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Molecules, Volume 16, Issue 9 (September 2011), Pages 7183-8142

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Research

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Open AccessArticle Identification of Dehydroxytrichostatin A as a Novel Up-Regulator of the ATP-Binding Cassette Transporter A1 (ABCA1)
Molecules 2011, 16(9), 7183-7198; doi:10.3390/molecules16097183
Received: 25 May 2011 / Revised: 24 June 2011 / Accepted: 25 July 2011 / Published: 25 August 2011
Cited by 9 | PDF Full-text (538 KB)
Abstract
The ATP-binding cassette transporter A1 (ABCA1) mediates the cellular efflux of excess cholesterol and phospholipids to lipid-poor apolipoprotein A-I (apoA-I). ABCA1 plays an important role in high-density lipoprotein (HDL) biogenesis and reverse cholesterol transport. By using a cell-based screening model for the ABCA1
[...] Read more.
The ATP-binding cassette transporter A1 (ABCA1) mediates the cellular efflux of excess cholesterol and phospholipids to lipid-poor apolipoprotein A-I (apoA-I). ABCA1 plays an important role in high-density lipoprotein (HDL) biogenesis and reverse cholesterol transport. By using a cell-based screening model for the ABCA1 up-regulator and column chromatography, an active compound, 9179B, was isolated. Through analysis of its NMR data, 9179B was identified as dehydroxytrichostatin A. We found that 9179B increased the transcription of ABCA1 in a cell-based reporter assay, with an EC50 value of 2.65 μM. 9179B up-regulated ABCA1 expression at both mRNA and protein levels in HepG2 and RAW264.7 cells. It also up-regulated the expression of scavenger receptor class B type I (SR-BI) as well as the uptake of DiI-HDL in RAW264.7 cells. This compound stimulated ApoA-I-mediated cellular cholesterol efflux from RAW 264.7 cells. We further found that 9179B was a potent histone deacetylase (HDAC) inhibitor with an IC50 value of 0.08 μM. Reporter gene assays showed that the regulation of ABCA1 transcription by 9179B was mainly mediated by the −171/−75 bp promoter region. Together, our results indicate that 9179B is an ABCA1 up-regulator and dehydroxytrichostatin A may be a novel anti-atherogenic compound. Full article
(This article belongs to the collection Bioactive Compounds)
Open AccessArticle Chirality and Numbering of Substituted Tropane Alkaloids
Molecules 2011, 16(9), 7199-7209; doi:10.3390/molecules16097199
Received: 12 July 2011 / Revised: 16 August 2011 / Accepted: 17 August 2011 / Published: 25 August 2011
Cited by 6 | PDF Full-text (554 KB)
Abstract
The strict application of IUPAC rules for the numbering of tropane alkaloids is not always applied by authors and there is hence a lot of confusion in the literature. In most cases, the notation of 3, 6/7-disubstituted derivatives has been chosen arbitrarily, based
[...] Read more.
The strict application of IUPAC rules for the numbering of tropane alkaloids is not always applied by authors and there is hence a lot of confusion in the literature. In most cases, the notation of 3, 6/7-disubstituted derivatives has been chosen arbitrarily, based on NMR and MS data, without taking into account the absolute configuration of these two carbons. This paper discusses the problem and the relevance of CD and NMR to determine molecular configurations. We report on the use of 1H-NMR anisochrony (Δd) induced by the Mosher’s chiral auxiliary reagents (R)-(-)- and (S)-(+)-α-methoxy-α-trifluoromethyl-phenylacetyl chlorides (MTPA-Cl), to determine the absolute configuration of (3R,6R)-3α-hydroxy-6b-senecioyloxytropane, a disubstituted tropane alkaloid isolated from the aerial parts of Schizanthus grahamii (Solanaceae). These analytical tools should help future works in correctly assigning the configuration of additional 3, 6/7 disubstituted tropane derivatives. Full article
(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)
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Open AccessArticle Effect of ASP2151, a Herpesvirus Helicase-Primase Inhibitor, in a Guinea Pig Model of Genital Herpes
Molecules 2011, 16(9), 7210-7223; doi:10.3390/molecules16097210
Received: 26 July 2011 / Revised: 4 August 2011 / Accepted: 22 August 2011 / Published: 25 August 2011
Cited by 15 | PDF Full-text (551 KB)
Abstract
ASP2151 is a herpesvirus helicase-primase inhibitor with antiviral activity against varicella zoster virus and herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). Here, we examined the potency and efficacy of ASP2151 against HSV in vitro and in vivo. We found that
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ASP2151 is a herpesvirus helicase-primase inhibitor with antiviral activity against varicella zoster virus and herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). Here, we examined the potency and efficacy of ASP2151 against HSV in vitro and in vivo. We found that ASP2151 was more potent in inhibiting the replication of HSV-1 and HSV-2 in Vero cells in the plaque reduction assay and had greater anti-HSV activity in a guinea pig model of genital herpes than did acyclovir and valacyclovir (VACV), respectively. Oral ASP2151 given from the day of infection reduced peak and overall disease scores in a dose-dependent manner, resulting in complete prevention of symptoms at the dose of 30 mg/kg. The 50% effective dose (ED50) values for ASP2151 and VACV were 0.37 and 68 mg/kg, respectively, indicating that ASP2151 was 184-fold more potent than VACV. When ASP2151 was administered after the onset of symptoms, the disease course of genital herpes was suppressed more effectively than by VACV, with a significant reduction in disease score observed one day after starting ASP2151 at 30 mg/kg, whereas the therapeutic effect of VACV was only evident three days after treatment at the highest dose tested (300 mg/kg). This indicated that ASP2151 possesses a faster onset of action and wider therapeutic time window than VACV. Further, virus shedding from the genital mucosa was significantly reduced with ASP2151 at 10 and 30 mg/kg but not with VACV, even at 300 mg/kg. Taken together, our present findings demonstrated the superior potency and efficacy of ASP2151 against HSV. Full article
(This article belongs to the Special Issue Antivirals)
Open AccessArticle Flow Injection Spectrophotometric Determination of N-Acetyl-L-cysteine as a Complex with Palladium(II)
Molecules 2011, 16(9), 7224-7236; doi:10.3390/molecules16097224
Received: 18 July 2011 / Revised: 16 August 2011 / Accepted: 17 August 2011 / Published: 25 August 2011
Cited by 10 | PDF Full-text (622 KB)
Abstract
We describe a new method using flow-injection analysis with spectro-photometric detection, suitable for the determination of N-acetyl-L-cysteine (NAC). The proposed method is appropriate for the determination of NAC in reaction with Pd2+ ions in the concentration range from 1.0 × 10
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We describe a new method using flow-injection analysis with spectro-photometric detection, suitable for the determination of N-acetyl-L-cysteine (NAC). The proposed method is appropriate for the determination of NAC in reaction with Pd2+ ions in the concentration range from 1.0 × 10−5 mol L−1 to 6.0 × 10−5 mol L−1. The detection limit NAC was 5.84 × 10−6 mol L−1 and the recorded relative standard deviation of the method is in the range from 1.67 to 4.11%. NAC and Pd2+ form complexes of Pd2+:NAC molar ratios of 1:1 and 1:2, depending on the ratio of their analytical concentrations. The cumulative conditional stability constant for the Pd(NAC)22+ complex is β12' = 2.69 × 109 L2 mol2. The proposed method was compared with the classic spectrophotometric determination of NAC, using the same reagent, PdCl2, and had shown certain advantages: a) shorter analysis time; b) the use of smaller volumes of sample and reagents, which make the proposed method cheaper and faster for NAC determination in real samples without sample pretreatment. Full article
(This article belongs to the Special Issue Flow Chemistry)
Open AccessArticle Synthesis of Silver Nanoparticles in Chitosan, Gelatin and Chitosan/Gelatin Bionanocomposites by a Chemical Reducing Agent and Their Characterization
Molecules 2011, 16(9), 7237-7248; doi:10.3390/molecules16097237
Received: 23 June 2011 / Revised: 20 July 2011 / Accepted: 3 August 2011 / Published: 25 August 2011
Cited by 60 | PDF Full-text (1564 KB)
Abstract
In this research, silver nanoparticles (AgNPs) were synthesized in chitosan (Cts), Cts/gelatin and gelatin suspensions using a chemical reducing agent. Cts and gelatin were used as natural stabilizers and solid support, whereas AgNO3 was used as the silver precursor. Sodium borohydride (NaBH
[...] Read more.
In this research, silver nanoparticles (AgNPs) were synthesized in chitosan (Cts), Cts/gelatin and gelatin suspensions using a chemical reducing agent. Cts and gelatin were used as natural stabilizers and solid support, whereas AgNO3 was used as the silver precursor. Sodium borohydride (NaBH4) was used as the reducing agent. The properties of AgNPs in Cts, Cts/gelatin and gelatin bionanocomposites (BNCs) were studied in terms of their surface plasmon resonance, crystalline structure, average diameter size, particle distributions, surface topography and functional groups. All the samples were characterized by UV-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy. Full article
Open AccessArticle A Novel Cyclodione Coumarin from the Stem Bark of Mesua beccariana
Molecules 2011, 16(9), 7249-7255; doi:10.3390/molecules16097249
Received: 19 July 2011 / Revised: 1 August 2011 / Accepted: 15 August 2011 / Published: 25 August 2011
Cited by 4 | PDF Full-text (492 KB)
Abstract
Our ongoing investigations on the stem bark of Mesua beccariana afforded a novel cyclodione coumarin, beccamarin, together with two known xanthones, mesuarianone, mesuasinone, two anthraquinones, 4-methoxy-1,3,5-trihydroxy-anthraquinone and 2,5-dihydroxy-1,3,4-trimethoxyanthraquinone and one coumarin, mammea A/AB. The structures were elucidated by 1D and 2D NMR
[...] Read more.
Our ongoing investigations on the stem bark of Mesua beccariana afforded a novel cyclodione coumarin, beccamarin, together with two known xanthones, mesuarianone, mesuasinone, two anthraquinones, 4-methoxy-1,3,5-trihydroxy-anthraquinone and 2,5-dihydroxy-1,3,4-trimethoxyanthraquinone and one coumarin, mammea A/AB. The structures were elucidated by 1D and 2D NMR and MS techniques. Full article
(This article belongs to the Special Issue Coumarins and Xanthones)
Open AccessArticle Use of Graphite Oxide and Graphene Oxide as Catalysts in the Synthesis of Dipyrromethane and Calix[4]pyrrole
Molecules 2011, 16(9), 7256-7266; doi:10.3390/molecules16097256
Received: 6 July 2011 / Revised: 17 August 2011 / Accepted: 19 August 2011 / Published: 25 August 2011
Cited by 24 | PDF Full-text (391 KB)
Abstract Graphite oxide and graphene oxides have been used as solid catalysts for the synthesis of 5,5-dialkyldipyrromethanes and calix[4]pyrroles in organic and aqueous solutions at room temperature. Full article
(This article belongs to the Section Organic Synthesis)
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Open AccessArticle Cyclization vs. Cyclization/Dimerization in o-Amidostilbene Radical Cation Cascade Reactions: The Amide Question
Molecules 2011, 16(9), 7267-7287; doi:10.3390/molecules16097267
Received: 5 August 2011 / Revised: 16 August 2011 / Accepted: 17 August 2011 / Published: 25 August 2011
Cited by 3 | PDF Full-text (922 KB) | Supplementary Files
Abstract
The n-butyramido, isobutyramido, benzamido, and furancarboxamido functions profoundly modulate the electronics of the stilbene olefinic and NH groups and the corresponding radical cations in ways that influence the efficiency of the cyclization due presumably to conformational and stereoelectronic factors. For example, isobutyramido-
[...] Read more.
The n-butyramido, isobutyramido, benzamido, and furancarboxamido functions profoundly modulate the electronics of the stilbene olefinic and NH groups and the corresponding radical cations in ways that influence the efficiency of the cyclization due presumably to conformational and stereoelectronic factors. For example, isobutyramido- stilbene undergoes FeCl3 promoted cyclization to produce only indoline, while n-butyramidostilbene, under the same conditions, produces both indoline and bisindoline. Full article
(This article belongs to the Section Organic Synthesis)
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Open AccessArticle Development of a Process for Separation of Mogroside V from Siraitia grosvenorii by Macroporous Resins
Molecules 2011, 16(9), 7288-7301; doi:10.3390/molecules16097288
Received: 1 July 2011 / Revised: 15 August 2011 / Accepted: 16 August 2011 / Published: 25 August 2011
Cited by 6 | PDF Full-text (495 KB)
Abstract
A separation method was developed for the preparative separation and enrichment of the non-caloric sweetener mogroside V from Siraitia grosvenorii. The adsorption properties of six macroporous resins were evaluated. Results showed that HZ 806 resin offered the best adsorption and desorption capacities.
[...] Read more.
A separation method was developed for the preparative separation and enrichment of the non-caloric sweetener mogroside V from Siraitia grosvenorii. The adsorption properties of six macroporous resins were evaluated. Results showed that HZ 806 resin offered the best adsorption and desorption capacities. Based on the adsorption experiments on HZ 806, the adsorption data were found to fit the Freundlich model well. The pseudo-second-order kinetic model showed the highest correlation with the experimental results. Separation was performed with deionized water and 40% aqueous ethanol solution as mobile phases. In a typical run, 100 g of herb was processed and 3.38 g of mogroside V with a purity of 10.7% was harvested. This separation method provided a 15.1-fold increase in the purification factor from 0.5% to 10.7%. The present study showed that HZ 806 resins were effective for the separation and enrichment of mogroside V from S. grosvenorii. Full article
Open AccessArticle Antioxidant and Antimicrobial Attributes and Phenolics of Different Solvent Extracts from Leaves, Flowers and Bark of Gold Mohar [Delonix regia (Bojer ex Hook.) Raf.]
Molecules 2011, 16(9), 7302-7319; doi:10.3390/molecules16097302
Received: 29 June 2011 / Revised: 31 July 2011 / Accepted: 4 August 2011 / Published: 25 August 2011
Cited by 42 | PDF Full-text (465 KB)
Abstract
This paper describes the antioxidant and antimicrobial activities and phenolic components of different solvent (absolute methanol, absolute ethanol, absolute acetone, 80% methanol, 80% ethanol, 80% acetone and deionized water) extracts of leaves, flowers and bark of Gold Mohar [Delonix regia (Bojer ex
[...] Read more.
This paper describes the antioxidant and antimicrobial activities and phenolic components of different solvent (absolute methanol, absolute ethanol, absolute acetone, 80% methanol, 80% ethanol, 80% acetone and deionized water) extracts of leaves, flowers and bark of Gold Mohar [Delonix regia (Bojer ex Hook.) Raf.]. The extract yields from leaves, flowers and bark ranged from 10.19 to 36.24, 12.97 to 48.47 and 4.22 to 8.48 g/100 g dry weight (DW), respectively. Overall, 80% methanol extract produced from the leaves exhibited significantly (P < 0.05) higher antioxidant activity, with high phenolic contents (3.63 g GAE/100 g DW), total flavonoid contents (1.19 g CE/100 g DW), inhibition of peroxidation (85.54%), DPPH scavenging capacity (IC50 value 8.89 μg/mL) and reducing power (1.87). Similarly, this 80% methanol leaves extract also showed superior antimicrobial activity. HPLC analysis of the 80% methanol extracts for individual phenolics revealed the presence of gallic, protocatechuic and salicylic acid in leaves; gallic, protocatechuic, salicylic, trans-cinnamic and chlorogenic acid in flowers, and gallic acid in bark as the main (amount > 1.50 mg/100 g DW) phenolic acids. Besides, small amounts ( < 1.50 mg/100 g DW) of some other phenolic acids such as sorbic, sinapic, p-coumaric, m-coumaric, ferulic, caffeic, 3-hydroxybenzoic, 4-hydroxycinnamic and 4-hydroxybenzoic acids were also detected. The extracts of the tested parts of Gold Mohar, especially, the leaves, might be valuable for functional food and therapeutic applications. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Toxicity of Rhododendron anthopogonoides Essential Oil and Its Constituent Compounds towards Sitophilus zeamais
Molecules 2011, 16(9), 7320-7330; doi:10.3390/molecules16097320
Received: 11 July 2011 / Revised: 15 August 2011 / Accepted: 16 August 2011 / Published: 25 August 2011
Cited by 16 | PDF Full-text (420 KB)
Abstract
The screening of several Chinese medicinal plants for insecticidal principles showed that essential oil of Rhododendron anthopogonoides flowering aerial parts possessed significant toxicity against maize weevils, Sitophilus zeamais. A total of 37 components were identified in the essential oil and the main
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The screening of several Chinese medicinal plants for insecticidal principles showed that essential oil of Rhododendron anthopogonoides flowering aerial parts possessed significant toxicity against maize weevils, Sitophilus zeamais. A total of 37 components were identified in the essential oil and the main constituents of the essential oil were 4-phenyl-2-butanone (27.22%), nerolidol (8.08%), 1,4-cineole (7.85%), caryophyllene (7.63%) and γ-elemene (6.10%), followed by α-farnesene (4.40%) and spathulenol (4.19%). Repeated bioactivity-directed chromatographic separation on silica gel columns led us to isolate three compounds, namely 4-phenyl-2-butanone, 1,4-cineole, and nerolidol. 4-Phenyl-2-butanone shows pronounced contact toxicity against S. zeamais (LD50 = 6.98 mg/adult) and was more toxic than either 1,4-cineole or nerolidol (LD50 = 50.86 mg/adult and 29.30 mg/adult, respectively) against the maize weevils, while the crude essential oil had a LD50 value of 11.67 mg/adult. 4-Phenyl-2-butanone and 1,4-cineole also possessed strong fumigant toxicity against the adults of S. zeamais (LC50 = 3.80 mg/L and 21.43 mg/L) while the crude essential oil had a LC50 value of 9.66 mg/L. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Interaction of α-Melanocortin and Its Pentapeptide Antisense LVKAT: Effects on Hepatoprotection in Male CBA Mice
Molecules 2011, 16(9), 7331-7343; doi:10.3390/molecules16097331
Received: 26 July 2011 / Revised: 23 August 2011 / Accepted: 23 August 2011 / Published: 26 August 2011
Cited by 8 | PDF Full-text (548 KB)
Abstract
The genetic code defines nucleotide patterns that code for individual amino acids and their complementary, i.e., antisense, pairs. Peptides specified by the complementary mRNAs often bind to each other with a higher specificity and efficacy. Applications of this genetic code property in
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The genetic code defines nucleotide patterns that code for individual amino acids and their complementary, i.e., antisense, pairs. Peptides specified by the complementary mRNAs often bind to each other with a higher specificity and efficacy. Applications of this genetic code property in biomedicine are related to the modulation of peptide and hormone biological function, selective immunomodulation, modeling of discontinuous and linear epitopes, modeling of mimotopes, paratopes and antibody mimetics, peptide vaccine development, peptidomimetic and drug design. We have investigated sense-antisense peptide interactions and related modulation of the peptide function by modulating the effects of a-MSH on hepatoprotection with its antisense peptide LVKAT. First, transcription of complementary mRNA sequence of a-MSH in 3’→5’ direction was used to design antisense peptide to the central motif that serves as a-MSH pharmacophore for melanocortin receptors. Second, tryptophan spectrofluorometric titration was applied to evaluate the binding of a-MSH and its central pharmacophore motif to the antisense peptide, and it was concluded that this procedure represents a simple and efficient method to evaluate sense-antisense peptide interaction in vitro. Third, we showed that antisense peptide LVKAT abolished potent hepatoprotective effects of a-MSH in vivo. Full article
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Open AccessArticle Evaluation of the Effects of Mitragyna speciosa Alkaloid Extract on Cytochrome P450 Enzymes Using a High Throughput Assay
Molecules 2011, 16(9), 7344-7356; doi:10.3390/molecules16097344
Received: 4 July 2011 / Revised: 8 August 2011 / Accepted: 19 August 2011 / Published: 29 August 2011
Cited by 22 | PDF Full-text (492 KB)
Abstract
The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi
[...] Read more.
The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi method. As compared with the liquid chromatography-mass spectrometry method, this method has shown to be a fast and cost-effective way to perform CYP inhibition studies. The results indicated that MSE has the most potent inhibitory effect on CYP3A4 and CYP2D6, with apparent half-maximal inhibitory concentration (IC50) values of 0.78 µg/mL and 0.636 µg/mL, respectively. In addition, moderate inhibition was observed for CYP1A2, with an IC50 of 39 µg/mL, and weak inhibition was detected for CYP2C19. The IC50 of CYP2C19 could not be determined, however, because inhibition was < 50%. Competitive inhibition was found for the MSE-treated CYP2D6 inhibition assay, whereas non-competitive inhibition was shown in inhibition assays using CYP3A4, CYP1A2 and CYP2C19. Quinidine (CYP2D6), ketoconazole (CYP3A4), tranylcypromine (CYP2C19) and furafylline (CYP1A2) were used as positive controls throughout the experiments. This study shows that MSE may contribute to an herb-drug interaction if administered concomitantly with drugs that are substrates for CYP3A4, CYP2D6 and CYP1A2. Full article
(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)
Open AccessArticle Antibacterial Activity of Aristolochia brevipes against Multidrug-Resistant Mycobacterium tuberculosis
Molecules 2011, 16(9), 7357-7364; doi:10.3390/molecules16097357
Received: 20 July 2011 / Revised: 18 August 2011 / Accepted: 23 August 2011 / Published: 29 August 2011
Cited by 8 | PDF Full-text (353 KB)
Abstract
The increased incidence of Multidrug-Resistant Mycobacterium tuberculosis (MDR-MT) requires the search for alternative antimycobacterial drugs. The main aim of this study was to evaluate the dichloromethane extract from Aristolochia brevipes (Rhizoma) and the compounds isolated from this extract against several mycobacterial strains, sensitive,
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The increased incidence of Multidrug-Resistant Mycobacterium tuberculosis (MDR-MT) requires the search for alternative antimycobacterial drugs. The main aim of this study was to evaluate the dichloromethane extract from Aristolochia brevipes (Rhizoma) and the compounds isolated from this extract against several mycobacterial strains, sensitive, resistant (monoresistant), and clinical isolates (multidrug-resistant), using the alamarBlue™ microassay. The extract was fractionated by column chromatography, yielding the following eight major compounds: (1) 6α-7-dehydro-N-formylnornantenine; (2) E/Z-N-formylnornantenine; (3) 7,9-dimethoxytariacuripyrone; (4) 9-methoxy-tariacuripyrone; (5) aristololactam I; (6) β-sitosterol; (7) stigmasterol; and (8) 3-hydroxy-α-terpineol. The structures of these compounds were elucidated by 1H- and 13C- (1D and 2D) Nuclear Magnetic Resonance (NMR) spectroscopy. This study demonstrates that the dichloromethane extract (rhizome) of A. brevipes possesses strong in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (Minimum Inhibitory Concentration value [MIC], 12.5 µg/mL). The most active compound against all mycobacterial strains tested was the compound aristolactam I (5), with MIC values ranging between 12.5 and 25 µg/mL. To our knowledge, this the first report of antimycobacterial activity in this plant. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle An Emulsion Based Microarray Method to Detect the Toxin Genes of Toxin-Producing Organisms
Molecules 2011, 16(9), 7365-7376; doi:10.3390/molecules16097365
Received: 21 July 2011 / Revised: 12 August 2011 / Accepted: 25 August 2011 / Published: 29 August 2011
Cited by 2 | PDF Full-text (1023 KB)
Abstract
Toxins produced by bacteria and fungi are one of the most important factors which may cause food contamination. The study of detection methods with high sensitivity and throughput is significant for the protection of food safety. In the present study, we coupled microarray
[...] Read more.
Toxins produced by bacteria and fungi are one of the most important factors which may cause food contamination. The study of detection methods with high sensitivity and throughput is significant for the protection of food safety. In the present study, we coupled microarray with emulsion PCR and developed a high throughput detection method. Thirteen different gene sites which encode the common toxins of several bacteria and fungi were assayed in parallel in positive and maize samples. Conventional PCR assays were carried out for comparison. The results showed that the developed microarray method had high specificity and sensitivity. Two zearalenone-related genes were investigated in one of the ten maize samples obtained with this present method. The results indicated that the emulsion based microarray detection method was developed successfully and suggested its potential application in multiple gene site detection. Full article
Open AccessArticle A Practical Approach to New (5Z) 2-Alkylthio-5-arylmethylene-1-methyl-1,5-dihydro-4H-imidazol-4-one Derivatives
Molecules 2011, 16(9), 7377-7390; doi:10.3390/molecules16097377
Received: 13 July 2011 / Revised: 25 August 2011 / Accepted: 22 August 2011 / Published: 30 August 2011
Cited by 3 | PDF Full-text (456 KB)
Abstract A practical protocol for the preparation of (5Z)-2-alkylthio-5-arylmethylene-1-methyl-1,5-dihydro-4H-imidazol-4-one derivatives is reported. The new compounds were obtained in good yield and stereoselectivity in two steps, namely a solvent-free Knoevenagel condensation under microwave irradiation, followed by an S-alkylation reaction with various halogenoalkanes. Full article
(This article belongs to the Section Organic Synthesis)
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Open AccessArticle Microwave-Assisted Extraction of Oxymatrine from Sophora flavescens
Molecules 2011, 16(9), 7391-7400; doi:10.3390/molecules16097391
Received: 22 June 2011 / Revised: 15 August 2011 / Accepted: 16 August 2011 / Published: 30 August 2011
Cited by 4 | PDF Full-text (381 KB)
Abstract
In this paper, microwave-assisted extraction (MAE) of oxymatrine from Sophora flavescens were studied by HPLC-photodiode array detection. Effects of several experimental parameters, such as concentration of extraction solvent, ratio of liquid to material, microwave power, extraction temperature, and extraction time on the extraction
[...] Read more.
In this paper, microwave-assisted extraction (MAE) of oxymatrine from Sophora flavescens were studied by HPLC-photodiode array detection. Effects of several experimental parameters, such as concentration of extraction solvent, ratio of liquid to material, microwave power, extraction temperature, and extraction time on the extraction efficiencies of oxymatrine were evaluated. The optimal extraction conditions were 60% ethanol, a 20:1 (v/v) ratio of liquid to material and extraction for 10 min at 50 °C under 500 W microwave irradiation. Under the optimum conditions, the yield of oxymatrine was 14.37 mg/g. The crude extract obtained could be used as either a component of some complex traditional medicines or for further isolation and purification of bioactive compounds. The results, which indicated that MAE is a very useful tool for the extraction of important phytochemicals from plant materials, should prove helpful for the full utilization of Sophora flavescens. Full article
Open AccessArticle Antioxidant Capacity of Ocimum basilicum L. and Origanum vulgare L. Extracts
Molecules 2011, 16(9), 7401-7414; doi:10.3390/molecules16097401
Received: 9 August 2011 / Revised: 25 August 2011 / Accepted: 26 August 2011 / Published: 30 August 2011
Cited by 26 | PDF Full-text (503 KB)
Abstract
The antioxidant properties of five different extracts (Et2O, CHCl3, EtOAc, n-BuOH, and H2O) of Ocimum basilicum L. and Origanum vulgare L. were studied. Antioxidant activity was assessed in six different model systems. Free radical scavenging capacity
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The antioxidant properties of five different extracts (Et2O, CHCl3, EtOAc, n-BuOH, and H2O) of Ocimum basilicum L. and Origanum vulgare L. were studied. Antioxidant activity was assessed in six different model systems. Free radical scavenging capacity (RSC) was evaluated by measuring the scavenging capacity of extracts on DPPH, NO, O2·- and OH radical, as well as on hydrogen peroxide (H2O2). In addition, the protective effects on lipid peroxidation in liposomes (LPx) were evaluated by TBA-assay using the Fe2+/ascorbate induction system. The amount of total phenolic compounds and content of total flavonoids was also determined. EtOAc, n-BuOH and H2O extracts of O. basilicum and O. vulgare expressed very strong scavenger activity. Furthermore, the mentioned extracts showed notable inhibition of LPx. On the other hand, Et2O and CHCl3 extracts showed much weaker effect in the neutralization of DPPH, NO and O2·- radicals and the neutralization of H2O2. When examining the production of OH radicals and inhibition of LPx, the Et2O and CHCl3 extracts showed weak prooxidative properties. The observed differences in antioxidant activity could be partially explained by the levels of phenolics and flavonoids in the investigated O. basilicum and O. vulgare extracts. Full article
(This article belongs to the Special Issue Radical Chemistry)
Open AccessArticle Acute Toxicity and Hepatotoxicokinetic Studies of Tamarindus indica Extract
Molecules 2011, 16(9), 7415-7427; doi:10.3390/molecules16097415
Received: 2 August 2011 / Revised: 24 August 2011 / Accepted: 29 August 2011 / Published: 31 August 2011
PDF Full-text (195 KB)
Abstract
Tamarindus indica is widely used as a food and beverage and in traditional medicine. The apparent lack of dose standardization in herbal medicine necessitates the evaluation of the lethality T. indica on Artemia salina nauplii and chicken embryos via in vitro and
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Tamarindus indica is widely used as a food and beverage and in traditional medicine. The apparent lack of dose standardization in herbal medicine necessitates the evaluation of the lethality T. indica on Artemia salina nauplii and chicken embryos via in vitro and in vivo techniques. Furthermore, hepatotoxicokinetics of the crude extract and fractions on Wister rats was also assessed. At concentrations of 200, 20 and 2 µg/mL, crude extract and fractions showed brine shrimp death percentages ranging from 86.70% to 3.30% and the sub-fractions showed death percentage ranges of 46.70% to 3.30%. Calculated LD50 values ranged from 832 µg/mL to 5,019 µg/mL. Dosing Wister rats with 25% and 50% concentration of LD50 determined for crude extract and fractions on chicken embryos showed an elevation in the ALT and AST levels in the serum. Brine shrimps and chicken embryos showed a positive correlation, with R2 values of 0.541 and 0.588 (P ≤ 0.05) for fractions and subfractions, respectively, as media for the lethality assay. Dose standardization in folk herbal medicine is imperative as T. indica used as food and medicine has been shown to be toxic at high doses. Brine shrimp and chicken embryos may be comparably used as medium for toxicity assay. Full article
Open AccessArticle Mathematical Evaluation of the Amino Acid and Polyphenol Content and Antioxidant Activities of Fruits from Different Apricot Cultivars
Molecules 2011, 16(9), 7428-7457; doi:10.3390/molecules16097428
Received: 10 August 2011 / Accepted: 17 August 2011 / Published: 1 September 2011
Cited by 23 | PDF Full-text (3401 KB) | Supplementary Files
Abstract
Functional foods are of interest because of their significant effects on human health, which can be connected with the presence of some biologically important compounds. In this study, we carried out complex analysis of 239 apricot cultivars (Prunus armeniaca L.) cultivated in
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Functional foods are of interest because of their significant effects on human health, which can be connected with the presence of some biologically important compounds. In this study, we carried out complex analysis of 239 apricot cultivars (Prunus armeniaca L.) cultivated in Lednice (climatic area T4), South Moravia, Czech Republic. Almost all previously published studies have focused only on analysis of certain parameters. However, we focused on detection both primary and secondary metabolites in a selection of apricot cultivars with respect to their biological activity. The contents of thirteen biogenic alpha-L-amino acids (arginine, asparagine, isoleucine, lysine, serine, threonine, valine, leucine, phenylalanine, tryptophan, tyrosine, proline and alanine) were determined using ion exchange chromatography with UV-Vis spectrometry detection. Profile of polyphenols, measured as content of ten polyphenols with significant antioxidant properties (gallic acid, procatechinic acid, p-aminobenzoic acid, chlorogenic acid, caffeic acid, vanillin, p-coumaric acid, rutin, ferrulic acid and quercetrin), was determined by high performance liquid chromatography with spectrometric/electrochemical detection. Moreover, content of total phenolics was determined spectrophotometrically using the Folin-Ciocalteu method. Antioxidant activity was determined using five independent spectrophotometric methods: DPPH assay, DMPD method, ABTS method, FRAP and Free Radicals methods. Considering the complexity of the obtained data, they were processed and correlated using bioinformatics techniques (cluster analysis, principal component analysis). The studied apricot cultivars were clustered according to their common biochemical properties, which has not been done before. The observed similarities and differences were discussed. Full article
Open AccessArticle t-Bu2SiF-Derivatized D2-Receptor Ligands: The First SiFA-Containing Small Molecule Radiotracers for Target-Specific PET-Imaging
Molecules 2011, 16(9), 7458-7479; doi:10.3390/molecules16097458
Received: 28 July 2011 / Revised: 19 August 2011 / Accepted: 31 August 2011 / Published: 2 September 2011
Cited by 11 | PDF Full-text (616 KB)
Abstract
The synthesis, radiolabeling and in vitro evaluation of new silicon-fluoride acceptor (SiFA) derivatized D2-receptor ligands is reported. The SiFA-technology simplifies the introduction of fluorine-18 into target specific biomolecules for Positron-Emission-Tomography (PET). However, one of the remaining challenges, especially for small molecules
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The synthesis, radiolabeling and in vitro evaluation of new silicon-fluoride acceptor (SiFA) derivatized D2-receptor ligands is reported. The SiFA-technology simplifies the introduction of fluorine-18 into target specific biomolecules for Positron-Emission-Tomography (PET). However, one of the remaining challenges, especially for small molecules such as receptor-ligands, is the bulkiness of the SiFA-moiety. We therefore synthesized four Fallypride SiFA-conjugates derivatized either directly at the benzoic acid ring system (SiFA-DMFP, SiFA-FP, SiFA-DDMFP) or at the butyl-side chain (SiFA-M-FP) and tested their receptor affinities. We found D2-receptor affinities for all compounds in the nanomolar range (Ki(SiFA-DMFP) = 13.6 nM, Ki(SiFA-FP) = 33.0 nM, Ki(SiFA-DDMFP) = 62.7 nM and Ki(SiFA-M-FP) = 4.21 nM). The radiofluorination showed highest yields when 10 nmol of the precursors were reacted with [18F]fluoride/TBAHCO3 in acetonitrile. After a reversed phased cartridge purification the desired products could be isolated as an injectable solution after only 10 min synthesis time with radiochemical yields (RCY) of more than 40% in the case of SiFA-DMFP resulting in specific activities >41 GBq/µmol (>1,100 Ci/mmol). Furthermore, the radiolabeled products were shown to be stable in the injectable solutions, as well as in human plasma, for at least 90 min. Full article
(This article belongs to the Special Issue Fluorine Chemistry 2016)
Open AccessArticle Application of Preparative High-Speed Counter-Current Chromatography for the Separation of Two Alkaloids from the Roots of Tabernaemontana catharinensis (Apocynaceae)
Molecules 2011, 16(9), 7480-7487; doi:10.3390/molecules16097480
Received: 28 June 2011 / Revised: 16 August 2011 / Accepted: 31 August 2011 / Published: 2 September 2011
Cited by 5 | PDF Full-text (544 KB)
Abstract
The methanolic extract of Tabernaemontana catharinensis (Apocynaceae) roots, which contains alkaloids with several biological activities, was separated on a preparative scale using high-speed counter-current chromatography. The optimum solvent system was found to be a mixture of CHCl3-MeOH-H2O [5:10:6 (
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The methanolic extract of Tabernaemontana catharinensis (Apocynaceae) roots, which contains alkaloids with several biological activities, was separated on a preparative scale using high-speed counter-current chromatography. The optimum solvent system was found to be a mixture of CHCl3-MeOH-H2O [5:10:6 (v/v/v)] and led to a successful separation of two monoterpenic indole alkaloids, voachalotine (1) and 12-methoxy-Nb-methylvoachalotine (2) in approximately 4.0 hours. The alkaloids were all isolated at purities over 95%, and their structures were established on the basis of spectroscopic methods, including 1D and 2D NMR and EI/MS. Full article
(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)
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Open AccessArticle Thermal and Rheological Properties of a Family of Botryosphaerans Produced by Botryosphaeria rhodina MAMB-05
Molecules 2011, 16(9), 7488-7501; doi:10.3390/molecules16097488
Received: 12 July 2011 / Revised: 18 August 2011 / Accepted: 23 August 2011 / Published: 2 September 2011
Cited by 3 | PDF Full-text (412 KB)
Abstract
Differential scanning calorimetry (DSC), thermogravimetry (TG) and Fourier-transform infra-red spectroscopy (FT-IR) analyses were performed to investigate changes in the physico-chemical properties of botryosphaerans, a family of exopolysaccharides (EPS) produced by the fungus Botryosphaeria rhodina MAMB-05 grown on glucose (EPSGLC), sucrose (EPS
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Differential scanning calorimetry (DSC), thermogravimetry (TG) and Fourier-transform infra-red spectroscopy (FT-IR) analyses were performed to investigate changes in the physico-chemical properties of botryosphaerans, a family of exopolysaccharides (EPS) produced by the fungus Botryosphaeria rhodina MAMB-05 grown on glucose (EPSGLC), sucrose (EPSSUC) and fructose (EPSFRU). A slight endothermic transition and small mass loss attributable to the removal of water of hydration were observed in the DSC and TG analyses, respectively, for the three EPS samples. The FT-IR spectra confirmed no structural changes occurred during thermal treatment. Viscometry was utilized to obtain information on the rheological behaviour of the EPS in aqueous solutions. The Power Law and Cross Equations determined the natural pseudoplastic characteristics of the EPS. Comparatively, results obtained for EPS produced when B. rhodina MAMB-05 was grown on each of the three carbohydrate sources demonstrated similar apparent viscosity values for EPSGLC and EPSSUC, while EPSFRU displayed the lowest apparent viscosity of the three botryosphaerans, suggesting a higher degree of ramification and lower Mw. EPSGLC and EPSSUC possessed similar degrees of ramification. The slight differences found in their viscosities can be explained by the differences in the type of branching among the three botryosphaerans, thus varying the strength of intermolecular interactions and consequently, consistency and viscosity. The physico-chemical studies of botryosphaerans represent the originality of this work, and the knowledge of these properties is an important criterion for potential applications. Full article
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Open AccessArticle Bioactivity of Carica papaya (Caricaceae) against Spodoptera frugiperda (Lepidoptera: Noctuidae)
Molecules 2011, 16(9), 7502-7509; doi:10.3390/molecules16097502
Received: 14 July 2011 / Revised: 6 August 2011 / Accepted: 25 August 2011 / Published: 2 September 2011
Cited by 8 | PDF Full-text (354 KB)
Abstract
The composition of a chloroform seed extract of C. papaya was determined by GC-MS. Nineteen compounds were identified, with oleic (45.97%), palmitic (24.1%) and stearic (8.52%) acids being the main components. The insecticidal and insectistatic activities of the extract and the three main
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The composition of a chloroform seed extract of C. papaya was determined by GC-MS. Nineteen compounds were identified, with oleic (45.97%), palmitic (24.1%) and stearic (8.52%) acids being the main components. The insecticidal and insectistatic activities of the extract and the three main constituents were tested. Larval duration increased by 3.4 d and 2.5 d when the extract was used at 16,000 and 9,600 ppm, respectively, whereas the pupal period increased by 2.2 d and 1.1 d at the same concentrations. Larval viability values were 0%, 29.2%, and 50% when the extract was applied at 24,000, 16,000, and 9,600 ppm, respectively; pupal viability was 42.9% and 66.7% at 16,000 and 9,600 ppm; and pupal weight decreased by 25.4% and 11.5% at 16,000 and 9,600 ppm. The larval viability of the main compounds was 33.3%, 48.5%, and 62.5% when exposed to 1,600 ppm of palmitic acid, oleic acid, or stearic acid, respectively. Full article
Open AccessArticle Antioxidant, Anti-Lipoxygenase and Cytotoxic Activity of Leptadenia pyrotechnica (Forssk.) Decne Polyphenolic Constituents
Molecules 2011, 16(9), 7510-7521; doi:10.3390/molecules16097510
Received: 7 May 2011 / Revised: 23 August 2011 / Accepted: 28 August 2011 / Published: 5 September 2011
Cited by 9 | PDF Full-text (388 KB)
Abstract
Leptadenia pyrotechnica Forssk is a traditional medicinal herb used for treatment of inflammatory diseases and cancer. In this research, the aqueous ethanolic crude extract of Leptadenia pyrotechnica aerial parts, along with its ethyl acetate, n-butanol and water partitioning fractions were evaluated for
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Leptadenia pyrotechnica Forssk is a traditional medicinal herb used for treatment of inflammatory diseases and cancer. In this research, the aqueous ethanolic crude extract of Leptadenia pyrotechnica aerial parts, along with its ethyl acetate, n-butanol and water partitioning fractions were evaluated for their antioxidant capacity, polyphenolic content, anti-inflammatory and anti-cancer properties. The total antioxidant capacity was estimated by the FRAP, DPPH, ABTS and β-carotene bleaching assays.The ethyl acetate fraction exhibited the highest polyphenolic content (252.27 mg gallic acid/g) and the best antioxidant activity (1.2, 0.57, 0.45 mmol ascorbic acid equivalent/g in the FRAP, ABTS and DPPH assays, respectively). Furthermore, the same extract showed appreciable anti-inflammatory via lipoxygenase (LOX) inhibitory activity (IC50 = 1.41 µg/mL). Moreover, the ethyl acetate fraction also showed the strongest cytotoxic effect (IC50 = 43.16 µg/mL) against MCF-7 human breast cancer cell line. These results suggest that this plant may be considered an interesting source of compounds with antioxidant, anti-inflammatory and anti-cancer properties for therapeutic, nutraceutical and functional food applications. Full article
Open AccessArticle Synthesis and SAR Study of Novel Peptide Aldehydes as Inhibitors of 20S Proteasome
Molecules 2011, 16(9), 7551-7564; doi:10.3390/molecules16097551
Received: 1 August 2011 / Revised: 29 August 2011 / Accepted: 30 August 2011 / Published: 5 September 2011
Cited by 8 | PDF Full-text (557 KB)
Abstract
Based on the analysis of the crystal structure of MG101 (1) and 20S proteasomes, a new series of peptide aldehyde derivatives were designed and synthesized. Their ability to inhibit 20S proteasome was assayed. Among them, Cbz-Glu(OtBu)-Phe-Leucinal (3c),
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Based on the analysis of the crystal structure of MG101 (1) and 20S proteasomes, a new series of peptide aldehyde derivatives were designed and synthesized. Their ability to inhibit 20S proteasome was assayed. Among them, Cbz-Glu(OtBu)-Phe-Leucinal (3c), Cbz-Glu(OtBu)-Leu-Leucinal (3d), and Boc-Ser(OBzl)-Leu-Leucinal (3o) exhibited the most activity, which represented an order of magnitude enhancement compared with MG132 (2). The covalent docking protocol was used to explore the binding mode. The structure-activity relationship of the peptide aldehyde inhibitors is discussed. Full article
Open AccessArticle 1,3-Substituted Imidazolidine-2,4,5-triones: Synthesis and Inhibition of Cholinergic Enzymes
Molecules 2011, 16(9), 7565-7582; doi:10.3390/molecules16097565
Received: 16 August 2011 / Revised: 30 August 2011 / Accepted: 31 August 2011 / Published: 5 September 2011
Cited by 12 | PDF Full-text (756 KB) | Supplementary Files
Abstract
A series of novel and highly active acetylcholinesterase and butyrylcholinesterase inhibitors derived from substituted benzothiazoles containing an imidazolidine-2,4,5-trione moiety were synthesized and characterized. The molecular structure of 1-(2,6-diisopropyl-phenyl)-3-[(1R)-1-(6-fluoro-1,3-benzothiazol-2-yl)ethyl]-imidazolidine-2,4,5-trione (3g) was determined by single-crystal X-ray diffraction. Both optical isomers are
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A series of novel and highly active acetylcholinesterase and butyrylcholinesterase inhibitors derived from substituted benzothiazoles containing an imidazolidine-2,4,5-trione moiety were synthesized and characterized. The molecular structure of 1-(2,6-diisopropyl-phenyl)-3-[(1R)-1-(6-fluoro-1,3-benzothiazol-2-yl)ethyl]-imidazolidine-2,4,5-trione (3g) was determined by single-crystal X-ray diffraction. Both optical isomers are present as two independent molecules in the triclinic crystal system. The lipophilicity of the compounds was determined as the partition coefficient log Kow using the traditional shake-flask method. The in vitro inhibitory activity on acetylcholinesterase from electric eel and butyrylcholinesterase isolated from equine serum was determined. The inhibitory activity on acetylcholinesterase was significantly higher than that of the standard drug rivastigmine. The discussed compounds are also promising inhibitors of butyrylcholinesterase, as some of the prepared compounds inhibit butyrylcholinesterase better than the internal standards rivastigmine and galanthamine. The highest inhibitory activity (IC50 = 1.66 μmol/L) corresponds to the compound 1-(4-isopropylphenyl)-3-[(R)-1-(6-fluorobenzo[d]thiazol-2-yl)ethyl]imidazolidine-2,4,5-trione (3d). For all the studied compounds, the relationships between the lipophilicity and the chemical structure as well as their structure-activity relationships are discussed. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle Bioassay-Directed Isolation of Active Compounds with Antiyeast Activity from a Cassia fistula Seed Extract
Molecules 2011, 16(9), 7583-7592; doi:10.3390/molecules16097583
Received: 2 July 2011 / Accepted: 15 August 2011 / Published: 5 September 2011
Cited by 20 | PDF Full-text (797 KB)
Abstract
Background and objective: Cassia fistula L belongs to the family Leguminosae, and it is one of the most popular herbal products in tropical countries. C. fistula seeds have been used as a herbal medicine and have pharmacological activity which includes anti-bacterial, anti-fungal,
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Background and objective: Cassia fistula L belongs to the family Leguminosae, and it is one of the most popular herbal products in tropical countries. C. fistula seeds have been used as a herbal medicine and have pharmacological activity which includes anti-bacterial, anti-fungal, and antioxidant properties. The goal of this study was to identify compounds from C. fistula seeds which are responsible for anti-Candida albicans activity using bioassay-directed isolation. Results: The preliminary phytochemical screening of the plant seed revealed the presence of anthraquinones, flavonoids, saponins, tannins and terpenoids. The isolation of active compounds was carried out in four steps: multiple extractions, fractionation using column chromatography and purification using preparative thin-layer chromatography (TLC) and liquid chromatography/mass spectrometry (LC/MS). The structure of separated compounds was determined on the basis of mass spectrometry data. One compound was identified is roseanone. Conclusions: The MS analysis on the active fraction from seed extract of C. fistula confirmed the presence of roseanone with antiyeast activity. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Synthesis, Spectroscopic Properties and Antipathogenic Activity of New Thiourea Derivatives
Molecules 2011, 16(9), 7593-7607; doi:10.3390/molecules16097593
Received: 4 August 2011 / Revised: 29 August 2011 / Accepted: 1 September 2011 / Published: 6 September 2011
Cited by 27 | PDF Full-text (453 KB)
Abstract
A number of acylthioureas, 2-((4-methylphenoxy)methyl)-N-(aryl-carbamothioyl)benzamides (aryl = 3,5-dichlorophenyl, 2,3-dichlorophenyl, 3,4-dichloro-phenyl, 2,4,5-trichlorophenyl, 3,4,5-trichlorophenyl, 2-bromophenyl, 2,4-dibromophenyl, 2,5-dibromophenyl, 2-iodophenyl, 3-fluorophenyl, 2,3,4-trifluorophenyl, 2,4,5-trifluoro-phenyl, 2,4,6-trifluorophenyl) have been synthesized, characterized by elemental analysis, IR and NMR spectroscopy and tested for their interaction with bacterial cells in free
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A number of acylthioureas, 2-((4-methylphenoxy)methyl)-N-(aryl-carbamothioyl)benzamides (aryl = 3,5-dichlorophenyl, 2,3-dichlorophenyl, 3,4-dichloro-phenyl, 2,4,5-trichlorophenyl, 3,4,5-trichlorophenyl, 2-bromophenyl, 2,4-dibromophenyl, 2,5-dibromophenyl, 2-iodophenyl, 3-fluorophenyl, 2,3,4-trifluorophenyl, 2,4,5-trifluoro-phenyl, 2,4,6-trifluorophenyl) have been synthesized, characterized by elemental analysis, IR and NMR spectroscopy and tested for their interaction with bacterial cells in free and adherent state. The anti-pathogenic activity was correlated with the presence of one iodine, bromide or fluorine, and two or three chloride atoms on the N-phenyl substituent of the thiourea moiety, being significant especially on Pseudomonas aeruginosa and Staphylococcus aureus strains, known for their ability to grow in biofilms. Our results demonstrate the potential of these derivatives for further development of novel anti-microbial agents with antibiofilm properties. Full article
Open AccessArticle Studies on the Electrochemical Behavior of Thiazolidine and Its Applications Using a Flow–Through Chronoamperometric Sensor Based on a Gold Electrode
Molecules 2011, 16(9), 7608-7620; doi:10.3390/molecules16097608
Received: 21 July 2011 / Revised: 30 August 2011 / Accepted: 1 September 2011 / Published: 6 September 2011
PDF Full-text (1295 KB)
Abstract
The electrochemical behaviors of thiazolidine (tetrahydrothiazole) on gold and platinum electrodes were investigated in a Britton-Robinson buffer (pH 2.77–11.61), acetate buffer (pH 4.31), phosphate buffer solutions (pH 2.11 and 6.38) and methanol or acetonitrile containing various supporting electrolytes. Detection was based on a
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The electrochemical behaviors of thiazolidine (tetrahydrothiazole) on gold and platinum electrodes were investigated in a Britton-Robinson buffer (pH 2.77–11.61), acetate buffer (pH 4.31), phosphate buffer solutions (pH 2.11 and 6.38) and methanol or acetonitrile containing various supporting electrolytes. Detection was based on a gold wire electrochemical signal obtained with a supporting electrolyte containing 20% methanol-1.0 mM of phosphate buffer (pH 6.87, potassium dihydrogen phosphate and dipotassium hydrogen phosphate) as the mobile phase. Comparison with results obtained with a commercial amperometric detector shows good agreement. Using the chronoamperometric sensor with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.05 to 16 mg L−1 was found. The limit of quantification (LOQ) of the method for thiazolidine was found to be 1 ng. Full article
(This article belongs to the Special Issue Gold Catalysts)
Open AccessCommunication Synthesis of No-Carrier-Added 4-[18F]Fluorophenol from 4-Benzyloxyphenyl-(2-thienyl)iodonium Bromide
Molecules 2011, 16(9), 7621-7626; doi:10.3390/molecules16097621
Received: 11 August 2011 / Revised: 24 August 2011 / Accepted: 31 August 2011 / Published: 6 September 2011
Cited by 7 | PDF Full-text (402 KB)
Abstract
4-[18F]Fluorophenol is a versatile synthon for the synthesis of more complex radiopharmaceuticals bearing a 4-[18F]fluorophenoxy moiety. In order to prepare 4-[18F]fluorophenol in no-carrier-added (n.c.a.) form only a nucleophilic labelling method starting from [18F]fluoride is suitable.
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4-[18F]Fluorophenol is a versatile synthon for the synthesis of more complex radiopharmaceuticals bearing a 4-[18F]fluorophenoxy moiety. In order to prepare 4-[18F]fluorophenol in no-carrier-added (n.c.a.) form only a nucleophilic labelling method starting from [18F]fluoride is suitable. In this paper a new, two step radiosynthesis starting from 4-benzyloxyphenyl-(2-thienyl)iodonium bromide and [18F]fluoride with subsequent deprotection is described, yielding n.c.a. [18F]fluorophenol in 34 to 36% radiochemical yield. Full article
(This article belongs to the Special Issue Fluorine Chemistry 2016)
Open AccessCommunication Synthesis and Structural Characterization of 1-[2-(5-Nitro-1H-indol-2-yl)phenyl]methylpyridinium Chloride
Molecules 2011, 16(9), 7627-7633; doi:10.3390/molecules16097627
Received: 29 July 2011 / Revised: 22 August 2011 / Accepted: 25 August 2011 / Published: 6 September 2011
Cited by 1 | PDF Full-text (484 KB)
Abstract
In the course of studies on hybrid antibacterials incorporating 2-aryl-5-nitro-1H-indole moieties as potential bacterial NorA efflux pump inhibitors, the compound 1-[2-(5-nitro-1H-indol-2-yl)phenyl]methylpyridinium chloride (2) was synthesized and structurally characterized. This pyridinium chloride salt crystallized in the monoclinic space
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In the course of studies on hybrid antibacterials incorporating 2-aryl-5-nitro-1H-indole moieties as potential bacterial NorA efflux pump inhibitors, the compound 1-[2-(5-nitro-1H-indol-2-yl)phenyl]methylpyridinium chloride (2) was synthesized and structurally characterized. This pyridinium chloride salt crystallized in the monoclinic space group P21/c with the following unit cell dimensions: a 10.274(3) Å, b 13.101(4) Å, c 13.439(4) Å, b 107.702(7)°, V 1723.2(9) Å3, Z (f.u.) = 4; R1 = 0.048, and wR2 = 0.13. Of interest in the single crystal X-ray structure is the (intramolecular) disposition of the pyridinium plane over the indole heterocyclic residue [interplanar dihedral angle 17.91(4)°]. Full article
Open AccessArticle A Novel Anti-Inflammatory Role for Ginkgolide B in Asthma via Inhibition of the ERK/MAPK Signaling Pathway
Molecules 2011, 16(9), 7634-7648; doi:10.3390/molecules16097634
Received: 19 July 2011 / Revised: 11 August 2011 / Accepted: 16 August 2011 / Published: 6 September 2011
Cited by 25 | PDF Full-text (1061 KB)
Abstract
Ginkgolide B is an anti-inflammatory extract of Ginkgo biloba and has been used therapeutically. It is a known inhibitor of platelet activating factor (PAF), which is important in the pathogenesis of asthma. Here, a non-infectious mouse model of asthma is used to evaluate
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Ginkgolide B is an anti-inflammatory extract of Ginkgo biloba and has been used therapeutically. It is a known inhibitor of platelet activating factor (PAF), which is important in the pathogenesis of asthma. Here, a non-infectious mouse model of asthma is used to evaluate the anti-inflammatory capacity of ginkgolide B (GKB) and characterize the interaction of GKB with the mitogen activated protein kinase (MAPK) pathway. BALB/c mice that were sensitized and challenged to ovalbumin (OVA) were treated with GKB (40 mg/kg) one hour before they were challenged with OVA. Our study demonstrated that GKB may effectively inhibit the increase of T-helper 2 cytokines, such as interleukin (IL)-5 and IL-13 in bronchoalveolar lavage fluid (BALF). Furthermore, the eosinophil count in BALF significantly decreased after treatment of GKB when compared with the OVA-challenged group. Histological studies demonstrated that GKB substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. These results suggest that ginkgolide B may be useful for the treatment of asthma and its efficacy is related to suppression of extracellular regulating kinase/MAPK pathway. Full article
Open AccessArticle Synthesis of Quinolin-2-one Alkaloid Derivatives and Their Inhibitory Activities against HIV-1 Reverse Transcriptase
Molecules 2011, 16(9), 7649-7661; doi:10.3390/molecules16097649
Received: 16 June 2011 / Revised: 4 August 2011 / Accepted: 20 August 2011 / Published: 7 September 2011
Cited by 8 | PDF Full-text (592 KB)
Abstract
Based on an established common pharmacophore of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNTTIs), a series of quinolin-2-one derivatives were synthesized and assayed for their in vitro activities against HIV-1 reverse transcriptase (RT) for the first time. Some of the tested compounds were active
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Based on an established common pharmacophore of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNTTIs), a series of quinolin-2-one derivatives were synthesized and assayed for their in vitro activities against HIV-1 reverse transcriptase (RT) for the first time. Some of the tested compounds were active against HIV-1 RT. Compounds 4a2 and 4d2 showed inhibitory activities with IC50 values of 0.21 and 0.15 mM, respectively, with a mode of interaction with RT residues of the allosteric pocket similar to that of efavirenz. Full article
(This article belongs to the Special Issue Antivirals)
Open AccessArticle Synthesis of Some Oxadiazole Derivatives as New Anticandidal Agents
Molecules 2011, 16(9), 7662-7671; doi:10.3390/molecules16097662
Received: 25 July 2011 / Revised: 23 August 2011 / Accepted: 6 September 2011 / Published: 7 September 2011
Cited by 9 | PDF Full-text (462 KB)
Abstract
In this study, 5-[(pyrimidin-2-ylthio)methyl]-1,3,4-oxadiazole-2(3H)-thione (3) was synthesized via the ring closure reaction of 2-(pyrimidin-2-ylthio)acetohydrazide (2) with carbon disulphide. New oxadiazole derivatives 4a-f were obtained by the nucleophilic substitution reaction of compound 3 with various phenacyl bromides. The chemical structures
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In this study, 5-[(pyrimidin-2-ylthio)methyl]-1,3,4-oxadiazole-2(3H)-thione (3) was synthesized via the ring closure reaction of 2-(pyrimidin-2-ylthio)acetohydrazide (2) with carbon disulphide. New oxadiazole derivatives 4a-f were obtained by the nucleophilic substitution reaction of compound 3 with various phenacyl bromides. The chemical structures of the compounds were elucidated by IR, 1H-NMR, 13C-NMR and FAB+-MS spectral data and elemental analyses. The newly synthesized derivatives 4a-f were tested in vitro by using a microbroth dilution method against C. albicans (clinical isolate, Osmangazi University, Faculty of Medicine, Eskişehir, Turkey), C. albicans (ATCC 90028), C. glabrata (clinical isolate, Osmangazi University, Faculty of Medicine, Eskişehir, Turkey), C. tropicalis (NRRL Y-12968), C. krusei (NRRL Y-7179), C. parapsilosis (NRRL Y- 12696), C. albicans (NRRL Y-12983), C. glabrata (clinical isolate, Anadolu University, Faculty of Science, Department of Biology, Eskişehir, Turkey). Among these compounds, compound 4a was found to be the most potent derivative (MIC = 0.007–0.06 versus ketoconazole: 0.001–0.007 mg/mL) against Candida species, except C. tropicalis and C. krusei when compared with the standard antifungal ketoconazole. Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessArticle Antioxidant and Antiacetylcholinesterase Activities of Some Commercial Essential Oils and Their Major Compounds
Molecules 2011, 16(9), 7672-7690; doi:10.3390/molecules16097672
Received: 1 August 2011 / Revised: 29 August 2011 / Accepted: 2 September 2011 / Published: 7 September 2011
Cited by 44 | PDF Full-text (493 KB)
Abstract
The commercial essential oils of Citrus aurantium L., Cupressus sempervirens L., Eucalyptus globulus Labill., Foeniculum vulgare Mill. and Thymus vulgaris L., isolated by steam distillation by a company of Morocco were evaluated in terms of in vitro antioxidant activity through several methods. In
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The commercial essential oils of Citrus aurantium L., Cupressus sempervirens L., Eucalyptus globulus Labill., Foeniculum vulgare Mill. and Thymus vulgaris L., isolated by steam distillation by a company of Morocco were evaluated in terms of in vitro antioxidant activity through several methods. In vitro acetylcholinesterase inhibitory activity was also determined. Citrus limon (L.) Burm. f. oil was also studied, but it was obtained by peel expression. The best antioxidant was T. vulgaris oil, independent of the method used, mainly due to the presence of the phenolic monoterpenes thymol and carvacrol, which when studied as single compounds also presented the best activities. Concerning the acetylcholinesterase inhibition activity, E. globulus was the most effective. Nevertheless its main components 1,8-cineole and limonene were not the most active, a feature that corresponded to d-3-carene. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Synthesis and Transformations of di-endo-3-Aminobicyclo-[2.2.2]oct-5-ene-2-carboxylic Acid Derivatives
Molecules 2011, 16(9), 7691-7705; doi:10.3390/molecules16097691
Received: 18 July 2011 / Revised: 24 August 2011 / Accepted: 6 September 2011 / Published: 7 September 2011
Cited by 6 | PDF Full-text (454 KB)
Abstract
all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13) and all-endo-5-amino-6-(hydroxymethyl)bicyclo[2.2.2]octan-2-ol (10) were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2). Ring closure of b-amino ester
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all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13) and all-endo-5-amino-6-(hydroxymethyl)bicyclo[2.2.2]octan-2-ol (10) were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2). Ring closure of b-amino ester 4 resulted in tricyclic pyrimidinones 15 and 16. The structures, stereochemistry and relative configurations of the synthesized compounds were determined by IR and NMR. Full article
(This article belongs to the Section Molecular Diversity)
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Open AccessArticle Synthesis and Chemical Characterisation of Some New Diheteroaryl Thienothiophene Derivatives
Molecules 2011, 16(9), 7706-7714; doi:10.3390/molecules16097706
Received: 10 June 2011 / Revised: 15 August 2011 / Accepted: 5 September 2011 / Published: 8 September 2011
Cited by 10 | PDF Full-text (478 KB)
Abstract Treatment of 1-(5-acetyl-3,4-dimethythieno[2,3-b]thiophene-2yl)ethanone (1) with dimethylformamide dimethyl acetal afforded enaminone derivative 2, which reacted with amino derivatives to give the corresponding bis-pyrimidine, bis-pyrazole, bis-triazolo-pyrimidine and bis-benzoimidazopyrimidine derivatives. Full article
Open AccessArticle Crystal Structure and Density Functional Theory Study on Structural Properties and Energies of a Isonicotinohydrazide Compound
Molecules 2011, 16(9), 7715-7724; doi:10.3390/molecules16097715
Received: 28 July 2011 / Revised: 3 September 2011 / Accepted: 3 September 2011 / Published: 8 September 2011
Cited by 5 | PDF Full-text (604 KB) | Supplementary Files
Abstract
An X-ray and a theoretical study of the structure of the isoniazid derivative N'-(4-dimethylaminobenzylidene)-isonicotinohydrazide monohydrate (1) are reported. In this work, we will report a combined experimental and theoretical study on the molecular structure, vibrational spectra and energies of N'
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An X-ray and a theoretical study of the structure of the isoniazid derivative N'-(4-dimethylaminobenzylidene)-isonicotinohydrazide monohydrate (1) are reported. In this work, we will report a combined experimental and theoretical study on the molecular structure, vibrational spectra and energies of N'-(4-dimethylaminobenzylidene)-isonicotinohydrazide monohydrate. The calculated parameters are in good agreement with the corresponding X-ray diffraction values. The FTIR spectrum in the range of 400–4000 cm−1 of N'-(4-dimethylaminobenzylidene)-isonicotinohydrazide monohydrate has been recorded. The molecular geometry and vibrational frequencies and energies in the ground state are calculated by using the DFT (B3LYP, PBE1PBE) methods with 6-311G** basis sets. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. The geometries and normal modes of vibrations obtained from B3LYP/PBE1PBE/6-311G** calculations are in good agreement with the experimentally observed data. Full article
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Open AccessArticle Chemical Composition and Possible in Vitro Phytotoxic Activity of Helichrsyum italicum (Roth) Don ssp. italicum
Molecules 2011, 16(9), 7725-7735; doi:10.3390/molecules16097725
Received: 25 July 2011 / Revised: 30 August 2011 / Accepted: 6 September 2011 / Published: 8 September 2011
Cited by 10 | PDF Full-text (317 KB)
Abstract
The chemical composition of the essential oil of Helichrysum italicum (Roth) Don ssp. italicum, collected in the National Park of Cilento and Diano Valley, Southern Italy, was studied by means of GC and GC/MS. Forty four compounds of 45 constituents were
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The chemical composition of the essential oil of Helichrysum italicum (Roth) Don ssp. italicum, collected in the National Park of Cilento and Diano Valley, Southern Italy, was studied by means of GC and GC/MS. Forty four compounds of 45 constituents were identified in the oil, mainly oxygenated sesquiterpenes. The essential oil was evaluated for its potential in vitro phytotoxic activity against germination and early radicle elongation of radish and garden cress. The radicle elongation of radish was significantly inhibited at the highest doses tested, while germination of both seeds was not affected. Full article
Open AccessArticle Synthesis and in Vitro Antimicrobial Activity of Some Pyrazolyl-1-carboxamide Derivatives
Molecules 2011, 16(9), 7736-7745; doi:10.3390/molecules16097736
Received: 13 August 2011 / Revised: 25 August 2011 / Accepted: 31 August 2011 / Published: 9 September 2011
Cited by 11 | PDF Full-text (430 KB)
Abstract
A series of 3,5-disubstituted pyrazole-1-carboxamides were obtained by treatment of chalcones with semicarbazide hydrochloride in dioxane containing sodium acetate/acetic acid as a buffer solution. N-acetyl derivatives of pyrazole-1-carboxamides were isolated in good yields either by treatment of the carboxamide derivatives with acetic anhydride
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A series of 3,5-disubstituted pyrazole-1-carboxamides were obtained by treatment of chalcones with semicarbazide hydrochloride in dioxane containing sodium acetate/acetic acid as a buffer solution. N-acetyl derivatives of pyrazole-1-carboxamides were isolated in good yields either by treatment of the carboxamide derivatives with acetic anhydride or refluxing chalcones with semicarbazide in ethanol containing few drops of acetic acid to give the corresponding hydrazones. Subsequent treatment of hydrazones with acetic anhydride gave the desired N-acetyl pyrazole-1-carboxamides derivatives. When chalcones were refluxed with dioxane containing few drops of acetic acid, 4,5-dihydropyrazole-1-carboxamides were isolated, which were subsequently oxidized using 5% sodium hypochlorite in dioxane to afford pyrazole-1-carboxamides. The structures of isolated compounds were confirmed by elemental analyses and spectral methods. The isolated compounds were tested for their antimicrobial activities. Full article
(This article belongs to the Special Issue Heterocycles)
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Open AccessArticle Stopped-Flow Spectrophotometric Study of the Kinetics and Mechanism of CO2 Uptake by cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ Cation and the Acid-Catalyzed Decomposition of cis-[Cr(C2O4)(BaraNH2)OCO2] Anion in Aqueous Solution
Molecules 2011, 16(9), 7746-7761; doi:10.3390/molecules16097746
Received: 1 August 2011 / Revised: 1 September 2011 / Accepted: 6 September 2011 / Published: 9 September 2011
Cited by 3 | PDF Full-text (535 KB)
Abstract
The kinetics of CO2 uptake by the cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ complex cation and the acid hydrolysis of the cis-[Cr(C2O4)(BaraNH2)OCO2] complex anion (where
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The kinetics of CO2 uptake by the cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ complex cation and the acid hydrolysis of the cis-[Cr(C2O4)(BaraNH2)OCO2] complex anion (where BaraNH2 denotes methyl 3-amino-2,3-dideoxy-b-D-arabino-hexopyranoside) were studied using the stopped-flow technique. The reactions under study were investigated in aqueous solution in the 288–308 K temperature range. In the case of the reaction between CO2 and cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ cation variable pH values (6.82–8.91) and the constant ionic strength of solution (H+, Na+, ClO4 = 1.0) were used. Carbon dioxide was generated by the reaction between sodium pyruvate and hydrogen peroxide. The acid hydrolysis of cis-[Cr(C2O4)(BaraNH2)OCO2] was investigated for varying concentrations of H+ ions (0.01–2.7 M). The obtained results enabled the determination of the number of steps of the studied reactions. Based on the kinetic equations, rate constants were determined for each step. Finally, mechanisms for both reactions were proposed and discussed. Based on the obtained results it was concluded that the carboxylation (CO2 uptake) reactions of cis-[Cr(C2O4)(BaraNH2)(OH2)2]+ and the decarboxylation (acid hydrolysis) of the cis-[Cr(C2O4)(BaraNH2)OCO2] are the opposite of each other. Full article
(This article belongs to the Special Issue Flow Chemistry)
Open AccessArticle Physicochemical Properties, in Vitro Antioxidant Activities and Inhibitory Potential against α-Glucosidase of Polysaccharides from Ampelopsis grossedentata Leaves and Stems
Molecules 2011, 16(9), 7762-7772; doi:10.3390/molecules16097762
Received: 1 July 2011 / Revised: 28 August 2011 / Accepted: 8 September 2011 / Published: 9 September 2011
Cited by 8 | PDF Full-text (266 KB)
Abstract
In the present study, polysaccharides named ALPS and ASPS were isolated from Ampelopsis grossedentata leaves and stems, respectively. Physicochemical properties, in vitro antioxidant activities and the inhibitory effects on α-glucosidase of ALPS and ASPS were investigated. It was found that both ALPS and
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In the present study, polysaccharides named ALPS and ASPS were isolated from Ampelopsis grossedentata leaves and stems, respectively. Physicochemical properties, in vitro antioxidant activities and the inhibitory effects on α-glucosidase of ALPS and ASPS were investigated. It was found that both ALPS and ASPS were acid protein-bound heteropolysaccharides, although with considerably different chemical composition and molecular weight distribution. Meanwhile, in comparison with ALPS, ASPS exhibited stronger antioxidant activity and inhibitory potential against α-glucosidase according to the in vitro evaluation. Moreover, our results suggested that protein and uronic acid might, at least partly, contribute positively to the biological behavior of ALPS and ASPS. Full article
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Open AccessArticle Chemical, Antioxidant and Antimicrobial Investigations of Pinus cembra L. Bark and Needles
Molecules 2011, 16(9), 7773-7788; doi:10.3390/molecules16097773
Received: 4 August 2011 / Revised: 4 September 2011 / Accepted: 8 September 2011 / Published: 13 September 2011
Cited by 23 | PDF Full-text (448 KB)
Abstract
The chemical constituents and biological activity of Pinus cembra L. (Pinaceae), native to the Central European Alps and the Carpathian Mountains, are not well known. The aim of the present work was to examine the phenolic content, antioxidant and antimicrobial effects of hydromethanolic
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The chemical constituents and biological activity of Pinus cembra L. (Pinaceae), native to the Central European Alps and the Carpathian Mountains, are not well known. The aim of the present work was to examine the phenolic content, antioxidant and antimicrobial effects of hydromethanolic extracts of Pinus cembra L. bark and needles. Bark extract had higher concentrations of total phenolics (299.3 vs. 78.22 mg gallic acid equivalents/g extract), flavonoids (125.3 vs. 19.84 mg catechin equivalents/g extract) and proanthocyanidins (74.3 vs. 12.7 mg cyanidin equivalents/g extract) than needle extract and was more active as a free radical scavenger, reducing agent and antimicrobial agent. The EC50 values in the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) and reducing power assays were 71.1, 6.3 and 26 mg/mL for bark extract and 186.1, 24 and 104 mg/mL for needle extract, respectively. In addition, needle extract showed ferrous ions chelating effects (EC50 = 1,755 μg/mL). The antimicrobial effects against Staphylococcus aureus, Sarcina lutea, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans were assessed by the agar diffusion method. Both extracts (4 mg/well) were active against all the microorganisms tested; bark extract showed higher inhibition on all strains. These results indicate that Pinus cembra L. bark and needles are good sources of phytochemicals with antioxidant and antimicrobial activities. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Synthesis, Characterization and Fluorescent Property Evaluation of 1,3,5-Triaryl-2-pyrazolines
Molecules 2011, 16(9), 7789-7802; doi:10.3390/molecules16097789
Received: 12 July 2011 / Revised: 3 August 2011 / Accepted: 10 August 2011 / Published: 13 September 2011
Cited by 24 | PDF Full-text (666 KB)
Abstract
A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the
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A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the reaction mixture onto crushed ice. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The 1,3,5-triaryl-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible spectrum when irradiated with ultraviolet radiation. The fluorescent behavior of these compounds was studied by UV-Vis and emission spectroscopy, performed at room temperature. Full article
Open AccessArticle Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine, a Novel Camptothecin Analogue, Induces Apoptosis towards Hepatocellular Carcinoma SMMC-7721 Cells
Molecules 2011, 16(9), 7803-7814; doi:10.3390/molecules16097803
Received: 28 July 2011 / Revised: 25 August 2011 / Accepted: 6 September 2011 / Published: 13 September 2011
Cited by 8 | PDF Full-text (2229 KB)
Abstract
Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine (B2) is a novel camptothecin analogue. Our previous study had shown that it displayed higher cytoxicity activity towards hepatocellular carcinoma SMMC-7721 cells than camptothecin (CPT) in vitro. In this paper, the underlying mechanism of anti-proliferation of B2
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Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine (B2) is a novel camptothecin analogue. Our previous study had shown that it displayed higher cytoxicity activity towards hepatocellular carcinoma SMMC-7721 cells than camptothecin (CPT) in vitro. In this paper, the underlying mechanism of anti-proliferation of B2 towards SMMC-7721 cells was further examined. Cell growth inhibition of B2 was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; morphological changes were observed under Laser Scanning Confocal Microscope (LSCM); cell cycle distribution, apoptotic population, changes in mitochondrial membrane potential, intracellular calcium concentration and reactive oxygen species (ROS) production were determined by flow cytometry (FCM). Activities of caspase-3 and caspase-9 were measured, and the expression level of Bcl-2 and Bax proteins were analyzed by Western blot. The results suggested that B2 inhibited SMMC-7721 cell growth by causing cell cycle arrest at the S and G2/M phases, and induced apoptosis involving a mitochondrial pathway. B2 appears to cause a high induction of apoptosis on SMMC-7721 cells in vitro, which suggests it might be a potential drug for cancer therapy. Full article
Open AccessArticle Schiff Bases of Indoline-2,3-dione: Potential Novel Inhibitors of Mycobacterium Tuberculosis (Mtb) DNA Gyrase
Molecules 2011, 16(9), 7864-7879; doi:10.3390/molecules16097864
Received: 27 July 2011 / Revised: 23 August 2011 / Accepted: 7 September 2011 / Published: 13 September 2011
Cited by 21 | PDF Full-text (778 KB)
Abstract
In the present study a series of Schiff bases of indoline-2,3-dione were synthesized and investigated for their Mtb gyrase inhibitory activity. Promising inhibitory activity was demonstrated with some of these derivatives, which exhibited IC50 values ranging from 50–157 mM. The orientation and
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In the present study a series of Schiff bases of indoline-2,3-dione were synthesized and investigated for their Mtb gyrase inhibitory activity. Promising inhibitory activity was demonstrated with some of these derivatives, which exhibited IC50 values ranging from 50–157 mM. The orientation and the ligand-receptor interactions of such molecules within the Mtb DNA gyrase A subunit active site were investigated applying a multi-step docking protocol using Molecular Operating Environment (MOE) and Autodock4 docking software. The results revealed the importance of the isatin moiety and the connecting side chain for strong interactions with the enzyme active site. Among the tested compounds the terminal aromatic ring benzofuran showed the best activity. Promising new leads for developing a novel class of Mtb gyrase inhibitors were obtained from Schiff bases of indoline-2,3-dione. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessArticle Formulation and Evaluation of Celastrol-Loaded Liposomes
Molecules 2011, 16(9), 7880-7892; doi:10.3390/molecules16097880
Received: 21 July 2011 / Revised: 5 September 2011 / Accepted: 5 September 2011 / Published: 13 September 2011
Cited by 18 | PDF Full-text (586 KB)
Abstract
The main purpose of this study was to evaluate the intestinal absorption and the antineoplastic effect of the poorly water-soluble drug celastrol when liposomes were used as oral drug delivery system. Liposomes were prepared by the ethanol-injection method. An optimized liposome formulation composed
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The main purpose of this study was to evaluate the intestinal absorption and the antineoplastic effect of the poorly water-soluble drug celastrol when liposomes were used as oral drug delivery system. Liposomes were prepared by the ethanol-injection method. An optimized liposome formulation composed of phospholipid, cholesterol and Tween-80 resulted in favorable encapsulation efficiency at 98.06 ± 0.94%. Homogeneous and stable particle size of 89.6 ± 7.3 nm and zeta potential of −(87.7 ± 5.8) mV were determined by laser particle size analyzer. Subsequently, the four-site perfusion rat intestinal model revealed that celastrol-loaded liposomes had improved effective permeability compared to the free drug in four intestinal segments (p < 0.05). Moreover, celastrol-loaded liposomes could also inhibit the tumor growth in C57BL/6 mice. These results suggest that liposomes could be a promising perioral carrier for celastrol. Full article
Open AccessArticle Studies on Log Po/w of Quinoxaline di-N-Oxides: A Comparison of RP-HPLC Experimental and Predictive Approaches
Molecules 2011, 16(9), 7893-7908; doi:10.3390/molecules16097893
Received: 30 August 2011 / Revised: 6 September 2011 / Accepted: 7 September 2011 / Published: 13 September 2011
Cited by 4 | PDF Full-text (414 KB) | Supplementary Files
Abstract
As reported in our previous papers, a series of quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and studied as anti-tuberculosis agents. Here, the capability of the shake-flask method was studied and the retention time (expressed as log K) of 20 compounds were
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As reported in our previous papers, a series of quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and studied as anti-tuberculosis agents. Here, the capability of the shake-flask method was studied and the retention time (expressed as log K) of 20 compounds were determined by RP-HPLC analysis. We found that the prediction of log P by the RP-HPLC analysis can result in a high accuracy and can replace the shake-flask method avoiding the experimental problems presented by quinoxaline di-N-oxides. The studied compounds were subjected to the ALOGPS module with the aim of comparing experimental log Po/w values and predicted data. Moreover, a preliminary in silico screening of the QSAR relationship was made confirming the influence of reduction peak potential, lipophilicity, H-bond donor capacity and molecular dimension descriptors on anti-tuberculosis activity. Full article
Open AccessArticle Chemical Profile of the Organic Residue from Ancient Amphora Found in the Adriatic Sea Determined by Direct GC and GC-MS Analysis
Molecules 2011, 16(9), 7936-7948; doi:10.3390/molecules16097936
Received: 18 August 2011 / Revised: 7 September 2011 / Accepted: 7 September 2011 / Published: 14 September 2011
Cited by 7 | PDF Full-text (577 KB)
Abstract
An ancient organic residue was collected from the bottom of a Greco-Italian amphora found in the Adriatic Sea and investigated by direct GC and GC-MS analysis. The headspace composition was determined by HS-SPME using: (1) DVB/CAR/PDMS and (2) PDMS/DVB fibres. Higher percentages of
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An ancient organic residue was collected from the bottom of a Greco-Italian amphora found in the Adriatic Sea and investigated by direct GC and GC-MS analysis. The headspace composition was determined by HS-SPME using: (1) DVB/CAR/PDMS and (2) PDMS/DVB fibres. Higher percentages of benzene derivatives, monoterpenes and other low-molecular aliphatic compounds were obtained by method (1) in contrast to higher percentage of naphthalene and phenanthrene derivatives found by method (2). In comparison with the composition of pine resin, it is more likely that the found low-molecular aliphatic alcohols, acids, esters and carbonyls with 2-phenylethanol were trapped and preserved within the organic residue from stored wine – the amphora’s originally content. Semi-volatile diterpenes methyl dehydroabietate (33.6%) and retene (24.1%) were dominant in the residue CH2Cl2 solution. Other abundant compounds were 1,4-dimethoxyphenanthrene (6.8%) as well as other naphthalene and/or phenanthrene derivatives [7-(1-methylethyl)-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydronaphthalene, 7-(1-methylethyl)-1,4a-dimethyl-2,3,4,4a,9,10-hexahydrophenanthrene, 7-(1-methylethyl)-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydro-phenanthrene, 3,6-dimethylphenanthrene and 2,3,5-trimethylphenanthrene]. Possible sources and formation pathways of the major compounds in the residue were discussed. Full article
Open AccessArticle Isolation and Purification of Oridonin from the Whole Plant of Isodon rubescens by High-Speed Counter-Current Chromatography
Molecules 2011, 16(9), 7949-7957; doi:10.3390/molecules16097949
Received: 18 July 2011 / Revised: 24 August 2011 / Accepted: 25 August 2011 / Published: 14 September 2011
Cited by 5 | PDF Full-text (645 KB)
Abstract
Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v). The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance
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Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v). The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance liquid chromatography (HPLC). A total of 40.6 mg of oridonin with the purity of 73.5% was obtained in less than 100 min from 100 mg of crude Isodon rubescens extract. The chemical structure of the compound was identified by IR, 1H-NMR and 13C-NMR. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Allicin Reduces the Production of α-Toxin by Staphylococcus aureus
Molecules 2011, 16(9), 7958-7968; doi:10.3390/molecules16097958
Received: 20 July 2011 / Revised: 1 September 2011 / Accepted: 7 September 2011 / Published: 15 September 2011
Cited by 12 | PDF Full-text (482 KB)
Abstract
Staphylococcus aureus causes a broad range of life-threatening diseases in humans. The pathogenicity of this micro-organism is largely dependent upon its virulence factors. One of the most extensively studied virulence factors is the extracellular protein α-toxin. In this study, we show that allicin,
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Staphylococcus aureus causes a broad range of life-threatening diseases in humans. The pathogenicity of this micro-organism is largely dependent upon its virulence factors. One of the most extensively studied virulence factors is the extracellular protein α-toxin. In this study, we show that allicin, an organosulfur compound, was active against S. aureus with MICs ranged from 32 to 64 μg/mL. Haemolysis, Western blot and real-time RT-PCR assays were used to evaluate the effects of allicin on S. aureus α-toxin production and on the levels of gene expression, respectively. The results of our study indicated that sub-inhibitory concentrations of allicin decreased the production of α-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in a dose-dependent manner. Furthermore, the transcriptional levels of agr (accessory gene regulator) in S. aureus were inhibited by allicin. Therefore, allicin may be useful in the treatment of α-toxin-producing S. aureus infections. Full article
Open AccessCommunication Synthesis and NMR-Study of the 2,3,4,5-Tetraethylsilole Dianion [SiC4Et4]2−•2[Li]+
Molecules 2011, 16(9), 8033-8040; doi:10.3390/molecules16098033
Received: 31 August 2011 / Revised: 8 September 2011 / Accepted: 14 September 2011 / Published: 16 September 2011
Cited by 4 | PDF Full-text (419 KB)
Abstract
The previously unknown silole dianion [SiC4Et4]2−•2[Li]+ (3) was prepared by the sonication of 1,1-dichloro-2,3,4,5-tetraethyl-1-silacyclopentadiene [Cl2SiC4Et4, 2] with more than four equivalent of lithium in THF. 1H-,
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The previously unknown silole dianion [SiC4Et4]2−•2[Li]+ (3) was prepared by the sonication of 1,1-dichloro-2,3,4,5-tetraethyl-1-silacyclopentadiene [Cl2SiC4Et4, 2] with more than four equivalent of lithium in THF. 1H-, 13C-, and 29Si-NMR data of 3 are compared with those of the reported silole dianion [SiC4Ph4]2−. Trapping of 3 with trimethylchlorosilane gave 1,1-bis(trimethylsilyl)-2,3,4,5-tetraethyl-1-silacyclopentadiene [(Me3Si)2SiC4Et4, 4] in high yield. The silole of 2 was synthesized in high yield in three steps by a modified procedure using Cp2ZrCl2 via Cp2ZrC4Et4 and 1,4-dibromo-1,2,3,4-tetraethyl-1,3-butadiene. Full article
(This article belongs to the Special Issue Organosilicon Chemistry)
Open AccessCommunication Intramolecular C-H···O Hydrogen Bonding in 1,4-Dihydropyridine Derivatives
Molecules 2011, 16(9), 8041-8052; doi:10.3390/molecules16098041
Received: 26 July 2011 / Revised: 8 September 2011 / Accepted: 9 September 2011 / Published: 19 September 2011
Cited by 11 | PDF Full-text (562 KB) | Supplementary Files
Abstract
The diastereotopy of the methylene protons at positions 2 and 6 in 1,4-dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH···O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences
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The diastereotopy of the methylene protons at positions 2 and 6 in 1,4-dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH···O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences in the 1H-NMR spectra. Full article
Open AccessArticle A Short Synthesis of Bisabolane Sesquiterpenes
Molecules 2011, 16(9), 8053-8061; doi:10.3390/molecules16098053
Received: 31 August 2011 / Revised: 4 September 2011 / Accepted: 14 September 2011 / Published: 19 September 2011
Cited by 6 | PDF Full-text (436 KB)
Abstract
A facile total synthesis of three members of the bisabolane sesquiterpene family, namely (±)-curcumene, (±)-xanthorrhizol and (±)-curcuhydroquinone had been achieved in high overall yield. The synthesis used bromobenzene derivatives as starting materials. The halogen-lithium exchange followed by addition of isoprenylacetone and reduction of
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A facile total synthesis of three members of the bisabolane sesquiterpene family, namely (±)-curcumene, (±)-xanthorrhizol and (±)-curcuhydroquinone had been achieved in high overall yield. The synthesis used bromobenzene derivatives as starting materials. The halogen-lithium exchange followed by addition of isoprenylacetone and reduction of the obtained carbinols are the key steps of the synthetic pathway. This synthetic approach provides a new route to the bisabolane sesquiterpenes. Full article
(This article belongs to the Special Issue Terpenoids)
Open AccessArticle Effects of St John's Wort (Hypericum perforatum L.) Extracts on Epileptogenesis
Molecules 2011, 16(9), 8062-8075; doi:10.3390/molecules16098062
Received: 22 August 2011 / Revised: 13 September 2011 / Accepted: 15 September 2011 / Published: 19 September 2011
Cited by 4 | PDF Full-text (439 KB) | Supplementary Files
Abstract
The purpose of this study was to investigate the effects of treatment with water, n-butanol and ether extracts of Hypercom perforatum L. on epileptogenesis in rabbits. Animals from the control group received solvent-ethanol, and the kindling model of epilepsy was used.
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The purpose of this study was to investigate the effects of treatment with water, n-butanol and ether extracts of Hypercom perforatum L. on epileptogenesis in rabbits. Animals from the control group received solvent-ethanol, and the kindling model of epilepsy was used. Epileptic focus was induced in Chinchilla rabbits by stimulation of the hippocampus. The following parameters were determined: the minimum current strength necessary to induce after-discharge (AD) – discharges appearing after cessation of stimulation; AD duration; the number of stimulations necessary to induce spontaneous kindling; and the latency time for the development of full kindling. The results obtained indicate that epileptogenesis is influenced by Hypericum perforatum L. extract treatment. Animals treated with an ether extract of Hypericum perforatum L. required significantly weaker minimum current strengths for the development of epileptogenic focus, and displayed longer AD times, while the number of electro-stimulations necessary for full kindling was less. In contrast, animals treated with water and n-butanol extracts required increased electro-stimulations for the development of epileptic discharge, and displayed shortened AD durations versus controls. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessCommunication Two New Triterpenoids from Lysimachia heterogenea Klatt and Evaluation of Their Cytotoxicity
Molecules 2011, 16(9), 8076-8082; doi:10.3390/molecules16098076
Received: 15 August 2011 / Revised: 7 September 2011 / Accepted: 8 September 2011 / Published: 20 September 2011
Cited by 6 | PDF Full-text (372 KB)
Abstract
Two new 13,28-epoxy oleanane-type triterpenoids, namely heterogenoside E and F, were isolated from Lysimachia heterogenea Klatt, together with the eight known compounds: palmitic acid, β-stigmasterol, kaempferol, quercetin, hyperin, isorhamnetin, isorhamnetin-3-O-galactopyranoside and anagallisin C. Heterogenoside F possesses acetoxyl groups at the
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Two new 13,28-epoxy oleanane-type triterpenoids, namely heterogenoside E and F, were isolated from Lysimachia heterogenea Klatt, together with the eight known compounds: palmitic acid, β-stigmasterol, kaempferol, quercetin, hyperin, isorhamnetin, isorhamnetin-3-O-galactopyranoside and anagallisin C. Heterogenoside F possesses acetoxyl groups at the unusual C-21 and C-22 positions of its oleanane skeleton. The cytotoxic activities of anagallisin C, heterogenoside E and F were weak. Full article
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Open AccessArticle Design and Synthesis of New N-(5-Trifluoromethyl)-1H-1,2,4-triazol-3-yl Benzenesulfonamides as Possible Antimalarial Prototypes
Molecules 2011, 16(9), 8083-8097; doi:10.3390/molecules16098083
Received: 1 August 2011 / Revised: 9 September 2011 / Accepted: 16 September 2011 / Published: 20 September 2011
Cited by 10 | PDF Full-text (706 KB)
Abstract
A rational approach was used to synthesize a new set of 15 1H-1,2,4-triazol-3-yl benzenesulfonamide derivatives with the aim of developing new antimalarial lead compounds. These derivatives were prepared in yields between 50% and 62%, and their structures were elucidated using IR,
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A rational approach was used to synthesize a new set of 15 1H-1,2,4-triazol-3-yl benzenesulfonamide derivatives with the aim of developing new antimalarial lead compounds. These derivatives were prepared in yields between 50% and 62%, and their structures were elucidated using IR, 1H-, 13C-, 19F-NMR, MS and elemental analysis. A docking study based on sulfonamides previously used against malaria identified trifluoromethyl-substituted derivatives to be the best lead compounds for new antimalarial drug development. Full article
(This article belongs to the Special Issue Fluorine Chemistry 2016)
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Open AccessArticle Enzymatic Kinetic Resolution of tert-Butyl 2-(1-Hydroxyethyl)phenylcarbamate, A Key Intermediate to Chiral Organoselenanes and Organotelluranes
Molecules 2011, 16(9), 8098-8109; doi:10.3390/molecules16098098
Received: 19 August 2011 / Revised: 14 September 2011 / Accepted: 15 September 2011 / Published: 20 September 2011
Cited by 2 | PDF Full-text (552 KB)
Abstract
The enzymatic kinetic resolution of tert-butyl 2-(1-hydroxyethyl) phenylcarbamate via lipase-catalyzed transesterification reaction was studied. We investigated several reaction conditions and the carbamate was resolved by Candida antarctica lipase B (CAL-B), leading to the optically pure (R)- and (S)-enantiomers. The
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The enzymatic kinetic resolution of tert-butyl 2-(1-hydroxyethyl) phenylcarbamate via lipase-catalyzed transesterification reaction was studied. We investigated several reaction conditions and the carbamate was resolved by Candida antarctica lipase B (CAL-B), leading to the optically pure (R)- and (S)-enantiomers. The enzymatic process showed excellent enantioselectivity (E > 200). (R)- and (S)-tert-butyl 2-(1-hydroxyethyl)phenylcarbamate were easily transformed into the corresponding (R)- and (S)-1-(2-aminophenyl)ethanols. Full article
(This article belongs to the Special Issue Enzyme-Catalyzed Reactions)
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Open AccessArticle Solid-Phase Synthesis of a New Diphosphate 5-Aminoimidazole-4-carboxamide Riboside (AICAR) Derivative and Studies toward Cyclic AICAR Diphosphate Ribose
Molecules 2011, 16(9), 8110-8118; doi:10.3390/molecules16098110
Received: 1 August 2011 / Revised: 9 September 2011 / Accepted: 13 September 2011 / Published: 21 September 2011
Cited by 8 | PDF Full-text (444 KB)
Abstract
The solid-phase synthesis of the first example of a new diphosphate AICAR derivative is reported. The new substance is characterized by the presence of a 5'-phosphate group while a second phosphate moiety is installed on a 5-hydroxypentyl chain attached to the 4-N
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The solid-phase synthesis of the first example of a new diphosphate AICAR derivative is reported. The new substance is characterized by the presence of a 5'-phosphate group while a second phosphate moiety is installed on a 5-hydroxypentyl chain attached to the 4-N-position of AICAR. Cyclization of the diphosphate derivative by pyrophosphate bond formation allowed for the formation of a novel AICAR-based cyclic ADP-ribose (cADPR) mimic. Full article
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Open AccessArticle Antiphytoviral Activity of Sesquiterpene-Rich Essential Oils from Four Croatian Teucrium Species
Molecules 2011, 16(9), 8119-8129; doi:10.3390/molecules16098119
Received: 25 July 2011 / Revised: 12 September 2011 / Accepted: 14 September 2011 / Published: 21 September 2011
Cited by 13 | PDF Full-text (392 KB)
Abstract
The purpose of this study was to compare the essential oil profiles of four Croatian Teucrium species (Lamiaceae), as determined by GC and GC/MS, with their antiphytoviral efficiency. A phytochemical analysis showed that T. polium, T. flavum, T. montanum and T.
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The purpose of this study was to compare the essential oil profiles of four Croatian Teucrium species (Lamiaceae), as determined by GC and GC/MS, with their antiphytoviral efficiency. A phytochemical analysis showed that T. polium, T. flavum, T. montanum and T. chamaedrys are characterized by similar essential oil compositions. The investigated oils are characterized by a high proportion of the sesquiterpene hydrocarbons β-caryophyllene (7.1–52.0%) and germacrene D (8.7–17.0%). Other important components were β-pinene from T. montanum and α-pinene from T. flavum. The investigated essential oils were proved to reduce lesion number in the local host Chenopodium quinoa Willd. infected with Cucumber Mosaic Virus (CMV), with reductions of 41.4%, 22.9%, 44.3% and 25.7%, respectively. Full article
(This article belongs to the Special Issue Terpenoids)
Open AccessArticle Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media
Molecules 2011, 16(9), 8130-8142; doi:10.3390/molecules16098130
Received: 28 June 2011 / Revised: 26 August 2011 / Accepted: 26 August 2011 / Published: 22 September 2011
Cited by 13 | PDF Full-text (515 KB)
Abstract
The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in
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The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (Dc and Dc) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents. Full article

Review

Jump to: Research

Open AccessReview Recent Advances in Microflow Photochemistry
Molecules 2011, 16(9), 7522-7550; doi:10.3390/molecules16097522
Received: 12 August 2011 / Revised: 31 August 2011 / Accepted: 31 August 2011 / Published: 5 September 2011
Cited by 96 | PDF Full-text (736 KB)
Abstract
This review summarizes recent advances in microflow photochemical technologies and transformations. The portfolio of reactions comprises homogeneous and heterogeneous types, among them photoadditions, photorearrangements, photoreductions, photodecarboxylations, photooxygenations and photochlorinations. While microflow photochemistry is most commonly employed as a micro-scale synthesis tool, scale-up and
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This review summarizes recent advances in microflow photochemical technologies and transformations. The portfolio of reactions comprises homogeneous and heterogeneous types, among them photoadditions, photorearrangements, photoreductions, photodecarboxylations, photooxygenations and photochlorinations. While microflow photochemistry is most commonly employed as a micro-scale synthesis tool, scale-up and technical production processes have already been developed. Full article
(This article belongs to the Special Issue Flow Chemistry)
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Open AccessReview Gold-Catalyzed Cyclizations of Alkynol-Based Compounds: Synthesis of Natural Products and Derivatives
Molecules 2011, 16(9), 7815-7843; doi:10.3390/molecules16097815
Received: 15 August 2011 / Revised: 5 September 2011 / Accepted: 8 September 2011 / Published: 13 September 2011
Cited by 37 | PDF Full-text (649 KB)
Abstract
The last decade has witnessed dramatic growth in the number of reactions catalyzed by gold complexes because of their powerful soft Lewis acid nature. In particular, the gold-catalyzed activation of propargylic compounds has progressively emerged in recent years. Some of these gold-catalyzed reactions
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The last decade has witnessed dramatic growth in the number of reactions catalyzed by gold complexes because of their powerful soft Lewis acid nature. In particular, the gold-catalyzed activation of propargylic compounds has progressively emerged in recent years. Some of these gold-catalyzed reactions in alkynes have been optimized and show significant utility in organic synthesis. Thus, apart from significant methodology work, in the meantime gold-catalyzed cyclizations in alkynol derivatives have become an efficient tool in total synthesis. However, there is a lack of specific review articles covering the joined importance of both gold salts and alkynol-based compounds for the synthesis of natural products and derivatives. The aim of this Review is to survey the chemistry of alkynol derivatives under gold-catalyzed cyclization conditions and its utility in total synthesis, concentrating on the advances that have been made in the last decade, and in particular in the last quinquennium. Full article
(This article belongs to the Special Issue Gold Catalysts)
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Open AccessReview One Step Formation of Propene from Ethene or Ethanol through Metathesis on Nickel Ion-loaded Silica
Molecules 2011, 16(9), 7844-7863; doi:10.3390/molecules16097844
Received: 30 June 2011 / Revised: 4 August 2011 / Accepted: 5 September 2011 / Published: 13 September 2011
Cited by 25 | PDF Full-text (1975 KB)
Abstract
Increased propene production is presently one of the most significant objectives in petroleum chemistry. Especially the one-step conversion of ethene to propene (ETP reaction, 3C2H4 ® 2C3H6) is the most desired process. In our efforts, nickel
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Increased propene production is presently one of the most significant objectives in petroleum chemistry. Especially the one-step conversion of ethene to propene (ETP reaction, 3C2H4 ® 2C3H6) is the most desired process. In our efforts, nickel ion-loaded mesoporous silica could turn a new type of ETP reaction into reality. The one-step conversion of ethene was 68% and the propene selectivity was 48% in a continuous gas-flow system at 673 K and atmospheric pressure. The reactivity of lower olefins and the dependences of the ETP reaction on the contact time and the partial pressure of ethene were consistent with a reaction mechanism involving dimerization of ethene to 1-butene, isomerization of 1-butene to 2-butene, and metathesis of 2-butene and ethene to yield propene. The reaction was then expanded to an ethanol-to-propene reaction on the same catalyst, in which two possible reaction routes are suggested to form ethene from ethanol. The catalysts were characterized mainly by EXAFS and TPR techniques. The local structures of the nickel species active for the ETP reaction were very similar to that of layered nickel silicate, while those on the inert catalysts were the same as that of NiO particles.  Full article
(This article belongs to the Special Issue Olefin Metathesis and Its Application)
Open AccessReview Pyrene: A Probe to Study Protein Conformation and Conformational Changes
Molecules 2011, 16(9), 7909-7935; doi:10.3390/molecules16097909
Received: 1 August 2011 / Revised: 4 September 2011 / Accepted: 6 September 2011 / Published: 14 September 2011
Cited by 75 | PDF Full-text (2960 KB)
Abstract
The review focuses on the unique spectral features of pyrene that can be utilized to investigate protein structure and conformation. Pyrene is a fluorescent probe that can be attached covalently to protein side chains, such as sulfhydryl groups. The spectral features of pyrene
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The review focuses on the unique spectral features of pyrene that can be utilized to investigate protein structure and conformation. Pyrene is a fluorescent probe that can be attached covalently to protein side chains, such as sulfhydryl groups. The spectral features of pyrene are exquisitely sensitive to the microenvironment of the probe: it exhibits an ensemble of monomer fluorescence emission peaks that report on the polarity of the probe microenvironment, and an additional band at longer wavelengths, the appearance of which reflects the presence of another pyrene molecule in spatial proximity (~10 Å). Its high extinction coefficient allows us to study labeled proteins in solution at physiologically relevant concentrations. The environmentally- and spatially-sensitive features of pyrene allow monitoring protein conformation, conformational changes, protein folding and unfolding, protein-protein, protein-lipid and protein-membrane interactions. Full article
Open AccessReview Modulation of Animal and Human Hematopoiesis by β-Glucans: A Review
Molecules 2011, 16(9), 7969-7979; doi:10.3390/molecules16097969
Received: 15 August 2011 / Revised: 5 September 2011 / Accepted: 9 September 2011 / Published: 15 September 2011
Cited by 8 | PDF Full-text (377 KB)
Abstract
β-Glucans are cell wall constituents of bacteria, yeast, fungi, and plants. They are not expressed in mammalian cells, but they are recognized by mammalian cells as pathogen-associated molecular patterns by pattern recognition receptors and thus act as biological response modifiers. This review summarizes
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β-Glucans are cell wall constituents of bacteria, yeast, fungi, and plants. They are not expressed in mammalian cells, but they are recognized by mammalian cells as pathogen-associated molecular patterns by pattern recognition receptors and thus act as biological response modifiers. This review summarizes data on the hematopoiesis-stimulating effects of β-glucans, as well as on their ability to enhance bone marrow recovery after an injury. β-Glucans have been shown to support murine hematopoiesis suppressed by ionizing radiation or cytotoxic anti-cancer therapy. They also enhance stem cell homing and engraftment. Basically, two forms of β-glucan preparations have been investigated, namely particulate and soluble ones. β-Glucans are generally well tolerated, the particulate forms showing a higher incidence of undesirable side effects. Taken together, the hematopoiesis-stimulating properties of β-glucans predetermine these biological response modifiers to ever increasing use in human medicinal practice. Full article
(This article belongs to the Special Issue Natural Polysaccharides: Chemistry, Bioactivity and Analysis)
Open AccessReview Thymidine Analogues for Tracking DNA Synthesis
Molecules 2011, 16(9), 7980-7993; doi:10.3390/molecules16097980
Received: 31 August 2011 / Accepted: 8 September 2011 / Published: 15 September 2011
Cited by 43 | PDF Full-text (679 KB)
Abstract
Replicating cells undergo DNA synthesis in the highly regulated, S-phase of the cell cycle. Analogues of the pyrimidine deoxynucleoside thymidine may be inserted into replicating DNA, effectively tagging dividing cells allowing their characterisation. Tritiated thymidine, targeted using autoradiography was technically demanding and superseded
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Replicating cells undergo DNA synthesis in the highly regulated, S-phase of the cell cycle. Analogues of the pyrimidine deoxynucleoside thymidine may be inserted into replicating DNA, effectively tagging dividing cells allowing their characterisation. Tritiated thymidine, targeted using autoradiography was technically demanding and superseded by 5-bromo-2-deoxyuridine (BrdU) and related halogenated analogues, detected using antibodies. Their detection required the denaturation of DNA, often constraining the outcome of investigations. Despite these limitations BrdU alone has been used to target newly synthesised DNA in over 20,000 reviewed biomedical studies. A recent breakthrough in “tagging DNA synthesis” is the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU). The alkyne group in EdU is readily detected using a fluorescent azide probe and copper catalysis using ‘Huisgen’s reaction’ (1,3-dipolar cycloaddition or ‘click chemistry’). This rapid, two-step biolabelling approach allows the tagging and imaging of DNA within cells whilst preserving the structural and molecular integrity of the cells. The bio-orthogonal detection of EdU allows its application in more experimental assays than previously possible with other “unnatural bases”. These include physiological, anatomical and molecular biological experimentation in multiple fields including, stem cell research, cancer biology, and parasitology. The full potential of EdU and related molecules in biomedical research remains to be explored. Full article
(This article belongs to the Special Issue Nucleoside Analogues)
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Open AccessReview Exploiting the Nucleotide Substrate Specificity of Repair DNA Polymerases To Develop Novel Anticancer Agents
Molecules 2011, 16(9), 7994-8019; doi:10.3390/molecules16097994
Received: 5 July 2011 / Revised: 26 August 2011 / Accepted: 13 September 2011 / Published: 16 September 2011
Cited by 3 | PDF Full-text (522 KB)
Abstract
The genome is constantly exposed to mutations that can originate during replication or as a result of the action of both endogenous and/or exogenous damaging agents [such as reactive oxygen species (ROS), UV light, genotoxic environmental compounds, etc.]. Cells have developed a
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The genome is constantly exposed to mutations that can originate during replication or as a result of the action of both endogenous and/or exogenous damaging agents [such as reactive oxygen species (ROS), UV light, genotoxic environmental compounds, etc.]. Cells have developed a set of specialized mechanisms to counteract this mutational burden. Many cancer cells have defects in one or more DNA repair pathways, hence they rely on a narrower set of specialized DNA repair mechanisms than normal cells. Inhibiting one of these pathways in the context of an already DNA repair-deficient genetic background, will be more toxic to cancer cells than to normal cells, a concept recently exploited in cancer chemotherapy by the synthetic lethality approach. Essential to all DNA repair pathways are the DNA pols. Thus, these enzymes are being regarded as attractive targets for the development of specific inhibitors of DNA repair in cancer cells. In this review we examine the current state-of-the-art in the development of nucleotide analogs as inhibitors of repair DNA polymerases. Full article
(This article belongs to the Special Issue Nucleoside Analogues)
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Open AccessReview The Potential of Tetrandrine as a Protective Agent for Ischemic Stroke
Molecules 2011, 16(9), 8020-8032; doi:10.3390/molecules16098020
Received: 25 August 2011 / Revised: 15 September 2011 / Accepted: 15 September 2011 / Published: 16 September 2011
Cited by 10 | PDF Full-text (368 KB)
Abstract
Stroke is one of the leading causes of mortality, with a high incidence of severe morbidity in survivors. The treatment to minimize tissue injury after stroke is still unsatisfactory and it is mandatory to develop effective treatment strategies for stroke. The pathophysiology of
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Stroke is one of the leading causes of mortality, with a high incidence of severe morbidity in survivors. The treatment to minimize tissue injury after stroke is still unsatisfactory and it is mandatory to develop effective treatment strategies for stroke. The pathophysiology of ischemic stroke is complex and involves many processes including energy failure, loss of ion homeostasis, increased intracellular calcium level, platelet aggregation, production of reactive oxygen species, disruption of blood brain barrier, and inflammation and leukocyte infiltration, etc. Tetrandrine, a bisbenzylisoquinoline alkaloid, has many pharmacologic effects including anti-inflammatory and cytoprotective effects. In addition, tetrandrine has been found to protect the liver, heart, small bowel and brain from ischemia/reperfusion injury. It is a calcium channel blocker, and can inhibit lipid peroxidation, reduce generation of reactive oxygen species, suppress the production of cytokines and inflammatory mediators, inhibit neutrophil recruitment and platelet aggregation, which are all devastating factors during ischemia/reperfusion injury of the brain. Because tetrandrine can counteract these important pathophysiological processes of ischemic stroke, it has the potential to be a protective agent for ischemic stroke. Full article
(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)

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