pink Parasol
Amaryllidaceae
(bulbs)
293 ± 33 µM a,fGAL
1.7 ± 0.1 µM a,f
HUP
0.033 ± 0.001 µM a,f
>500 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>500 µM a,l
MCE
IncartineNarcissus jonquila var. henriquesii Samp.
Amaryllidaceae
(bulbs)
208.2 ± 14.3 µM a,fGAL
1.7 ± 0.06 µM a,f
HUP
0.03 ± 0.0 µM a,f
PHY
0.06 ± 0.0 µM a,f
943.4 ± 140.7 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>1000 µM a,l
PHY
0.13 ± 0.0 µM a,l
MCE[48,79]
NarwedineNarcissus poeticus ’Brackenhurst’
Amaryllidaceae
(bulbs)
281.2 ± 33.9 µM a,fGAL
1.7 ± 0.06 µM a,f
HUP
0.03 ± 0.0 µM a,f
PHY
0.06 ± 0.0 µM a,f
911.3 ± 68.7 µM a,lGAL
42.3 ± 1.3 µM a,l
HUP
>1000 µM a,l
PHY
0.13 ± 0.0 µM a,l
MCE
11-HydroxygalanthineNarcissus tazetta subsp. tazetta L
Amaryllidaceae
(bulbs
and leaves)
0.67 µM a,eGAL
0.15 µM a,e
18.17 µM a,mGAL
2.47µM a,m
MCE[48,80]
9-O-Demetil-2-α-hydroxyhomolycorineNarcissus tazetta subsp. tazetta L
Amaryllidaceae
(bulbs
and leaves)
19.84 µM a,eGAL
0.15 µM a,e
naGAL
2.47 µM a,m
MCE
NarcissidineNarcissus tazetta subsp. tazetta L
Amaryllidaceae
(bulbs
and leaves)
1.85 µM a,eGAL
0.15 µM a,e
naGAL
2.47 µM a,m
MCE
Pancratinine-CNarcissus tazetta subsp. tazetta L
Amaryllidaceae
(bulbs
and leaves)
naGAL
0.15 µM a,e
32.04 µM a,mGAL
2.47 µM a,m
MCE
PseudolycorineNarcissus tazetta subsp. tazetta L
Amaryllidaceae
(bulbs
and leaves)
32.51 µM a,eGAL
0.15 µM a,e
21.64 µM a,mGAL
2.47 µM a,m
MCE
AngustidineNauclea officinalis Merr. & Chun.
Rubiaceae
(bark)
21.72 µM a,eGAL
0.94 µM a,e
1.03 µM a,mGAL
28.29 µM a,m
CE[19,48,81]
AngustineNauclea officinalis Merr. & Chun.
Rubiaceae
(bark)
100 μg mL−1—40.19 ± 0.65% b,eGAL
0.94 µM a,e
4.98 µM a,mGAL
28.29 µM a,m
CE
AngustolineNauclea officinalis Merr. & Chun.
Rubiaceae
(bark)
261.89 µM a,eGAL
0.94 µM a,e
25.10 µM a,mGAL
28.29 µM a,m
CE
HarmaneNauclea officinalis Merr. & Chun.
Rubiaceae
(bark)
300.68 µM a,eGAL
0.94 µM a,e
13.18 µM a,mGAL
28.29 µM a,m
CE
NauclefineNauclea officinalis Merr. & Chun.
Rubiaceae
(bark)
100 μg mL−1—34.61 ± 4.84% b,eGAL
0.94 µM a,e
7.70 µM a,mGAL
28.29 µM a,m
CE
7,8,13,14-DehydroorientalidinePapaver setiferum Goldblatt
Papaveraceae
(capsules)
ndNEO
6.0 ± 1.1 µM a,e
ndNEO
92.7 ± 2.2 µM a,m
MCE[48,82,83]
7,8-Didehydromecambridine TFA saltPapaver setiferum Goldblatt
Papaveraceae
(capsules)
10.3 ± 1.1 µM a,eNEO
6.0 ± 1.1 µM a,e
100 ± 5 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
7,8-
Didehydroorientalidine TFA salt
Papaver setiferum Goldblatt
Papaveraceae
(capsules)
3.4 ± 4.7 µM a,eNEO
6.0 ± 1.1 µM a,e
98.5 ± 0.6 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
AlborinePapaver setiferum Goldblatt
Papaveraceae
(capsules)
6.8 ± 4.5 µM a,eNEO
6.0 ± 1.1 µM a,e
63.1 ± 0.5 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
IsothebainePapaver setiferum Goldblatt
Papaveraceae
(capsules)
260 ± 1 µM a,eNEO
6.0 ± 1.1 µM a,e
2.8 ± 3.0 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
N-MethylcodaminePapaver setiferum Goldblatt
Papaveraceae
(capsules)
ndNEO
6.0 ± 1.1 µM a,e
221 ± 1 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
N-MethylisothebainiumPapaver setiferum Goldblatt
Papaveraceae
(capsules)
ndNEO
6.0 ± 1.1 µM a,e
7.1 ± 2.7 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
N-MethylorientalinePapaver setiferum Goldblatt
Papaveraceae
(capsules)
ndNEO
6.0 ± 1.1 µM a,e
342 ± 3 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
OrientalidinePapaver setiferum Goldblatt
Papaveraceae
(capsules)
5.0 ± 1.0 µM a,eNEO
6.0 ± 1.1 µM a,e
104 ± 4 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
SalutaridinePapaver setiferum Goldblatt
Papaveraceae
(capsules)
ndNEO
6.0 ± 1.1 µM a,e
335 ± 4 µM a,mNEO
92.7 ± 2.2 µM a,m
MCE
19(S)-HydroxyibogamineTabernaemontana bufalina Lour.
(Apocynaceae)
ndnd20.1 µM a,mTAC
0.025 µM a,m
MCE[48,84,85]
3α-DihydrocadambineUncaria rhynchophylla Miq. ex Havil
Rubiaceae
(stems)
37.01 ± 1.57 µM a,eTAC
4.39 ± 0.80 µM a,e
33.34 ± 0.51 µM a,mTAC
3.25 ± 1.86 µM a,m
MCE[48,86]
7-epi-JavanisideUncaria rhynchophylla Miq. ex Havil
Rubiaceae
(stems)
2.85 ± 0.50 µM a,eTAC
4.39 ± 0.80 µM a,e
2.13 ± 0.10 µM a,mTAC
3.25 ± 1.86 µM a,m
MCE
CadambineUncaria rhynchophylla Miq. ex Havil
Rubiaceae
(stems)
26.12 ± 2.12 µM a,eTAC
4.39 ± 0.80 µM a,e
30.69 ± 0.69 µM a,mTAC
3.25 ± 1.86 µM a,m
MCE
StrictosamideUncaria rhynchophylla Miq. ex Havil
Rubiaceae
(stems)
46.57 ± 0.58µM a,eTAC
4.39 ± 0.80 µM a,e
6.47 ± 0.72 µM a,mTAC
3.25 ± 1.86 µM a,m
MCE
VincosamideUncaria rhynchophylla Miq. ex Havil
Rubiaceae
(stems)
12.4 ± 0.86 µM a,eTAC
4.39 ± 0.80 µM a,e
23.18 ± 0.14 µM a,mTAC
3.25 ± 1.86 µM a,m
MCE
Deoxyvobtusine lactoneVoacanga globosa Merr.
Apocynaceae
(leaves)
10−4.3 M—91% b,eGAL
0.64 µM a,e
20.2 µM a,mGAL
8.40 µM a,m
MCE[87,88,89]
DeoxyvobtusineVoacanga globosa Merr.
Apocynaceae
(leaves)
10−4.3 M—87% b,eGAL
0.64 µM a,e
6.2 µM a,mGAL
8.40 µM a,m
MCE
GlobospiramineVoacanga globosa Merr.
Apocynaceae
(leaves)
10−4.3 M—94% b,eGAL
0.64 µM a,e
16.4 µM a,mGAL
8.40 µM a,m
MCE
Vobtusine
lactone
Voacanga globosa Merr.
Apocynaceae
(leaves)
10−4.3 M—90% b,eGAL
0.64 µM a,e
18.0 µM a,mGAL
8.40 µM a,m
MCE
ANTHRANOIDS
2-GeranylemodinPsorospermum glaberrimum Hochr.
Hypericaceae
(stem bark)
0.1 mM—12.9% b,eGAL
0.50 ± 0.001 µM a,e
11.30 ± 0.23 µM a,mGAL
8.50 ± 0.001 µM a,m
MCE[48,90]
3-PrenyloxyemodinPsorospermum glaberrimum Hochr.
Hypericaceae
(stem bark)
0.1 mM—35.0% b,eGAL
0.50 ± 0.001 µM a,e
13.3 ± 1.10 µM a,mGAL
8.50 ± 0.001 µM a,m
MCE
Acetylvismione DPsorospermum glaberrimum Hochr.
Hypericaceae
(stem bark)
0.1 mM—45.70% b,eGAL
0.50 ± 0.001 µM a,e e
10.1 ± 0.20 µM a,mGAL
8.50 ± 0.001 µM a,m
MCE
Bianthrone 1aPsorospermum glaberrimum Hochr.
Hypericaceae
(stem bark)
63.0 ± 0.46 µM a,eGAL
0.50 ± 0.001 µM a,e a,e
9.25 ± 0.25 µM a,mGAL
8.50 ± 0.001 µM a,m
MCE
3-Geranyloxyemodin anthronePsorospermum glaberrimum Hochr.
Hypericaceae
(stem bark)
100 µM—5.4% b,eGAL
0.50 ± 0.001 µM a,e e
11.60 ± 0,20 µM a,mGAL
8.50 ± 0.001 µM a,m
MCE
3-Prenyloxyemodin anthronePsorospermum glaberrimum Hochr.
Hypericaceae
(stem bark)
100 µM—13.8% b,eGAL
0.50 ± 0.001 µM a,e
10.1 ± 0.5 µM a,mGAL
8.50 ± 0.001 µM a,m
MCE
EmodinTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
>100 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e
>100 µM a,mndMCE[48,91,92]
PhyscionTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
>100 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e
>100 µM a,mndMCE
ChrysophanolTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
>100 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e,
>100 µM a,mndMCE
BIBENZYLS
3,3′-Dihydroxy-4-(4-hydroxybenzyl)-5-methoxybibenzylBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—2.6 ± 2.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—22.6 ± 2.1% b,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE[37,48]
3′,5-Dihydroxy-2-(4-hydroxybenzyl)-3-methoxybibenzyl Bletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—5.0 ± 1.5% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—51.3 ± 2.0% b,m
80.3 ± 5.2 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
BulbocolBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—16.3 ± 3.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—67.7 ± 0.3% b,m
33.5 ± 3.7 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Gymconopin D Bletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—48.1 ± 6.3% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—66.2 ± 3.4% b,m
40.5 ± 5.6 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
COUMARINS
ScopoletinScopolia carniolica Jaqc.
Solanaceae
(roots)
168.6 µM a,eGAL
3.2 µM a,e
ndndMCE[16,48,93,94,95]
DecursinolAngelica gigas Nakai
Apiaceae
(underground parts)
28 μM a,kndndndMCE[48,96,97,98]
IsoimperatorinAngelica gigas Nakai
Apiaceae
(underground parts)
69 μM a,kndndndMCE
MarmesinAngelica gigas Nakai
Apiaceae
(underground parts)
67 μM a,kndndndMCE
NodakeninAngelica gigas Nakai
Apiaceae
(underground parts)
68 μM a,kndndndMCE
XanthotoxinAngelica gigas Nakai
Apiaceae
(underground parts)
54 μM a,kndndndMCE
BergaptenAngelica officinalis L.
Apiaceae
(fruits)
25 µg mL−1
32.65 ± 6.10% b,e
100 µg mL−1—nd
GAL
100 µg mL−1—98.97 ± 0.24% b,e
25 µg mL−1—86.69 ± 2.56% b,m
100 µg mL−1- nd
GAL
100 µg mL−1—80.31 ± 1.14% b,m
MCE[48,99,100]
ImperatorinAngelica officinalis L.
Apiaceae
(fruits)
25 µg mL−1
18.76 ± 1.07% b,e
100 µg mL−1—46.11 ± 0.92% b,e
GAL
100 µg mL−1—98.97 ± 0.24% b,e
25 µg mL−1
37.46 ± 1.09% b,m
100 µg mL−1
83.98 ± 0.99% b,m
GAL
100 µg mL−1—80.31 ± 1.14% b,m
MCE
XanthotoxinAngelica officinalis L.
Apiaceae
(fruits)
25 µg mL−1
38.23 ± 0.06% b,e
100 µg mL−1—66.08 ± 2.88% b,e
GAL
100 µg mL−1—98.97 ± 0.24% b,e
25 µg mL−1—63.60 ± 1.78% b,m
100 µg mL−1—88.04 ± 0.83% b,m
GAL
100 µg mL−1—80.31 ± 1.14% b,m
MCE
Heraclenol-2′-O-angelateArchangelicae officinalis L.
Apiaceae
(roots)
>1000 μM a,eGAL
0.37 ± 1.1 μM a,e
7.5 ± 1.8 μM a,mGAL
8.3 ± 2.6 μM a,m
BTLC
by Marston et al. (2002)
[28,48,101]
ImperatorinArchangelicae officinalis L.
Apiaceae
(fruits)
156 ± 15 μM a,eGAL
0.37 ± 1.1 μM a,e
14.4 ± 3.2 μM a,mGAL
8.3 ± 2.6 μM a,m
BTLC
by Marston et al. (2002)
IsoimperatorinCitrus hystrix DC.
Rutaceae
(peels of fruits)
ndnd23 ± 0.2 µM a,mGAL
3.2 ± 0.2 µM a,m
MCE[27,48]
6′,7′-
Dihydroxybergamottin
Citrus hystrix DC
Rutaceae
(peels of fruits)
ndnd15.4 ± 0.3 µM a,mGAL
3.2 ± 0.2 µM a,m
MCE
6′-Hydroxy-7′-methoxybergamottinCitrus hystrix DC.
Rutaceae
(peels of fruits)
ndnd11.2 ± 0.1 µM a,mGAL
3.2 ± 0.2 µM a,m
MCE
5,7-Dihydroxy-8-(3-methylbutanoyl)-
6-[(E)-3,7-dimethylocta-2,6-dienyl]-4-phenyl-
2H-chromen-2-one
Mesua elegans Kosterm.
Clusiaceae
(bark)
3.06 ± 0.04 µM a,eTAC
0.074 ± 0.012 µM a,e
ndndCE[29,48]
Mesuagenin AMesua elegans Kosterm.
Clusiaceae
(bark)
1.06 ± 0.04 µM a,eTAC
0.074 ± 0.012 µM a,e
ndndCE
Mesuagenin BMesua elegans Kosterm.
Clusiaceae
(bark)
0.70 ± 0.10 µM a,eTAC
0.074 ± 0.012 µM a,e
ndndCE
Mesuagenin DMesua elegans Kosterm.
Clusiaceae
(bark)
8.73 ± 0.25 µM a,eTAC
0.074 ± 0.012 µM a,e
ndndCE
Lucidafuranocoumarin APeucedanum alsaticum L.
Apiaceae
(fruits)
naGAL
100 µg mL−1—92.14 ± 2.49% b,k
1.82 ± 0.22 µg mL−1 a,k
100 µg mL−1—40.66 ± 1.25% b,nGAL
100 µg mL−1—81.93 ± 2.52% b,n
22.16 ± 0.91 µg mL−1 a,n
MCE[102]
BergamottinPeucedanum alsaticum L.
Apiaceae
(fruits)
100 µg mL−1—4.00 ± 0.82% bGAL
100 µg mL−1—92.14 ± 2.49% b,k
1.82 ± 0.22 µg mL−1 a,k
100 µg mL−1—17.65 ± 1.50% bGAL
100 µg mL−1—81.93 ± 2.52% b,n
22.16 ± 0.91 µg mL−1 a,n
MCE
CHROMONES
Sargachromanol GSargassum siliquastrum
Sargassaceae
(strains)
1.81 ± 0.020 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
10.79 ± 0.65 µM a,mTAC
0.014 ± 0.0043 µM a,m
MCE[48,59,60]
Sargachromanol ISargassum siliquastrum
Sargassaceae
(strains)
0.79 ± 0.07 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
13.69 ± 5.07 µM a,mTAC
0.014 ± 0.0043 µM a,m
MCE
DIARYLHEPTANOIDS
(−)-Alpininoid BAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—87.6 ± 0.1% b,e
2.6 ± 4.2 µM a,e
TAC
111.8 ± 4.6 µM a,e
100 µM—64.7 ± 1.4% b,m
35.2 ± 0.7 µM a,m
TAC
8.9 ± 2.4 µM a,m
MCE[31,66]
(4E)−1,7-Diphenyl-4-hepten-3-oneAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—98.0 ± 0.9% b,e
23.9 ± 2.6 µM a,e
TAC
111.8 ± 4.6 µM a,e
100 µM—62.3 ± 3.5% b,m
70.7 ± 2.5 µM a,m
TAC
8.9 ± 2.4 µM a,m
MCE
DihydroyashsbushiketolAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—36.2 ± 1.9% b,eTAC
111.8 ± 4.6 µM a,e
100 µM—15.7 ± 2.1% b,mTAC
8.9 ± 2.4 µM a,m
MCE
(4E)-7-(4-Hydroxyphenyl)-1-phenyl-4-hepten-3-oneAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM –57.9 ± 3.2% b,e
87.3 ± 3.4 µM a,e
TAC
111.8 ± 4.6 µM a,e
100 µM—41.1 ± 0.1% b,mTAC
8.9 ± 2.4 µM a,m
MCE
(4E)-7-(4-Hydroxy-3-methoxyphenyl)-1-phenyl-hept-4-en-3-oneAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—76.6 ± 0.3% b,e
39.1 ± 2.3 µM a,e
TAC
111.8 ± 4.6 µM a,e
100 µM—43.7 ± 1.4% b,mTAC
8.9 ± 2.4 µM a,m
MCE
(5R)-7-(4-Hydroxy-3-methoxyphenyl)-5-methoxy-1-phenyl-3-heptanoneAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—35.3 ± 1.0% b,eTAC
111.8 ± 4.6 µM a,e
100 µM—21.5 ± 0.6% b,mTAC
8.9 ± 2.4 µM a,m
MCE
KaempferideAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—67.2 ± 1.8% b,e
31.9 ± 2.0 µM a,e
TAC
111.8 ± 4.6 µM a,e
100 µM –47.6 ± 1.6% b,mTAC
8.9 ± 2.4 µM a,m
MCE
GalanginAlpinia officinarum Hance
Zingiberaceae
(rhizomes)
100 µM—65.4 ± 4.5% b,e
70.1 ± 1.5 µM a,e
TAC
111.8 ± 4.6 µM a,e
100 µM—63.6 ± 3.1% b,m
61.4 ± 1.4 µM a,m
TAC
8.9 ± 2.4 µM a,m
MCE
DITERPENES
DihydrotanshinoneSalvia miltiorhiza Bunge
Lamiaceae
(roots)
1 μM a,dPHY
0.25 µM a,d
ndndMCE[38,103]
CryptotanshinoneSalvia miltiorhiza Bunge
Lamiaceae
(roots)
7 μM a,dPHY
0.25 µM a,d
ndndMCE
Tanshinone ISalvia miltiorhiza Bunge
Lamiaceae
(roots)
>50 μM a,dPHY
0.25 µM a,d
ndndMCE
Tanshionone IIASalvia miltiorhiza Bunge
Lamiaceae
(roots)
>140 μM a,dPHY
0.25 µM a,d
ndndMCE
Scapaundulin CScapania undulate L.
Scapaniaceae
>250 ng c,eGAL
>10 ng c,e
ndndBTLC
by Marston et al. (2002)
[104,105]
Scapaundulin
A
Scapania undulate L.
Scapaniaceae
>250 ng c,eGAL
>10 ng c,e
ndndBTLC
by Marston et al. (2002)
5α, 8α, 9α-Trihydroxy-13E-labden-12-oneScapania undulate L.
Scapaniaceae
>250 ng c,eGAL
>10 ng c,e
ndndBTLC
by Marston et al. (2002)
5α, 8α-
Dihydroxy-13E-labden-12-one
Scapania undulate L.
Scapaniaceae
>250 ng c,eGAL
>10 ng c,e
ndndBTLC
by Marston et al. (2002)
(13S)-15-Hydroxylabd-8
(17)-en-19-oic acid
Scapania undulate L.
Scapaniaceae
>500 ng c,eGAL
>10 ng c,e
ndndBTLC
by Marston et al. (2002)
FATTY ACID
(2E,4E,6R)-6-Hydroxydeca-
2,4-dienoic acid.
Lycopodiella cernua L.
Lycopodiaceae
(whole plants)
0.22 ± 0.03 µM a,kBER
0.10 ± 0.01 µM a,k
>30 µM a,nBER
1.09 ± 0.17 µM a,n
MCE[48,106]
FLAVONOIDS
3-Methoxy quercetinAgrimonia pilosa Ledeb.
Rosaceae
(leaves)
37.9 μM a,eDEH
37.8 μM a,e
ndndMCE[48,107]
QuercetinAgrimonia pilosa Ledeb.
Rosaceae
(leaves)
19.8 μM a,eDEH
37.8 μM a,e
ndndMCE
QuercitrinAgrimonia pilosa Ledeb.
Rosaceae
(leaves)
66.9 μM a,eDEH
37.8 μM a,e
ndndMCE
TilirosideAgrimonia pilosa Ledeb.
Rosaceae
(leaves)
23.5 μM a,eDEH
37.8 μM a,e
ndndMCE
LinarinBuddleja davidii Franch.
Buddlejaceae
(leaves)
>10 ng c,eHUP
>1 ng c,e
ndndBTLC
by Marston et al. (2002)
[101,104]
Garcineflavonol AGarcinia atroviridis Griff. ex T. Anderson
Clusiaceae
(stem bark)
100 μg mL−1—68.45 ± 0.97% b,e
14.04 ± 0.77 μg mL−1 a,e
PHY
0.05 ± 0.01 μg mL−1 a,e
14.50 ± 0.47 μg mL−1 a,mPHY
0.14 ± 0.015 μg mL−1 a,m
MCE[48,108,109]
QuercetinGinkgo biloba L.
Ginkgoaceae
(leaves)
95.8 μg mL−1 a,hCHL
12.4 μg mL−1 a,h
ndndMCE[48,110,111]
Quercetin-
3-O-𝛼-L-rhamnopyranosyl-
(1 → 6)-𝛽-D-glucopyranoside
Ginkgo biloba L.
Ginkgoaceae
(leaves)
73.1 μg mL−1 a,hCHL
12.4 μg mL−1 a,h
ndndMCE
Quercetin-3-O-
𝛽-D-glucopyranoside
Ginkgo biloba L.
Ginkgoaceae
(leaves)
57.8 μg mL−1 a,hCHL
12.4 μg mL−1 a,h
ndndMCE
Quercetin-3-O-𝛼-L-rhamnopyranosideGinkgo biloba L.
Ginkgoaceae
(leaves)
110.9 μg mL−1 a,hCHL
12.4 μg mL−1 a,h
ndndMCE
Quercetin-3-O-𝛼-L-rhamnopyranosyl-
(1 → 4)-O-𝛼-L-rhamnopyranosyl-
(1 → 2)-𝛽-D-glucopyranoside
Ginkgo biloba L.
Ginkgoaceae
(leaves)
112.6 μg mL−1 a,hCHL
12.4 μg mL−1 a,h
ndndMCE
TaxifolinGinkgo biloba L.
Ginkgoaceae
(leaves)
133.1 μg mL−1 a,hCHL
12.4 μg mL−1 a,h
ndndMCE
Quercetin-3-O-neohesperidoside Lysimachia clethroides Duby
Primulaceae
(whole plant)
6.98 ± 0.47 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
>40 µM a,mTAC
0.014 ± 0.0043 µM a,m
MCE[48,59,60]
DiplaconePaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
7.2 ± 0.6 µM a,fPHY
0.15 ± 0.03 µM a,f
1.4 ± 0.3 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF[34,48,112]
3′-O-MethyldiplacolPaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
48.5 ± 2.1 µM a,fPHY
0.15 ± 0.03 µM a,f
11.2 ± 2.1 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
3′-O-MethyldiplaconePaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
109.2 ±8.4 µM a,fPHY
0.15 ± 0.03 µM a,f
24.5 ± 1.2 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
4′-O-MethyldiplaconePaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
92.4 ± 4.1 µM a,fPHY
0.15 ± 0.03 µM a,f
25.6 ± 1.6 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
4′-O-MethyldiplacolPaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
31.9 ± 1.2 µM a,fPHY
0.15 ± 0.03 µM a,f
12.7 ± 1.3 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
6-Geranyl-3,3′,5,5′,7-pentahydroxy-
4′-methoxyflavane
Paulownia
tomentosa Steud.
Paulowniaceae
(fruits)
15.6 ± 0.8 µM a,f
PHY
0.15 ± 0.03 µM a,f
3.8 ± 0.8 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
6-Geranyl-3′,5,5′,7-tetrahydroxy-
4′-methoxyflavanone
Paulownia
tomentosa Steud.
Paulowniaceae
(fruits)
22.9 ± 1.6 µM a,fPHY
0.15 ± 0.03 µM a,f
6.4 ± 0.9 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
6-Geranyl-4′,5,7-trihydroxy-3′,5′-dimethoxyflavanonePaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
316.3 ± 12.5 µM a,fPHY
0.15 ± 0.03 µM a,f
80.00 ± 2.6 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
MimulonePaulownia
tomentosa Steud.
Paulowniaceae
(fruits)
91.5 ± 5.3 µM a,fPHY
0.15 ± 0.03 µM a,f
20.6 ± 1.1 µM a,mPHY
3.7 ± 0.6 µM a,m
MCEF
DihydrowogoninPrunus padus var. seoulensis Nakai
Rosaceae
(leaves)
21.53 ± 0.32 µM a,eTAC
0.22 ± 0.001 µM a,e
ndndMCE[48,59]
Dihydrowogonin 7-O-glucosidePrunus padus var. seoulensis Nakai
Rosaceae
(leaves)
15.49 ± 0.11 µM a,eTAC
0.22 ± 0.001 µM a,e
ndndMCE
GenkwaninPrunus padus var. seoulensis Nakai
Rosaceae
(leaves)
17.03 ± 0.77 µM a,eTAC
0.22 ± 0.001 µM a,e
ndndMCE
RhamnocitrinPrunus padus var. seoulensis Nakai
Rosaceae
(leaves)
18.26 ± 0.075 µM a,eTAC
0.22 ± 0.001 µM a,e
ndndMCE
3,5,7-Trihydroxy-8-methoxyflavanonePrunus padus var. seoulensis Nakai
Rosaceae
(leaves)
17.92 ± 0.63 µM a,eTAC
0.22 ± 0.001 µM a,e
ndndMCE
AmentoflavoneSelaginella doederleinii Hieron
Selaginellaceae
(whole plant)
0.73 ± 0.009 µM a,eTAC
1.26 ± 0.017 µM a,e
ndndMCE[48,113]
BilobetinSelaginella doederleinii Hieron
Selaginellaceae
(whole plant)
5.76 ± 0.021 µM a,eTAC
1.26 ± 0.017 µM a,e
ndndMCE
IsoginkgetinSelaginella doederleinii Hieron
Selaginellaceae
(whole plant)
4.11 ± 0.019 µM a,eTAC
1.26 ± 0.017 µM a,e
ndndMCE
RobustaflavoneSelaginella doederleinii Hieron
Selaginellaceae
(whole plant)
6.16 ± 0.032 µM a,eTAC
1.26 ± 0.017 µM a,e
ndndMCE
KaempferolSpiranthes sinensis Ames
Orchidaceae
(whole plant)
12.64 ± 0.31 a,kGAL
0.19 ± 0.02 µg/mL a,k
ndndMCE[48,114]
QuercetinSpiranthes sinensis Ames
Orchidaceae
(whole plant)
8.63 ± 0.37 a,kGAL
0.19 ± 0.02 µg/mL a,k
ndndMCE
LANOSTANE TRITERPENES
Methyl lucidenate E2Ganoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
17.14 ± 2.88 µM a,kBERCl
0.04 ± 0.01 µM a,k
>200 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE[48,115]
n-Butyl lucidenate AGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
12.26 ± 0.68 µM a,kBERCl
0.04 ± 0.01 µM a,k
>200 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
Ganoderic acid EGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
18.35 ± 2.95 µM a,kBERCl
0.04 ± 0.01 µM a,k
>200 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
N-Butyl ganoderate HGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
9.40 ± 0.88 µM a,kBERCl
0.04 ± 0.01 µM a,k
>200 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
LucidadiolGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
31.03 ± 1.69 µM a,kBERCl
0.04 ± 0.01 µM a,k
156.27 ± 6.12 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
Lucidenic acid NGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
25.91 ± 0.89 µM a,kBERCl
0.04 ± 0.01 µM a,k
188.36 ± 3.05 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
Lucidumol BGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
16.27 ± 0.51 µM a,kBERCl
0.04 ± 0.01 µM a,k
>200 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
n-Butyl lucidenate NGanoderma lucidum Karst.
Ganodermataceae
(fruiting bodies)
11.58 ± 0.36 µM a,kBERCl
0.04 ± 0.01 µM a,k
>200 µM a,nBERCl
18.97 ± 0.41 µM a,n
MCE
LIGNANS
MacelignanMyristica fragrans Houtt.
Myristicaceae
(seeds)
4.16 ± 0.070 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
9.69 ± 0.98 µM a,mTAC
0.014 ± 0.0043 µM a,m
MCE[48,59,60]
(+)-(7R,8S)-Erythro-4,7,9′-trihydroxy-8-O-4′-neolignan-9-O-β-D-glucopyranosideCamelia sinensis var. sinensis
Theaceae
(leaves and buds)
0.75 ± 0.04 µM a,eHUP
0.29 ± 0.05 µM a,e
ndndMCE[48,116,117]
(7S,8S)-Threo-4,9,9′-trihydroxy-8-O-4′-neolignan-7-O-β-D-glucopyranosideCamelia sinensis var. sinensis
Theaceae
(leaves and buds)
0.19 ± 0.02 µM a,eHUP
0.29 ± 0.05 µM a,e
ndndMCE
STILBENOID
Isoarundinin IIBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—0.9 ± 0.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—39.3 ± 2.3% b,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE[37,48]
PHENANTHRENES
1-[(4-Hydroxyphenyl)methyl]-4-methoxy-2,7-phenanthrenediolBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—19.1 ± 3.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—96.6 ± 1.2% b,m
2.1 ± 0.3 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE[37,48]
1,8-bis(4-Hydroxybenzyl)-4-methoxyphenanthrene-2,7-diolBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—16.1 ± 5.0% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—95.4 ± 0.3% b,m
2.3 ± 0.4 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
2,7-Dihydroxy-1,3-bi(p-hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthreneBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—20.1 ± 3.5% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—53.1 ± 1.2% b,m
44.6 ± 4.1 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
1-(p-Hydroxybenzyl)-4, 7-dimethoxyphenanthrene-2,8-diolBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—20.4 ± 4.5% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—85.2 ± 2.9% b,m
6.4 ± 0.2 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
3-(4-Hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene-2,7-diolBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—9.6 ± 2.6% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—65.7 ± 0.7% b,m
34.0 ± 1.4 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
9-(4′-Hydroxy-3′-
methoxyphenyl)-10-(hydroxymethyl)-11-methoxy-5,6,9, 10-tetrahydrophenanthro [2,3-b] furan-3-ol
Bletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—3.3 ± 1.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—61.2 ± 1.3% b,m
35.8 ± 9.2 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Bleformin ABletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—18.5 ± 1.7% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—70.0 ± 1.0% b,m
5.2 ± 0.4 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Bleformin BBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—9.9 ± 4.7% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—75.7 ± 1.1% b,m
16.7 ± 2.4 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Blestrin DBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—6.8 ± 1.6% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—69.0 ± 2.5% b,m
8.1 ± 0.5 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Blestrin ABletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—8.4 ± 3.1% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—64.0 ± 2.6% b,m
17.9 ± 4.7 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Blestrin CBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—4.9 ± 3.2% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—64.3 ± 2.4% b,m
12.1 ± 3.4 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Bletilol DBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—5.7 ± 2.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—31.6 ± 2.8% b,mGAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Bletilol EBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—5.1 ± 4.0% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—8.0 ± 2.4% b,mGAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
FavanthrinBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—13.3 ± 2.9% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—56.7 ± 2.0% b,m
42.2 ± 5.1 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
PholidotolBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1 –5.2 ± 3.2% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—29.1 ± 1.3% b,mGAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
ShancidinBletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—15.2 ± 3.6% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—72.8 ± 3.4% b,m
16.7 ± 2.0 µM a,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Shanciol F Bletilla striata Reichb. f.
Orchidaceae
(tuber)
25 μg mL−1—5.5 ± 1.8% b,eGAL
25 μg mL−1—94.8 ± 0.9% b,e
25 μg mL−1—21.8 ± 3.1% b,m
GAL
25 μg mL−1—64.2 ± 0.6% b,m
46.3 ± 5.8 µM a,m
TAC
0.0101 ± 0.0005 µM a,m
MCE
Cremaphenanthrene FCremastra appendiculata Makino
Orchidaceae
(tubers)
>200 µM a,eGAL
0.39 ± 0.04 µM a,e
14.62 ± 2.15 µM a,mGAL
1.12 ± 0.67 µM a,m
MCE[44,48]
Cremaphenanthrene GCremastra appendiculata Makino
Orchidaceae
(tubers)
>200 µM a,eGAL
0.39 ± 0.04 µM a,e
79.56 ± 0.78 µM a,mGAL
1.12 ± 0.67 µM a,m
MCE
PHENYLPROPANOIDS
Lapathoside AFallopia dentatoalata Holub
Polygonaceae
(aerial part)
30.6 ± 4.7 µM a,eTAC
0.1267 ± 0.0011 µM a,e
2.7 ± 1.7 µM a,mTAC
0.0055 ± 0.0017 µM a,m
MCE[48,118,119]
Lapathoside BFallopia dentatoalata Holub
Polygonaceae
(aerial part)
>100 µM a,eTAC
0.1267 ± 0.0011 µM a,e
10.9 ± 4.9 µM a,mTAC
0.0055 ± 0.0017 µM a,m
MCE
Smilaside G Fallopia dentatoalata Holub
Polygonaceae
(aerial part)
>100 µM a,eTAC
0.1267 ± 0.0011 µM a,e
17.1 ± 3.4 µM a,mTAC
0.0055 ± 0.0017 µM a,m
MCE
Smilaside JFallopia dentatoalata Holub
Polygonaceae
(aerial part)
56.0 ± 2.4 µM a,eTAC
0.1267 ± 0.0011 µM a,e
10.1 ± 4.6 µM a,mTAC
0.0055 ± 0.0017 µM a,m
MCE
Vanicoside BFallopia dentatoalata Holub
Polygonaceae
(aerial part)
32.3 ± 4.7µM a,eTAC
0.1267 ± 0.0011 µM a,e
7.5 ± 4.1 µM a,mTAC
0.0055 ± 0.0017 µM a,m
MCE
PHLOROTANNINS
974-B Eisenia bicyclis
(Kjellman) Stechell
Laminariaceae
(leafy thalli)
1.95 ± 0.01 μM a,eBER
0.22 ± 0.03 µM a,e
3.26 ± 0.08 µM a,mBER
11.74 ± 0.85 µM a,m
CE[48,120]
PHTHALATES
bis (7-Acetoxy-2-ethyl-
5-methylheptyl) phthalate
Lonicera quinquelocularis Hard.
Caprifoliaceae
(whole plant)
1.65 ± 0.03 µM a,kGAL
1.79 ± 0.061 µM a,k
5.98 ± 0.079 µM a,mGAL
7.98 ± 0.01 µM a,m
MCE [48,51,121]
Neopentyl-4-hydroxy-3,5-bis (3-methyl-2-butenyl) benzoateLonicera quinquelocularis Hard.
Caprifoliaceae
(whole plant)
3.43 ± 0.02 µM a,kGAL
1.79 ± 0.061 µM a,k
9.84 ± 0.037 µM a,mGAL
7.98 ± 0.01 µM a,m
MCE
PHENOLIC ACIDS
4-Hydroxybenzoic acid methyl esterSpiranthes sinensis Ames
Orchidaceae
(whole plant)
42.89 ± 1.21 a,kGAL
0.19 ± 0.02 µg/mL a,k
ndndMCE[48,114]
Ethyl ferulateSpiranthes sinensis Ames
Orchidaceae
(whole plant)
19.97 ± 1.05 a,kGAL
0.19 ± 0.02 µg/mL a,k
ndndMCE
3-(4-Tolyloxy)-propanoic acidSpiranthes sinensis Ames
Orchidaceae
(whole plant)
15.31 ± 0.64 a,kGAL
0.19 ± 0.02 µg/mL a,k
ndndMCE
POLYKETIDES
Aspilactonol GPhaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE[48,122,123]
Aspilactonol HPhaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
Aspilactonol IPhaeospaeria sp. LF5
(strain from Huperzia serrata)
6.26 ± 0.15 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
de-O-Methyldiaporthin Phaeospaeria sp. LF5
(strain from Huperzia serrata)
21.18 ± 1.53 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
6,8-Dihydroxy-3-(10R, 20R-dihydroxypropyl)-isocoumarinPhaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
E2-Anhydromevalonic acidPhaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
2-(1-Hydroxyethyl)-6-
methylisonicotinic acid
Phaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
6-Hydroxy-8-methoxy-3-
methylisocoumarin
Phaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
3-(Hydroxymethyl)-5-methylfuran-2(5H)-onePhaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
4-Methyl-5,6-dihydropyren-2-one Phaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
(R)-6-Hydroxymellein Phaeospaeria sp. LF5
(strain from Huperzia serrata)
>100 µM a,kRIV
1.82 ± 0.13 µM a,k
HUP
0.045 ± 0.01 µM a,k
ndndMCE
Asterric acidTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
66.7 ± 1.7 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e
>100 µM a,mnsMCE[48,91,92]
Ethyl asterrateTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
20.1 ± 0.9 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e
>100 µM a,mnsMCE
Methyl asterrateTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
23.3 ± 1.2 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e
>100 µM a,mnsMCE
SulochrinTalaromyces aurantiacus FL 15
(strain from leave Huperzia serrata)
>100 µM a,eRIV
1.82 ± 0.13 µM a,e
HUP
0.045 ± 0.01 µM a,e
>100 µM a,mnsMCE
POLYPHENOLS
Broussonin AAnemarrhena asphodeloides
Bunge
Asparagaceae
(roots)
15.88 ± 1.02 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
7.50 ± 0.07 µM a,mTAC
0.014 ± 0.0043 µM a,m
MCE[48,59,60]
MangiferinAnemarrhena asphodeloides Bunge Asparagaceae
(whole plant)
62.8 µM a,gTAC
nd a,g
ndndMCE[48,124]
Caffeoylated catechinCamellia sinensis var. assamica
Theaceae
(leaves)
2.49 ± 0.43 µM a,eHUP
0.088 ± 0.004 µM a,e
nddMCE[48,116]
Epigallocatechin 3-O-p-coumaroateCamellia sinensis var. assamica
Theaceae
(leaves)
11.41 ± 2.00 µM a,eHUP
0.088 ± 0.004 µM a,e
ndndMCE
Epigallocatechin-3-O-ferulateCamellia sinensis var. assamica
Theaceae
(leaves)
62.26 ± 10.18 µM a,eHUP
0.088 ± 0.004 µM a,e
ndndMCE
Creoside IVCodonopsis pilosula Nannf
Campanulaceae
(roots)
7.30 ± 0.49 µM a,eBER
1.01 ± 0.01 µM a,e
TAC
0.22 ± 0.004 µM a,e
>40 a,mTAC
0.014 ± 0.0043 µM a,m
MCE[48,59,60]
Heyneanol AVitis amurensis Rupr.
Vitaceae
(roots)
1.66 ± 0.09 µM a,fGAL
0.93 ± 0.07 µM a,f
1.75 ± 0.09 µM a,lGAL
9.24 ± 1.32 µM a,l
MCE[48,125]
Vitisin AVitis amurensis Rupr.
Vitaceae
(roots)
1.04 ± 0.05 µM a,fGAL
0.93 ± 0.07 µM a,f
4.41 ± 0.39 µM a,lGAL
9.24 ± 1.32 µM a,l
MCE
SESQUITERPENE LACTONES
BritanninInula aucheriana DC.
Asteraceae
(aerial parts)
300 μg mL−1—25.2% b,kDONndndMCE[48,126]
GaillardinInula oculus-christi L.
Asteraceae
(aerial parts)
300 μg mL−1—67% b,kDONndndMCE
Pulchellin CInula oculus-christi L.
Asteraceae
(aerial parts)
300 μg mL−1—10.9% b,kDONndndMCE
AmberinAmberboa ramosa Jafri.
Asteraceae
(whole plant)
17.5 ± 0.01 μM a,eGAL
0.5 ± 0.01 μM a,e
PHY
0.04 ± 0.0001 μM a,e
2.7 ± 0.02 μM a,mGAL
8.2 ± 0.02 μM a,m
PHY
0.82 ± 0.001 μM a,m
MCE[48,127]
Amberbin AAmberboa ramosa Jafri.
Asteraceae
(whole plant)
8.6 ± 0.15 μM a,eGAL
0.5 ± 0.01 μM a,e
PHY
0.04 ± 0.0001 μM a,e
4.8 ± 0.15 μM a,mGAL
8.2 ± 0.02 μM a,m
PHY
0.82 ± 0.001 μM a,m
MCE
Amberbin BAmberboa ramosa Jafri.
Asteraceae
(whole plant))
0.91 ± 0.015 μM a,eGAL
0.5 ± 0.01 μM a,e
PHY
0.04 ± 0.0001 μM a,e
2.5 ± 0.15 μM a,mGAL
8.2 ± 0.02 μM a,m
PHY
0.82 ± 0.001 μM a,m
MCE
Amberbin CAmberboa ramosa Jafri.
Asteraceae
(whole plant)
1.1 ± 0.08 μM a,eGAL
0.5 ± 0.01 μM a,e
PHY
0.04 ± 0.0001 μM a,e
17.9 ± 0.05 μM a,mGAL
8.2 ± 0.02 μM a,m
PHY
0.82 ± 0.001 μM a,m
MCE
ZerumboneZingiber zerumbet L.
Zingiberaceae
(whole plant)
1 mg mL−1 c,kTAC
10 mM c,k
ndndBTLC
by Rhee et al. (2001)
[16,128]
Silphiperfolene acetateLeontopodium alpinum Cass.
Asteraceae
(sub-aerial parts)
200 μM—40.64 ± 7.09% b,kGAL
3.2 µM a,k
GAL
100 μM—89.30 ± 2.29% b,k
ndndMCE[93,95,129]
STEROIDS
LeucisterolLeucas urticifolia Vahl.
Lamiaceae
(whole plant)
83.6 ± 0.59 µM a,kPHY
0.04 µM a,k
3.2 ± 0.85 µM a,nPHY
0.93 ± 0.3 µM a,n
CE[48,130]
STEROLS
Haloxylon AHaloxylon recurvum Bunge ex Boiss
Chenopodiaceae
(whole plant)
8.3 ± 0.02 µM a,eGAL
0.5 ± 0.001 µM a,e
4.7 ± 0.01 µM a,mGAL
8.5 ± 0.00 µM a,m
MCE[48,131]
Haloxylon BHaloxylon recurvum Bunge ex Boiss
Chenopodiaceae
(whole plant)
0.89 ± 0.002 µM a,eGAL
0.5 ± 0.001 µM a,e
2.3 ± 0.001 µM a,mGAL
8.5 ± 0.00 µM a,m
MCE
TRIFLAVANONES
Garcineflavanone AGarcinia atroviridis Griff. ex T. Anders.
Clusiaceae
(stem bark)
100 μg mL−1—80.15 ± 6.65% b,e
28.52 ± 5.23 μg mL−1 a,e
PHY
0.05 ± 0.01 μg mL−1 a,e
nsPHY
0.14 ± 0.015 μg mL−1 a,m
MCE[48,108,109]
TRITERPENOIDS
Arbora-
1,9(11)-dien-3-one
Buxus hyrcana Pojark.
Buxaceae
(leaves)
47.9 ± 1.2 µM a,kGAL
0.53 ± 0.5 µM a,k
HUP
1.7 ± 0.3 µM a,k
220.1 ± 1.0 µM a,nGAL
8.7 ± 1.0 µM a,n
HUP
>1000 ± 3.0 µM a,n
MCE[48,56,57,58]
Asiatic acidCentella asiatica Urb
Apiaceae
(whole plant)
15.05 ± 0.05 µM a,ePHY
0.05 ± 0.12 µM a,e
ndndMCE[48,132,133]
AsiaticosideCentella asiatica Urb
Apiaceae
(whole plant)
59.13 ± 0.18 µM a,ePHY
0.05 ± 0.12 µM a,e
ndndMCE
Madecassic acidCentella asiatica Urb
Apiaceae
(whole plant)
17.83 ± 0.06 µM a,ePHY
0.05 ± 0.12 µM a,e
ndndMCE
MadecassosideCentella asiatica Urb
Apiaceae
(whole plant)
37.14 ± 0.04 µM a,ePHY
0.05 ± 0.12 µM a,e
ndndMCE
BetulinGarcinia hombroniana Pierre
Clusiaceae
(bark)
28.5 ± 0.78 µM a,ePHY
0.04 ± 0.004 µM a,e
ndPHY
0.09 ± 0.003 µM a,m
MCE[48,81]
Betulinic acidGarcinia hombroniana Pierre
Clusiaceae
(bark)
24.2 ± 0.99 µM a,ePHY
0.04 ± 0.004 µM a,e
19.1 ± 1.33 µM a,mPHY
0.09 ± 0.003 µM a,m
MCE
2β-Hydroxy-3α-O-caffeoyltaraxar-14-en-28-
oic acid
Garcinia hombroniana Pierre
Clusiaceae
(bark)
13.5 ± 0.95 µM a,ePHY
0.04 ± 0.004 µM a,e
10.6 ± 0.54 µM a,mPHY
0.09 ± 0.003 µM a,m
MCE
TaraxerolGarcinia hombroniana Pierre
Clusiaceae
(bark)
ndPHY
0.04 ± 0.004 µM a,e
17.8 ± 1.73 µM a,mPHY
0.09 ± 0.003 µM a,m
MCE
21β-Hydroxyserrat-
14-en-3,16-dione
Lycopodiella cernua L.
Lycopodiaceae)
(whole plants)
10.67 ± 0.66 µM a,kBER
0.10 ± 0.01 µM a,k
>30 µM a,nBER
1.09 ± 0.17 µM a,n
MCE[48,106]
3β,21α-Diacetoxyserratan-
14β-ol
Lycopodiella cernua L.
Lycopodiaceae
(whole plants)
0.91 ± 0.01 µM a,kBER
0.10 ± 0.01 µM a,k
>30 µM a,nBER
1.09 ± 0.17 µM a,n
MCE
3β,21β,29-Trihydroxyserrat-
14-en-3β-yl
p-dihydrocoumarate
Lycopodiella cernua L.
Lycopodiaceae
(whole plants)
1.69 ± 0.10 µM a,kBER
0.10 ± 0.01 µM a,k
0.42 ± 0.01 µM a,nBER
1.09 ± 0.17 µM a,n
MCE
SESQUITERPENES
1α-Acetoxy-6β,9β-difuroyloxy-4β-hydroxydihydro-β-agarofuranMaytenus disticha Urb.
Celastraceae
(seeds)
738.0 ± 0.007 µM a,eGAL
10.0 ± 0.015 µM a,e
CAR
45.0 ± 0.031 µM a,e
ns a,mns a,mMCE[48,134]
6β-Acetoxy-9β-benzyloxy-1α,8α-dihydroxydihydro-β-agarofuranMaytenus disticha Urb.
Celastraceae
(seeds)
500.0 ± 0.03 µM a,eGAL
10.0 ± 0.015 µM a,e
CAR
45.0 ± 0.031 µM a,e
ns a,mns a,mMCE
6β,8α-Diacetoxy-9β-furoyloxy-1α-hydroxydihydro-β-agarofuran Maytenus disticha Urb.
Celastraceae
(seeds)
740.0 ± 0.045 µM a,eGAL
10.0 ± 0.015 µM a,e
CAR
45.0 ± 0.031 µM a,e
ns a,mns a,mMCE
1α,6β,14-Triacetoxy-9β-benzyloxydihydro-β-agarofuranMaytenus magellanica Hook.f.
Celastraceae
(seeds)
695.0 ± 0.001 µM a,eGAL
10.0 ± 0.015 µM a,e
CAR
45.0 ± 0.031 µM a,e
ns a,mns a,mMCE
2α,3β,6β-Triacetoxy-1α,9β-dibenzyloxy-4β-hydroxydihydro-β-agarofuranMaytenus magellanica Hook.f.
Celastraceae
(seeds)
30.0 ± 0.06 µM a,eGAL
10.0 ± 0.015 µM a,e
CAR
45.0 ± 0.031 µM a,e
ns a,mns a,mMCE
XANTHONES
BellidinGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—17.5 ± 5.7% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
[42,48,101,135]
BellidifolinGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—21.9 ± 6.2% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
Corymbiferin 1-O-glucosideGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—1.5 ± 1.2% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
Corymbiferin 3-O-β-D-glucopyranosideGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—17.6 ± 1.8% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
nor-SwertianolinGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—4.4 ± 4.4% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
SwertianolinGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—9.8 ± 3.9% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
Swertiabisxanthone-IGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—20.9 ± 3.3% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
Swertiabisxanthone-I 8′-O-β-D-glucopyranosideGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—12.3 ± 2.9% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
Triptexanthoside CGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—43.7 ± 3.3% b,e
13.8 ± 1.6 µM a,e
GAL
10 μM—96.82 ± 0.04% b,e
GAL
0.35 ± 0.02 µM a,e
ndndMCE
BTLC
by Marston et al. (2002)
VeratrilosideGentianella amarella ssp. acuta
J.M.Gillett
Gentianaceae
(whole plants)
10 μM—28.2 ± 2.5% b,eGAL
10 μM—96.82 ± 0.04% b,e
ndndMCE
BTLC
by Marston et al. (2002)
XANTHONOIDS
Allanxanthone EGarcinia mangostana L.
Clusiaceas
(seedcases)
15.0 ± 1.2 µM a,f
67.4 ± 0.3 µM a,e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
11.0 ± 0.4 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF[48,112,136]
α-MangostinGarcinia mangostana L.
Clusiaceas
(seedcases)
8.0 ± 0.5 µM a,f
6.3 ± 0.6 µM a,e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
2.9 ± 0.7 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF
8-DeoxygartaninGarcinia mangostana L.
Clusiaceas
(seedcases)
6.2 ± 0.3 µM a,f
11.0 ± 0.6 µM e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
9.2 ± 0.5 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF
γ-MangostinGarcinia mangostana L.
Clusiaceas
(seedcases)
5.4 ± 0.3 µM a,f
2.5 ± 3.3 µM a,e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
0.7 ± 0.03 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF
GudraxanthoneGarcinia mangostana L.
Clusiaceas
(seedcases)
11.7 ± 0.7 µM a,f
18.9 ± 1.7 µM a,e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
9.0 ± 1.2 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF
9-Hydroxy-calabaxanthoneGarcinia mangostana L.
Clusiaceas
(seedcases)
>100 µM a,f
>100 µM a,e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
86.3 ± 2.4 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF
MangostanolGarcinia mangostana L.
Clusiaceas
(seedcases)
14.6 ± 0.7 µM a f
6.3 ± 5.4 µM a,e
PHY
0.043 ± 0.002 µM a,f
0.049 ± 0.003 µM a,e
6.0 ± 0.2 µM a,mPHY
0.073 ± 0.006 µM a,m
MCEF
MISCELLANOUS
3-Methylbuthyl hydrodisulfideButhus martensii Karsch
Buthidae
(whole body of scorpion)
40.93 ± 3.21 µM a,eGAL
1.17 ± 0.01 µM a,e
DON
0.049 ± 0.004 µM a,e
152.84 ± 7.22 µM a,mGAL
18.78 ± 1.81 µM a,m
DON
5.536± 0.018 µM a,m
MCE[48,54,55]
2-BenzothiazololSpiranthes sinensis Ames
Orchidaceae
(whole plant)
37.67 ± 0.52 a,kGAL
0.19 ± 0.02 µg/mL a,k
ndndMCE[48,114]
Abbreviations in Table 1: nd—not determined; ns—not shown; a—inhibitory concentration for which enzyme activity is equal to half-maximal (IC50)/(IC50) ± S.E.M.; b—percentage of inhibition against enzyme (xμg mL−1-y%, xμM—y%); c—minimal inhibitory quantity (MIC); d—IC50 against bovine acetylcholinesterase (bAChE); e—IC50 against Electrophorus electricus acetylcholinesterase (eeAChE); f—IC50 against human erythrocyte acetylcholinesterase (hAChE); g—IC50 against mice hippocampus acetylcholinesterase; h—against Nilaparvata lugens acetylcholinesterase; i—IC50 against rat cortical acetylcholinesterase; j—against Torpedo californica acetylcholinesterase; k—against acetylcholinesterase not specified in the publication; l—IC50 against human butyrylcholinesterase; m—IC50 against Equus caballus butyrylcholinesterase; n—against butyrylcholinesterase not specified in the publication. ALA—allanzanthane A; CAR—carvacrol; GAL—galanthamine; TAC—tacrine; HUP—huperzine A; BER—berberine; BERCl—berberine chloride; PHY—physostigmine (eserine); DEH—dehydroevodiamine; CHL—chlorpyrifos; DON—donepezil; NEO—neostigmine bromide; MCE—modified colorimetric Ellman’s method; CE—colorimetric Ellman’s method; BTLC—bioautography TLC; MCEF—modified colorimetric Ellman’s method and fluorescence measurement.

3. Activity

A comparison of the activity of individual isolated compounds is presented in Table 1.
Based on the information provided in Table 1, higher activity against AChE relative to galanthamine (1) is exhibited by the alkaloids aconorine, berberine (7), coptisine (9), 1,2-dihydrogalanthamine, epiberberine, jadwarine-A, jatrorrhizine, N-allyl-nor-galanthamine (4), N-(14-methylallyl)-nor-galanthamine (5), sanguinine (6), phthalates (e.g., bis (7-acetoxy-2-ethyl-5-methylheptyl) phthalate) and sterols (haloxylon B); relative to berberine (7), sargachromanol I (chromones) shows stronger inhibitory activity; relative to dehydroevodiamine, tiliroside and quercetin (flavonoids) have stronger inhibitory activity; compared to huperzine A, (7S,8S)-threo-4,9,9′-trihydroxy-8-O-4′-neolignan-7-O-β-D-glucopyranoside (lignans) has stronger inhibitory activity; compared to physostigmine (eserine), discorhabdin G (alkaloids) has stronger inhibitory activity; relative to neostigmine bromide, 7,8-didehydroorientalidine TFA salt and orientalidine (alkaloids) have stronger inhibitory activity; and compared to tacrine, 7-epi-javaniside, six diarylheptanoids from Alpinia officinarum and amentoflavone (flavonoids) show stronger inhibitory activity.
In the case of BuChE inhibitors, stronger BuChE inhibitory activity relative to galanthamine (1) is shown not only by the alkaloids aconorine, angustidine (2), angustine, angustoline, deoxyvobtusine, harmane, hohenackerine, jadwarine-A, nauclefine and pyrroloquinolone A, but also the bibenzyls bulbocol and gymconopin D; the coumarins bergapten, imperatorin (17), heraclenol-2′-O-angelate (18) and xanthotoxin; the phthalate bis (7-acetoxy-2-ethyl-5-methylheptyl) phthalate; the polyphenols vitisin A and heyneanol A; twelve phenanthrenes from Bletilla strata; the sesquiterpene lactones amberin, amberbin A and amberbin B; and the sterols haloxylon A and haloxylon B. In comparison to berberine (7), stronger inhibitory activity is exerted by sargachromanol I (chromones), 3β,21β,29-trihydroxyserrat-14-en-3β-yl p-dihydrocoumarate (triterpenoids) and compound 974-B (phlorotannins); relative to physostigmine, discorhabdin C and G (alkaloids) and diplacone (30) (flavonoids) show stronger inhibitory activity; relative to neostigmine bromide, alborine, isothebaine and N-methylisothebainium (alkaloids) have stronger inhibitory activity; and relative to tacrine, 7-epi-javaniside (alkaloids) has stronger inhibitory activity.
There are compounds that act more selectively and more potently on AChE versus (vs.) BuChE. The majority of them are alkaloids, including alborine, 9-O-demetil-2-α-hydroxyhomolycorine, 7,8-didehydromecambridine TFA salt, 7,8-didehydroorientalidine TFA salt, dihydroberberine (8), discorhabdin B, G and L, chlidanthine, hendersine B, hydrohydrastinine, 10-hydroxy-infractopicrin, 11-hydroxygalanthine, infractopicrin, mucroniferanines H, narcissidine, orientalidine, sanguinine (6), sargachromanol G and I, and vincosamide from Buxus hyrcana (except 31-demethylcyclobuxoviridine and papillozine C). Additionally, ethyl asterrate, methyl asterrate (anthranoids), (−) alpininoid B (23), (4E)-1,7-diphenyl-4-hepten-3-one (24) and other diarylheptanoids from Alpinia officinarum (diarylheptanoids), sargachromanol G and I (chromones), (2E,4E,6R)-6-hydroxydeca-2,4-dienoic acid (fatty acid), quercetin-3-O-neohesperidoside (flavonoids), methyl lucidenate E2, n-butyl lucidenate A and, n-butyl ganoderate H, ganoderic acid E, garcineflavanone A, lucidanol, lucidenic acid, lucidumol B (lanostane triterpenes), macelignan (lignans), creoside IV (polyphenols), amberbin C (sesquiterpene lactones), 3β,21α-diacetoxyserratan-14β-ol and 21β-hydroxyserrat-14-en-3,16-dione (triterpenoids) represent the same feature.
The following compounds are more selective and act more potently on BuChE vs. AChE: angustine, angustidine (2), angustoline, 31-demethylcyclobuxoviridine, harmane, isothebaine, lupanine, 2-methoxyatherosperminine, 4-methoxy-1-methyl-2-quinolone, narcipavline, nauclefine, pancratinine-C, papillozine C, pyrroloquinolone A, strictosamide (alkaloids), acetylvismione, bianthrone 1a, 2-geranylemodin, 3-geranyloxyemodin anthrone, 3-prenyloxyemodin, 3-prenyloxyemodin anthrone (anthranoids), bibenzyls from Bletilla striata (bibenzyls), bergapten, imperatorin (17), heraclenol-2′-O-angelate (18), xanthotoxin (coumarins), diplacone (30), 6-geranyl-3,3′,5,5′,7-pentahydroxy-4′methoxyflavane, 6-geranyl-3′,5,5′,7-tetrahydroxy-4′methoxyflavanone, 3′-O-methyldiplacol, 3′-O-methyldiplacone, 4′-O-methyldiplacol, 4′-O-methyldiplacone (33), mimulone (flavonoids), heyneanol A, vitisin A (polyphenols), cremaphenanthrene F and phenanthrenes from Bletilla striata (37,38) (phenanthrenes), amberin, amberbin A, (sesquiterpene lactones), leucisterol (steroids) and 3β,21β,29-trihydroxyserrat-14-en-3β-yl p-dihydrocoumarate (triterpenoids). On the basis of the IC50 value (µM) for galanthamine (1) obtained in the study and presented in Table 1, the median for AChE was determined, and it was IC50 = 0.94 µM, and for BuChE, it was 8.70 µM. It was assumed that galanthamine (1) exhibits strong inhibition of AChE and BuChE, and the potency of other inhibitors was compared to the value of the determined median. Those with IC50 under 1.5 μM were considered strong, those under 20 µM were medium-strong, and those between 20 and 100 µM were weak for AChE. For BuChE, those with IC50 under 10 μM were considered strong, those between 10 and 50 μM were medium-strong, and those in the range of 50–150 μM were weak.
From the presented tabular comparison (Table 1) of the results of the conducted studies (values of IC50), it follows that the compounds belonging to the alkaloid group exhibit the strongest activity against AChE and therefore are discussed in more detail. Fourteen of them have strong inhibitory activity with an IC50 value < 1.5 µM, and forty-two have medium-strong activity below 20 µM (Table 1).
The best AChE inhibition result in the entire table (Table 1) was obtained for sanguinine (IC50 = 0.007 µM). This was confirmed in another independent study in which the compound was derived from a different plant material (IC50 = 0.10 µM). Strong activity against AChE was also detected for five other Amaryllidaceae alkaloids (IC50 = 0.16 µM, 0.18 µM, 0.19 µM, 0.67 µM, 0.99 µM).
The different values of the inhibition coefficient obtained for sanguinine (6) are probably due to the use of various origins of AChE in the two studies. Similarly, for the same Amaryllidaceae alkaloids, e.g., lycoramine, inconsistent results were observed, with potent activity against Electric eel AChE and inactivity or weak activity using human AChE (isolated from Narcissus jonquilla ‘Pipit’ and Narcissus poeticus ‘Pink Parasol’).
Stronger and more potent AChE inhibitory activity than galanthamine (1) was obtained for five other isoquinoline alkaloids of the protoberberine type (IC50 = 0.52 µM, 0.53 µM, 0.51 µM, 0.74 µM, 0.80 µM) isolated from Mahonia bealei and Mahonia fortunei, as well as medium-strong activity for three Mahonia alkaloids (IC50 = 5.07–13.3 µM).
Values of the IC50 inhibition coefficient of AChE below 1.5 μM were demonstrated by alkaloids derived from the sponge Latrunculia biformis (discorhabdin G) and an alkaloid from Lycopodium, huperzine C, with a slightly weaker result than the known activity of huperzine A.
Fourteen alkaloids from Ranunculaceae exhibit strong or medium-strong AChE inhibition values (IC50 = 2.51–12.1 µM), including an isoquinoline alkaloid, dihydroberberine (8), with IC50 = 1.18 µM (from Coptis chinensis), and diterpenoid alkaloids, including aconorine (from Aconitum laeve) and jadwarine-A (from Delphinium denudatum), with a potential stronger than the reference galanthamine (1) (Table 1).
Similar moieties that are crucial for the binding of the inhibitor to the enzyme are also present in other strong and medium-strong inhibitors from other groups of compounds present in Table 1.
Lipophilic substituents will have a stronger affinity for the hydrophobic AChE ester part; hence, they show stronger binding to the enzyme and greater inhibition, which is described in more detail in the chemistry–structure–activity section [1,43].
A BuChE inhibition study showed inhibitory activity for thirty-one alkaloids with inhibition coefficients ranging from 10 to 50 µM and strong activity for alkaloids with inhibition coefficients below 10 µM. Alkaloids isolated from Nauclea officinalis (IC50 = 1.03 µM, 4.98 µM, 7.70 µM), including angustidine (2), have the lowest inhibition coefficients of all the alkaloids listed in Table 1.
The group of alkaloids is distinguished by a strong inhibitory effect on BuChE: alkaloids isolated from Papaver somniferum (IC50 = 2.80 µM, 7.1 µM), including one about thirty times more potent than neostigmine; two alkaloids stronger than galanthamine (1) from Aconitum laeve (IC50 = 8.72 µM, 9.94 µM) and deoxyvobtusine (IC50 = 6.20 µM) from Voacanga globosa; two alkaloids more potent than physostigmine, i.e., discorhabdin G (IC50 = 7.00 µM) from Latrunculia bocagei and 2-methoxyatherosperminine from Cryptocarya griffithiana (IC50 = 3.95 µM); and two alkaloids more potent than tacrine from Uncaria rynchophylla (Table 1).
From the coumarin group, coumarins isolated from Mesua elegans (IC50 = 0.70 µM, 1.06 µM, 3.06 µM) have the strongest ability to inhibit AChE. Four of them exhibit medium activity with an IC50 value <10 µM. Their activity against BuChE has not been studied. However, other presented coumarins displayed in the results seem to show BuChE inhibition (bergapten, imperatorin (17) and xanthotoxin (Table 1)). The IC50 values of coumarins isolated from Archangelicae officinalis and Citrus hystrix (Table 1) prove their activity against BuChE (IC50 from 7.5 to 23 µM) as well.
From all of the presented flavonoids, linarin from Buddleja davidii requires the minimal inhibitory quantity (10 ng) to inhibit AChE. Diplacone (30) and quercetin-3-O-neohesperidoside demonstrate the strongest activity against AChE, as determined by their IC50 values (IC50 = 7.2 µM, 6.98 µM). Medium-strong inhibitor values are reported for quercetin and tiliroside from Agrimonia pilosa and five flavonoids from Prunus padus var. seoulensis (IC50 between 15.49 and 21.53 µM) (Table 1). Flavonoids isolated from Paulownia tomentosa show relatively medium or weak activity against AChE (values of IC50 between 7.2 µM and 109.2 µM) and significant activity against BuChE (the strongest compounds demonstrated IC50 =1.4 µM, 3.8 µM). Garcineflavonol A (IC50 = 14.50 µM) showed medium-strong activity against BuChE. Lanostane triterpenes from Ganoderma lucidum showed medium activity against AChE, ranging from 9.40 µM to 31.03 µM, and n-butyl ganoderate H reached a value of IC50 = 9.40 µM. However, most of the results against BuChE are IC50 > 200 µM, which may indicate the selective activity of these compounds on AChE. Conversely, cremaphenanthrene F (phenanthrenes) from Cremastra appendiculata shows more potent inhibition against BuChE vs. AChE. Two lignans from Camelia sinensis var. sinensis ‘Huangjinya’ revealed strong AChE inhibition, which was higher or slightly weaker than huperzine (Table 1). Strong activity against BuChE and medium-strong activity against AChE were achieved for another lignan: macelignan from Myristica fragrans. The phlorotannin compound 974-B reached satisfactory results for both cholinesterases (for AChE IC50 = 1.95 µM and for BuChE IC50 = 3.26 µM).
Similarly, phthalates from Lonicera quinquelocularis had IC50 = 1.65 µM and 3.43 µM for AChE and IC50 < 10 µM for BuChE. Among diterpenes, dihydrotanshinon I and cryptotanshinone (40) showed strong inhibition against AChE, and triptexanthoside C (45) (xanthones) showed significant inhibition. Xanthonoids from Garcinia mangostana had IC50 on AChE from 2.5 μM, with six compounds having IC50 < 20 μM, and IC50 on BuChE from 0.7 μM, with six compounds having IC50 < 12 μM. Anthranoids from Psorospermum glaberrimum demonstrated medium-strong activity toward BuChE (9.25–13.30 μM) and weak activity toward AChE. A fatty acid from Lycopodiella cernua has shown high inhibition of AChE (0.22 μM). Remarkable results are also shown by polyphenols from Camellia sinensis var. assamica (caffeoylated catechin) against AChE, as well as by polyphenols from Vitis amurensis (heyneanol A, vitsin A), which had strong activity against AChE and BuChE. Medium-strong inhibition of AChE by creoside IV from Codonopsis pilosula and strong inhibition against BuChE by broussonin A (Anemarrhena asphodeloides) were found. High inhibition values against AChE and BuChE were also observed for sesquiterpene lactones from Amberboa ramosa (amberin, amberbin A and amberbin B). Sterols (leucisterol, haloxylon A and haloxylon B) from Haloxylon recurvum have shown strong inhibition of both BuChE and AChE. A strong inhibition value against AChE and medium inhibition against BuChE were shown by chromones from Sargassum siliquastrum and one of the diarylheptanoids: (−)-alpininoid B (23) (Table 1). Terpenoids demonstrated strong (Lycopodiella cernua) or medium-strong (Lycopodiella cernua or Garcinia hombroniana) activity against AChE and BuChE. All results are presented in Table 1.

4. Analysis Methods

The studied compounds occur in materials of natural origin in the form of mixtures. To determine the change in enzyme activity due to a particular compound, it is necessary to purify samples or even fractionate them. Studies of inhibitory activity toward cholinesterases in scientific reports are performed according to different methods and procedures. Nevertheless, in most cases, analyses are based on Ellman’s assay [48]. A summary of analysis methods used in the selected studies of cholinesterase inhibition is presented in Table 1. The description of the most important one is presented below.
The method should be simple, quick to perform, sensitive and inexpensive [77,137]. The analysis methods are based on a colorimetric assay using chromatographic techniques, TLC and fluorimetric and spectrophotometric measurements.
These methods are based on measuring changes in parameters indicative of enzyme activity before and after the introduction of the inhibitor to the system. Even slight changes in temperature, incubation time, pH, the concentration of substrates and the enzyme and the presence of other interfering compounds (detergents and heavy metal ions) can affect the accuracy of the results.

4.1. The Colorimetric Method of Ellman (1961)

This procedure is based on the result of the color reaction between the formed pre-thiocholine and the DTNB color developer (5,5′-dithiobis-(2-nitrobenzoic acid). Thiocholine is the product of the enzymatic reaction between acetylthiocholine (ATCI) and ChE. The intensity of the color of the product measured colorimetrically allows the determination of changes in enzyme activity. In the presence of an inhibitor, the change is suppressed, and we observe a lower-intensity color or complete inhibition [48].
Ellman’s method, among others, was applied to study the inhibitory activity of hexane extracts of the roots of Archangelicae officinalis L. against AChE and BuChE using physostigmine as a standard and the following conditions: AChE (0.45 U mL−1) in Tris-HCl buffer (pH 7.8); incubation of the enzyme at 4 °C for t = 30 min; and incubation of the reaction mixture at 37 °C for 20 min, followed by measurements using an ELISA microplate reader (λ = 412 nm). A weak result of inhibition was achieved for AChE (Angelica root hexane extract (IC50 AChE = 315 ± 20 (µg mL−1) and fruit hexane extract (IC50 AChE = 73 ± 7 (µg mL−1)), but much higher inhibition was observed with regard to the BuChE root extract (IC50 BuChE = 16 ± 5 (µg mL−1)) and fruit hexane extract (IC50 BuChE = 9 ± 2 (µg mL−1)) [28].

4.2. Spectrophotometric Modification of Ellman’s Method

Ding et al. (2013) described a modification used to determine the inhibitory activity of flavonoids and ginkgolides B and C from the leaves of Ginkgo biloba against AChE and BuChE [111]. Only flavonoids inhibit AChE (results in Table 1). In the method of Park and Choi (1991), the supernatant from the brown planthopper maggot was prepared (which contains ChE) [110]; the homogenized supernatant (T = 4 °C, t = 30 min.) was prepared in phosphate buffer (pH = 7.0) and 0.1 % Triton X-100. Acetone solutions of the analyzed compounds and standard (chlorpyrifos) were mixed with the previously prepared solution containing the supernatant and analyzed in a 96-well microtiter plate after 1h. DTNB and ATCI were added. Then, the measurement of absorbance was performed (λ = 405 nm microplate reader). The activity is relative to the control reaction, assumed as 100 %, and to the test compounds replaced by the buffer. On the basis of the results, the IC50 was determined [110].
The spectrophotometric modification of Ellman’s method described by Senol et al. (2010) was used to verify the inhibition of the methanol extract and isolated compounds (imperatorin (17), xanthotoxin and bergapten) from the fruits of Angelica officinalis L. [99]. The inhibition of both cholinesterases was tested using an ELISA microplate reader; galanthamine (1) as a standard; AChE from electric eel; and BuChE from horse serum. The potent inhibition of BuChE was observed for both the extract (100 µg/mL—85.65 ± 1.49%) and each of the compounds (Table 1) [100]. Many of the compounds were tested by using various modifications of the spectrophotometric method; they differed in the incubation time, the equipment used, the concentration of reactants and the wavelength measurement. The inhibitors belong to different groups of compounds (Table 1).
Cholinesterase inhibitory activity was also identified by using a TLC technique. By comparing the methods performed using the microplate and TLC, as described in Rhee et al. (2001), it can be assumed that TLC methods are more sensitive [16]. Due to the advantages of the TLC approach (simple, inexpensive and accurate measurement), this review focuses on methods using this technique.

4.3. TLC Modification of Ellman’s Method

The modification of Ellman’s method has been described by Rhee et al. (2001) [16,48]. As a result of the disruption of ATCI by AChE, choline is formed, which constitutes a colored compound (5-thio-2-nitrobenzoate anion) with DTNB. The color intensity of the product is measured spectrophotometrically. The bands of the tested extract are developed on the TLC plate, and the band pattern is sprayed with a mixture of DTNB and then ATCI in Tris-HCl buffer (Trizma hydrochloride with bovine serum, pH = 8); the AChE enzyme is then applied (3 U mL−1; from electric eel). This results in a yellow background due to a diazo compound (5 min) with white trails, which indicates inhibition by the extract. The disadvantage of the method is the possibility of false-positive effects [16].
The modified method of Rhee et al. (2001) was used, inter alia, to evaluate the obtained compound (mahanimbine) and petroleum ether extract (10 mg mL−1)) from Murraya koenigii. The plates were developed with a mobile phase (petroleum ether: CHCl3, 50: 50 (v/v)) and, after drying, were sprayed with DTNB/ATCI, followed by the implementation of the basic method. The enzyme activity was measured using a 96-well microplate reader [16,48,76]. The procedure described by Rhee et al. (2001) was also used to investigate the inhibitory activity against ChE by the extract and compounds (10-hydroxy-infractopicrin and infractopicrin) isolated from the toadstool Cortinarius infractus. For the measurement, the following compounds were used: AChE from bovine erythrocytes or equine serum BuChE and tacrine, physostigmine and galanthamine (1) as standards (>100 µM). The results were determined using a 96-well microplate reader [61].

4.4. TLC Bioautography by Marston

A properly made plate with applied spots of extracts was sprayed with a prepared mixture with the enzyme AChE or BuChE (T = 4 °C in Tris-hydrochloric acid, pH = 7.8, with bovine serum albumin as a stabilizer) and incubated (T = 37 °C, 20 min; increased humidity).
Then, in order to carry out the detection, a mixture containing, inter alia, Fast Blue Salt and alpha-naphthyl acetate prepared ex tempore was sprayed. After incubation (1–2 min.), a purple background due to the diazonium dye was obtained, while white spots indicated inhibition caused by the applied sample. The clear differences in the background color and band color indicate inhibition [101].

4.5. TLC Bioautography by Mroczek

A TLC plate with spots of the tested extracts (appropriately prepared) and the standard (galanthamine (1)) was developed with an adequate mobile phase (here, CHCl3/MeOH/25 % NH4OH 8:1:1 v/v/v) containing 2-naphthyl acetate. After developing and thoroughly drying (10 min), the plate was sprayed with the prepared mixture containing AChE (3 U mL−1) in TRIS buffer (pH 7.8) and incubated (increased humidity, T = 37 °C).
Then, it was sprayed with a solution of Fast Blue B salt. White spots demonstrating inhibition were clearly visible on the dark purple background due to the azo compound and appeared quickly (1 min), and they were very persistent (for 24 h). The advantage of this method is the decreased usage of the enzyme and the shortened time required for its incubation (10 min) compared to other methods. The method is highly sensitive and fast [77].
This validation method was performed by the author for the determination of the inhibition of Amaryllidaceae AChE isolated from extracts from Narcissus jonquilla ‘Pipit’ and Narcissus jonquilla ‘Havera’ and purified extracts of N. jonquilla ‘Baby Moon’, Crinum moorei and Scadoxus puniceus. This procedure manages to achieve high sensitivity. The inhibitory activity of the isolated alkaloid was demonstrated, and it was indicated that dihydrogalanthamine has greater inhibition, approximately 42% higher than galanthamine (1) [77]. With the application of this method, the activity of alkaloids present in the extract from Argemone mexicana L. roots was proved; it was weak for magnoflorine and strong for berberine (7), palmatine and galanthamine (1), isolated for the first time from the Papaveraceae family [138]. Additionally, a two-dimensional thin-layer chromatography/high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry (TLC/HPLC/DAD/MS) system has been developed for both qualitative and quantitative analyses of active AChE inhibitors in plant samples [139]. The method of bioautography by Mroczek confirmed the inhibition of AChE by Amaryllidaceae alkaloids and determined their numerous occurrences in three cultivars of Narcissus: N. jonquilla ‘Baby Moon’, N. ‘Golden Ducat’ and N. ‘Cheerfulness’; the alkaloids were and identified both by using a TLC plate assay and by using TLC/HPLC/DAD/MS [140]. These methods have also been used to demonstrate AChE inhibitory activity and to qualitatively evaluate Lycopodiaceae alkaloids, and they were successfully used to study neuroprotective polyphenols from two species of Trifolium as well [141,142].

4.6. Fluorimetric Methods

These are fluorescent techniques (quenching) that measure enzyme–inhibitor binding affinities. This type of pathway has been chosen to demonstrate the activity of flavonoids from Paulownia tomentosa fruits with minor modifications to the spectrophotometric method of Ellman (1961). As a reference standard, physostigmine (eserine) was used (Table 1). In addition, using the fluorescence assay method (decrease), the affinity of the compounds with the relevant enzyme was studied.
The results were based on the dependency of the constant affinity rate, proportional to the inhibitory activity. Spectrophotometer measurements of the fluorescence emission were taken with a camera (M Series Multi-Mode Microplate Readers) (T = 18° and 37 °C) as the solution was titrated with a predetermined amount of a solution of hAChE (phosphate buffer (pH 8.0) (5 U mL−1)) with successive amounts of the tested flavonoids added. Studies have shown that the presence of a geranyl substituent at the C6 position in the structure of flavonoids is important for their ability to inhibit AChE [34].
The fluorimetric method was a part of the analysis of the Mangosteen seedcase extract outlined below [136]. To measure the compounds, the following steps were performed: the supernatant was centrifuged (12,000 rpm, 10 min.), a mixture with a buffer solution of ChE (5 μL) was added to the extract solution (20 μL), and the extract (CHCl3 in MeOH) was incubated (T = 37 °C, t = 30 min.). The supernatant (2 μL) was analyzed using ultra-performance liquid chromatography coupled with a photo-diode array detector and quadrupole time-of-flight mass spectrometry (UPLC/PDA/QTOF/MS), and the result was compared with that of the analysis without the enzyme. In the chromatogram, the peaks of mangostanol, allanxanthone E, gudraxanthone, γ-mangostin, 8-deoxygartanin and α-mangostin vanished (results in Table 1), so those compounds show an affinity for the enzyme. Then, the inhibitory activity of both cholinesterases was measured using a modification of Ellman’s method (Table 1). Using a fluorescence technique (quenching), affinity toward AChE was compared with γ-mangostin (Table 1) and 9-hydroxycalabaxanthone (IC50 > 100 µM). The first compound gained a much higher score. The authors supposed that the significant inhibition of AChE can respond to the presence of more than one prenyl group [136].
The methods presented in this review for determining cholinesterase inhibition by the investigated compounds can be described as qualitative and quantitative ones. Those based on the TLC technique (TLC bioautography) are more suitable for demonstrating inhibition by particular compounds (qualitative), and they are more sensitive compared to spectrophotometric methods (modifications of Ellman’s method). Nevertheless, they are not suitable for the determination of the inhibition coefficient, or it is difficult to measure. Therefore, they do not offer the possibility to compare the potency of inhibition among inhibitors. Both of these advantages are realized by methods based on a combination of the TLC technique (TLC bioautography) with more advanced techniques, such as HPLC/DAD/MS (high performance liquid chro-matography with photodiode array mass spectrometry), as mentioned in this article. Their use is increasingly observed in newer publications on cholinesterase inhibitors.

5. Conclusions

Reviewing the available publications, it can be concluded that methods for investigating cholinesterase inhibition have been mostly based on known procedures. These are generally modifications of previously used methods. They differ in parameters, which could affect the result of the activity of the enzyme and substrate, the incubation time, the method of analysis, the order of the addition of reactants and the type of assay.
It is important to study pure plant materials from respectively tested sources (heavy metal ions and detergents) and adequately purify the sample. The results (IC50) of the same compound when determined relative to hAChE and eeAChE can differ [136]. In some of the publications, the type of cholinesterase used in the study is not described or this information is difficult to obtain.
It is only possible to compare the IC50 values of specific compounds when determined under relatively similar conditions, using the same methods and compared to the same reference compound, thereby concluding potency. In most cases, one method is used, and results are rarely confirmed by using another method. An increased number of studies examining the inhibitory effects on both cholinesterases would be advantageous. It is beneficial to enhance the awareness and understanding of the subject of IChEs and activity measurement methods. Some of the studies did not include designations of activity toward both cholinesterases. It would be useful to use several reference substances in one study, which would allow for a better comparison of the available inhibition results.
However, more recent studies include the determination of the inhibition of both cholinesterases by the studied compounds and also attempt to analyze the structure and enzyme–inhibitor interaction, which is highly beneficial. This review reveals that inhibitors more potent than galanthamine (1), acting against both cholinesterases, are still being discovered. At the same time, compounds exhibiting potent selective activity against one of the cholinesterases have emerged. According to the established criteria in the study, strong activity against AChE was shown by 27 compounds, medium-strong was shown by 93 compounds, and weak activity was shown by 77 compounds, while against BuChE, strong, medium-strong and weak activity was shown by 43, 68 and 22 inhibitors, respectively. The largest group of compounds with a strong effect on both AChE and BuChE, as shown by the tabular comparison, were alkaloids. Compounds from this group demonstrated the most potent inhibition of AChE. Especially strong inhibition results against both cholinesterases were demonstrated for alkaloids from the Amaryllidaceae and Papaveraceae families. The most potent BuChE inhibition was demonstrated by compounds from various groups: alkaloids, coumarins, flavonoids, phenylpropanoids, polyphenols, phenanthrenes, phthalates, sterols and steroids, triterpenoids, xanthonoids and also lignans or phlorotannins. The presented review, as well as a summary of the results of the inhibitors’ structure analysis, may be beneficial in the determination and planning of further stages of research for the presented compounds. These data may also be helpful in the search and synthesis of new semi-synthetic or synthetic derivatives, as well as new biologically active substances.
Work on finding compound derivatives with more specific, preferable features that we find in plant materials has yielded positive results. The ability to modify them allows for even better parameters of the drug, such as greater activity, a better match to the receptor, mitigated side effects, a longer duration of action or a favorable method of production. The integration of phytochemistry and cooperative disciplines of molecular modeling and chemical synthesis provides an opportunity to find effective drugs. The studies conducted continuously demonstrate that compounds of natural origin are still abundant and carry a lot of possible solutions.
The observed persistent deficiency of effective therapies for neurological diseases, including AD, requires researchers to further search for new therapeutic substances. The presented review, conducted for the period from 2008 to 2022 years, shows that the search for and analysis of natural cholinesterase inhibitors have not been exhausted yet. After summarizing in vitro studies, the conclusion emerges that the potential for the use of cholinesterase inhibitors in therapeutics has not been fully explored. Only some of them have been tested in vivo, and for several of them, clinical studies have been attempted. The results presented in this publication indicate that natural sources are a huge reservoir in the search for new therapeutic substances, including cholinesterase inhibitors.

Author Contributions

N.S.-W.: writing—original draft preparation, conceptualization and data curation; T.M.: writing—review and editing, conceptualization and supervision. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

The authors thank Patrycja Nawratowicz for help in translating the review into English.

Conflicts of Interest

The authors declare no conflict of interest.

Abbreviations

AChAcetylcholine
AChEAcetylcholinesterase
ADAlzheimer’s disease
ATCIAcetylthiocholine
BuChEButyrylcholinesterase
ChECholinesterase
DTNB5,5′-Dithiobis-(2-nitrobenzoic acid)
eeAChEElectrophors electricus acetylcholinesterase
e.g., (lat. exempli gratia)For example
hAChEHuman erythrocyte acetylcholinesterase
IBuChEInhibitor of butyrylcholinesterase
IC50Inhibitory concentration for which enzyme activity is equal to half-maximal
IChEInhibitor of cholinesterases
SARStructure–activity relationship
TLC/HPLC/DAD/MSThin-layer chromatography/high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry
Tris-HClTrizma hydrochloride with bovine serum
UPLC-PDA-QTOF-MSUltra-performance liquid chromatography coupled with photo-diode array detector and quadrupole time-of-flight mass spectrometry
vs.Versus

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Figure 1. Chemical structures of galanthamine (1) and angustidine (2) and general structure of lycorine-type alkaloids (3).
Figure 1. Chemical structures of galanthamine (1) and angustidine (2) and general structure of lycorine-type alkaloids (3).
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Figure 2. Chemical structures of N-allyl-nor-galanthamine (4), N-(14-methylallyl)-nor-galanthamine (5) and sanguinine (6).
Figure 2. Chemical structures of N-allyl-nor-galanthamine (4), N-(14-methylallyl)-nor-galanthamine (5) and sanguinine (6).
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Figure 3. Chemical structures of berberine (7), dihydroberberine (8) and coptisine (9).
Figure 3. Chemical structures of berberine (7), dihydroberberine (8) and coptisine (9).
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Figure 4. Chemical structures of lycoparin A (10), lycoparin B (11) and lycoparin C (12).
Figure 4. Chemical structures of lycoparin A (10), lycoparin B (11) and lycoparin C (12).
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Figure 5. Chemical structures of coronaridine (13) and voacangine (14).
Figure 5. Chemical structures of coronaridine (13) and voacangine (14).
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Figure 6. Chemical structures of 6′-hydroxy-7′-methoxybergamottin (15) and 6′,7′- dihydroxybergamottin (16).
Figure 6. Chemical structures of 6′-hydroxy-7′-methoxybergamottin (15) and 6′,7′- dihydroxybergamottin (16).
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Figure 7. Chemical structures of imperatorin (17), heraclenol-2′-O-angelate (18), isoimperatorin (19) and byakangelicin-2′-O-angelate (20).
Figure 7. Chemical structures of imperatorin (17), heraclenol-2′-O-angelate (18), isoimperatorin (19) and byakangelicin-2′-O-angelate (20).
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Figure 8. Chemical structures of mesuagenin B (21) and 5,7-dihydroxy-8-(3-methylbutanoyl)-6-[(E)-3,7-dimethylocta-2,6-dienyl]-4-phenyl-2H-chromen-2-one (22). (*Stereochemistry not determined).
Figure 8. Chemical structures of mesuagenin B (21) and 5,7-dihydroxy-8-(3-methylbutanoyl)-6-[(E)-3,7-dimethylocta-2,6-dienyl]-4-phenyl-2H-chromen-2-one (22). (*Stereochemistry not determined).
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Figure 9. Chemical structures of (−)-alpininoid B (23), (4E)-1,7-diphenyl 4-hepten-3-one (24) and dihydroyashsbushiketol (25).
Figure 9. Chemical structures of (−)-alpininoid B (23), (4E)-1,7-diphenyl 4-hepten-3-one (24) and dihydroyashsbushiketol (25).
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Figure 10. General chemical structures of flavonoid (26), flavanone (27), flavonol (28) and isoflavone (29) rings.
Figure 10. General chemical structures of flavonoid (26), flavanone (27), flavonol (28) and isoflavone (29) rings.
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Figure 11. Chemical structures of diplacone (30), eriodictyol (31), 4′-O-methyldiplacol (32) and 4′-O-methyldiplacone (33).
Figure 11. Chemical structures of diplacone (30), eriodictyol (31), 4′-O-methyldiplacol (32) and 4′-O-methyldiplacone (33).
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Figure 12. Chemical structures of galangin (34), kaempferol (35) and rutin (36).
Figure 12. Chemical structures of galangin (34), kaempferol (35) and rutin (36).
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Figure 13. Chemical structures of 1-[(4-hydroxyphenyl)methyl]-4-methoxy-2,7-phenanthrenediol (37) and 1-(4-hydroxybenzyl)-4, 7-dimethoxyphenanthrene-2,8-diol (38).
Figure 13. Chemical structures of 1-[(4-hydroxyphenyl)methyl]-4-methoxy-2,7-phenanthrenediol (37) and 1-(4-hydroxybenzyl)-4, 7-dimethoxyphenanthrene-2,8-diol (38).
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Figure 14. Chemical structures of dihydrotanshinone I (39), cryptotanshinone (40), tanshinone I (41) and tanshinone IIA (42).
Figure 14. Chemical structures of dihydrotanshinone I (39), cryptotanshinone (40), tanshinone I (41) and tanshinone IIA (42).
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Figure 15. Chemical structures of bellidifolin (43), bellidin (44) and triptexanthoside C (45).
Figure 15. Chemical structures of bellidifolin (43), bellidin (44) and triptexanthoside C (45).
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Smyrska-Wieleba, N.; Mroczek, T. Natural Inhibitors of Cholinesterases: Chemistry, Structure–Activity and Methods of Their Analysis. Int. J. Mol. Sci. 2023, 24, 2722. https://doi.org/10.3390/ijms24032722

AMA Style

Smyrska-Wieleba N, Mroczek T. Natural Inhibitors of Cholinesterases: Chemistry, Structure–Activity and Methods of Their Analysis. International Journal of Molecular Sciences. 2023; 24(3):2722. https://doi.org/10.3390/ijms24032722

Chicago/Turabian Style

Smyrska-Wieleba, Natalia, and Tomasz Mroczek. 2023. "Natural Inhibitors of Cholinesterases: Chemistry, Structure–Activity and Methods of Their Analysis" International Journal of Molecular Sciences 24, no. 3: 2722. https://doi.org/10.3390/ijms24032722

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