Molecules

1764 KiB

Open AccessArticle

Carapanolides T–X from Carapa guianensis (Andiroba) Seeds

by Teppei Miyake, Sari Ishimoto, Naoko Ishimatsu, Keiichiro Higuchi, Katsuhiko Minoura, Takashi Kikuchi, Takeshi Yamada, Osamu Muraoka and Reiko Tanaka

Molecules 2015, 20(11), 20955-20966; https://doi.org/10.3390/molecules201119737 - 24 Nov 2015

Cited by 21 | Viewed by 5204

Abstract

Two new mexicanolide-type limonoids, carapanolides T–U (1–2), and three new phragmalin-type limonoids, carapanolides V–X (3–5), were isolated from the seeds of Carapa guianensis (andiroba). Their structures were determined on the basis of 1D- and 2D-NMR spectroscopy. Full article

(This article belongs to the Section Natural Products Chemistry)

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2184 KiB

Open AccessArticle

Clones of FeSOD, MDHAR, DHAR Genes from White Clover and Gene Expression Analysis of ROS-Scavenging Enzymes during Abiotic Stress and Hormone Treatments

by Yan Zhang, Zhou Li, Yan Peng, Xiaojuan Wang, Dandan Peng, Yaping Li, Xiaoshuang He, Xinquan Zhang, Xiao Ma, Linkai Huang and Yanhong Yan

Molecules 2015, 20(11), 20939-20954; https://doi.org/10.3390/molecules201119741 - 24 Nov 2015

Cited by 56 | Viewed by 7874 | Correction

Abstract

Increased transcriptional levels of genes encoding antioxidant enzymes play important protective roles in coping with excessive accumulation of reactive oxygen species (ROS) in plants exposed to various abiotic stresses. To fully elucidate different evolutions and functions of ROS-scavenging enzymatic genes, we isolated iron [...] Read more.

Increased transcriptional levels of genes encoding antioxidant enzymes play important protective roles in coping with excessive accumulation of reactive oxygen species (ROS) in plants exposed to various abiotic stresses. To fully elucidate different evolutions and functions of ROS-scavenging enzymatic genes, we isolated iron superoxide dismutase (FeSOD), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) from white clover for the first time and subsequently tested dynamic expression profiles of these genes together with previously identified other antioxidant enzyme genes including copper zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD), glutathione reductase (GR), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in response to cold, drought, salinity, cadmium stress and exogenous abscisic acid (ABA) or spermidine (Spd) treatment. The cloned fragments of FeSOD, DHAR and MDHAR genes were 630, 471 and 669 bp nucleotide sequences encoding 210, 157 and 223 amino acids, respectively. Phylogenetic analysis indicated that both amino acid and nucleotide sequences of these three genes are highly conservative. In addition, the analysis of genes expression showed the transcription of GR, POD, MDHAR, DHAR and Cu/ZnSOD were rapidly activated with relatively high abundance during cold stress. Differently, CAT, APX, FeSOD, Cu/ZnSOD and MnSOD exhibited more abundant transcripts compared to others under drought stress. Under salt stress, CAT was induced preferentially (3–12 h) compared to GR which was induced later (12–72 h). Cadmium stress mainly up-regulated Cu/ZnSOD, DHAR and MDHAR. Interestingly, most of genes expression induced by ABA or Spd happened prior to various abiotic stresses. The particular expression patterns and different response time of these genes indicated that white clover differentially activates genes encoding antioxidant enzymes to mitigate the damage of ROS during various environmental stresses. Full article

(This article belongs to the Section Bioorganic Chemistry)

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3273 KiB

Open AccessCommunication

Synthesis, Crystal Structure, Absolute Configuration and Antitumor Activity of the Enantiomers of 5-Bromo-2-chloro-N-(1-phenylethyl)pyridine-3-sulfonamide

by Zhixu Zhou, Linwei Li, Ning Yan, Lei Du, Changshan Sun and Tiemin Sun

Molecules 2015, 20(11), 20926-20938; https://doi.org/10.3390/molecules201119740 - 24 Nov 2015

Cited by 5 | Viewed by 5751

Abstract

Pyridinesulfonamide is an important fragment which has a wide range of applications in novel drugs. R- and S-isomers of 5-bromo-2-chloro-N-(1-phenylethyl)pyridine-3-sulfonamide have been synthesized, and the stereostructures have been researched. Single crystals of both compounds were obtained for X-ray analysis, [...] Read more.

Pyridinesulfonamide is an important fragment which has a wide range of applications in novel drugs. R- and S-isomers of 5-bromo-2-chloro-N-(1-phenylethyl)pyridine-3-sulfonamide have been synthesized, and the stereostructures have been researched. Single crystals of both compounds were obtained for X-ray analysis, and the absolute configurations (ACs) have been further confirmed by electronic circular dichroism (ECD), optical rotation (OR) and quantum chemical calculations. The crystal structures and calculated geometries were extremely similar, which permitted a comparison of the relative reliabilities of ACs obtained by ECD analyses and theoretical simulation. In addition, the effect of stereochemistry on the PI3Kα kinase and anticancer activity were investigated. Compounds 10a and 10b inhibit the activity of PI3Kα kinase with IC₅₀ values of 1.08 and 2.69 μM, respectively. Furthermore, molecular docking was performed to analyze the binding modes of R- and S-isomers. Full article

(This article belongs to the Section Medicinal Chemistry)

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Graphical abstract

968 KiB

Open AccessArticle

New Flavones, a 2-(2-Phenylethyl)-4H-chromen-4-one Derivative, and Anti-Inflammatory Constituents from the Stem Barks of Aquilaria sinensis

by Sin-Ling Wang, Tsong-Long Hwang, Mei-Ing Chung, Ping-Jyun Sung, Chih-Wen Shu, Ming-Jen Cheng and Jih-Jung Chen

Molecules 2015, 20(11), 20912-20925; https://doi.org/10.3390/molecules201119736 - 24 Nov 2015

Cited by 38 | Viewed by 7634

Abstract

In the current study, two new flavones, 4′-O-geranyltricin (1) and 3′-O-geranylpolloin (2), and a new 2-(2-phenylethyl)-4H-chromen-4-one derivative, 7-hydroxyl-6-methoxy-2-(2-phenylethyl)chromone (3), have been isolated from the stem barks of A. sinensis, together [...] Read more.

In the current study, two new flavones, 4′-O-geranyltricin (1) and 3′-O-geranylpolloin (2), and a new 2-(2-phenylethyl)-4H-chromen-4-one derivative, 7-hydroxyl-6-methoxy-2-(2-phenylethyl)chromone (3), have been isolated from the stem barks of A. sinensis, together with 21 known compounds 4–24. The structures of new compounds 1–3 were determined through spectroscopic and MS analyses. Compounds 2, 3, 5, 6, and 8–10 exhibited inhibition (IC₅₀ ≤ 12.51 μM) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 3, 6, 8, 10, and 19 inhibited fMLP/CB-induced elastase release with IC₅₀ values ≤ 15.25 μM. This investigation reveals bioactive isolates (especially 2, 3, 5, 6, 8, 9, 10, and 19) could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases. Full article

(This article belongs to the Section Natural Products Chemistry)

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2561 KiB

Open AccessArticle

Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root

by Xuejing Jia, Chao Zhang, Jie Hu, Muxue He, Jiaolin Bao, Kai Wang, Peng Li, Meiwan Chen, Jianbo Wan, Huanxing Su, Qingwen Zhang and Chengwei He

Molecules 2015, 20(11), 20901-20911; https://doi.org/10.3390/molecules201119734 - 23 Nov 2015

Cited by 21 | Viewed by 6547

Abstract

Box-Behnken design (BBD), one of the most common response surface methodology (RSM) methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM). The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. [...] Read more.

Box-Behnken design (BBD), one of the most common response surface methodology (RSM) methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM). The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95% ± 0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessReview

Quaternary Alkylammonium Conjugates of Steroids: Synthesis, Molecular Structure, and Biological Studies

by Bogumił Brycki, Hanna Koenig and Tomasz Pospieszny

Molecules 2015, 20(11), 20887-20900; https://doi.org/10.3390/molecules201119735 - 23 Nov 2015

Cited by 15 | Viewed by 7610

Abstract

The methods of synthesis as well as physical, spectroscopic (¹H-NMR, ¹³C-NMR, and FT-IR, ESI-MS), and biological properties of quaternary and dimeric quaternary alkylammonium conjugates of steroids are presented. The results were contrasted with theoretical calculations (PM5 methods) and potential pharmacological [...] Read more.

The methods of synthesis as well as physical, spectroscopic (¹H-NMR, ¹³C-NMR, and FT-IR, ESI-MS), and biological properties of quaternary and dimeric quaternary alkylammonium conjugates of steroids are presented. The results were contrasted with theoretical calculations (PM5 methods) and potential pharmacological properties (PASS). Alkylammonium sterols exhibit a broad spectrum of antimicrobial activity comparable to squalamine. Full article

(This article belongs to the Section Organic Chemistry)

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Open AccessArticle

Synthesis of Tertiary and Quaternary Amine Derivatives from Wood Resin as Chiral NMR Solvating Agents

by Tiina Laaksonen, Sami Heikkinen and Kristiina Wähälä

Molecules 2015, 20(11), 20873-20886; https://doi.org/10.3390/molecules201119732 - 23 Nov 2015

Cited by 12 | Viewed by 8168

Abstract

Chiral tertiary and quaternary amine solvating agents for NMR spectroscopy were synthesized from the wood resin derivative (+)-dehydroabietylamine (2). The resolution of enantiomers of model compounds [Mosher’s acid (3) and its n-Bu₄N salt (4)] [...] Read more.

Chiral tertiary and quaternary amine solvating agents for NMR spectroscopy were synthesized from the wood resin derivative (+)-dehydroabietylamine (2). The resolution of enantiomers of model compounds [Mosher’s acid (3) and its n-Bu₄N salt (4)] (guests) by (+)-dehydroabietyl-N,N-dimethylmethanamine (5) and its ten different ammonium salts (hosts) was studied. The best results with 3 were obtained using 5 while with 4 the best enantiomeric resolution was obtained using (+)-dehydroabietyl-N,N-dimethylmethanaminium bis(trifluoromethane-sulfonimide) (6). The compounds 5 and 6 showed a 1:1 complexation behaviour between the host and guest. The capability of 5 and 6 to recognize the enantiomers of various α-substituted carboxylic acids and their n-Bu₄N salts in enantiomeric excess (ee) determinations was demonstrated. A modification of the RES-TOCSY NMR pulse sequence is described, allowing the enhancement of enantiomeric discrimination when the resolution of multiplets is insufficient. Full article

(This article belongs to the Section Organic Chemistry)

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Open AccessReview

Phytochelators Intended for Clinical Use in Iron Overload, Other Diseases of Iron Imbalance and Free Radical Pathology

by Christina N. Kontoghiorghe, Annita Kolnagou and George J. Kontoghiorghes

Molecules 2015, 20(11), 20841-20872; https://doi.org/10.3390/molecules201119725 - 23 Nov 2015

Cited by 51 | Viewed by 9842

Abstract

Iron chelating drugs are primarily and widely used in the treatment of transfusional iron overload in thalassaemia and similar conditions. Recent in vivo and clinical studies have also shown that chelators, and in particular deferiprone, can be used effectively in many conditions involving [...] Read more.

Iron chelating drugs are primarily and widely used in the treatment of transfusional iron overload in thalassaemia and similar conditions. Recent in vivo and clinical studies have also shown that chelators, and in particular deferiprone, can be used effectively in many conditions involving free radical damage and pathology including neurodegenerative, renal, hepatic, cardiac conditions and cancer. Many classes of phytochelators (Greek: phyto (φυτό)—plant, chele (χηλή)—claw of the crab) with differing chelating properties, including plant polyphenols resembling chelating drugs, can be developed for clinical use. The phytochelators mimosine and tropolone have been identified to be orally active and effective in animal models for the treatment of iron overload and maltol for the treatment of iron deficiency anaemia. Many critical parameters are required for the development of phytochelators for clinical use including the characterization of the therapeutic targets, ADMET, identification of the therapeutic index and risk/benefit assessment by comparison to existing therapies. Phytochelators can be developed and used as main, alternative or adjuvant therapies including combination therapies with synthetic chelators for synergistic and or complimentary therapeutic effects. The development of phytochelators is a challenging area for the introduction of new pharmaceuticals which can be used in many diseases and also in ageing. The commercial and other considerations for such development have great advantages in comparison to synthetic drugs and could also benefit millions of patients in developing countries. Full article

(This article belongs to the Section Metabolites)

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Open AccessArticle

Identification of RNA Oligonucleotides Binding to Several Proteins from Potential G-Quadruplex Forming Regions in Transcribed Pre-mRNA

by Taiki Saito, Wataru Yoshida, Tomomi Yokoyama, Koichi Abe and Kazunori Ikebukuro

Molecules 2015, 20(11), 20832-20840; https://doi.org/10.3390/molecules201119733 - 23 Nov 2015

Cited by 7 | Viewed by 6809

Abstract

G-quadruplexes (G4s) are noncanonical DNA/RNA structures formed by guanine-rich sequences. Recently, G4s have been found not only in aptamers but also in the genomic DNA and transcribed RNA. In this study, we identified new RNA oligonucleotides working as aptamers by focusing on G4-forming [...] Read more.

G-quadruplexes (G4s) are noncanonical DNA/RNA structures formed by guanine-rich sequences. Recently, G4s have been found not only in aptamers but also in the genomic DNA and transcribed RNA. In this study, we identified new RNA oligonucleotides working as aptamers by focusing on G4-forming RNAs located within the pre-mRNA. We showed that the G4 in the 5′ UTR and first intron of VEGFA bound to the protein encoded in VEGFA gene, VEGF165, with high affinity. Moreover, G4-forming RNAs located within the PDGFA and the PDGFB introns bound to PDGF-AA and PDGF-BB, respectively, indicating that G4 in the pre-mRNA could be an aptamer. It had been reported that the putative G4-forming RNA sequences are located in some parts of most genes, thus our strategy for aptamer identification could be applicable to other proteins. It has been reported that some G4-forming RNAs in 5′ UTRs are involved in translation control; however, G4-forming excised intronic RNA function has not been revealed previously. Therefore, these findings could not only contribute to the identification of RNA aptamers but also provide new insights into the biological functioning of G4-forming RNAs located within intronic RNA sequences. Full article

(This article belongs to the Special Issue Aptamers: Past, Present, and Future)

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567 KiB

Open AccessCommunication

Two New Cyototoxic Cardenolides from the Whole Plants of Adonis multiflora Nishikawa & Koki Ito

by Jae-Woo Jung, Nam-In Baek, Jeon Hwang-Bo, Seung-Su Lee, Ji-Hae Park, Kyeong-Hwa Seo, Jung-Hwa Kwon, Eun-Ji Oh, Dae-Young Lee, In-Sik Chung and Myun-Ho Bang

Molecules 2015, 20(11), 20823-20831; https://doi.org/10.3390/molecules201119722 - 23 Nov 2015

Cited by 7 | Viewed by 5536

Abstract

A phytochemical investigation of the whole plants of Adonis multiflora Nishikawa & Koki Ito. resulted in the isolation and identification of two new cardenolides—adonioside A (1) and adonioside B (6)—as well as four known cardenolides: tupichinolide (2) [...] Read more.

A phytochemical investigation of the whole plants of Adonis multiflora Nishikawa & Koki Ito. resulted in the isolation and identification of two new cardenolides—adonioside A (1) and adonioside B (6)—as well as four known cardenolides: tupichinolide (2) oleandrine (3), cryptostigmin II (4), and cymarin (5). Their structures were elucidated on the basis of NMR, MS, and IR spectroscopic analyses. Compounds 1, 2, 5, and 6 showed significant cytotoxicity against six human cancer cell lines (HCT-116, HepG2, HeLa, SK-OV-3, and SK-MEL-5, and SK-BR-3). Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

A 7-Deazaadenosylaziridine Cofactor for Sequence-Specific Labeling of DNA by the DNA Cytosine-C5 Methyltransferase M.HhaI

by Falk Kunkel, Rudi Lurz and Elmar Weinhold

Molecules 2015, 20(11), 20805-20822; https://doi.org/10.3390/molecules201119723 - 23 Nov 2015

Cited by 12 | Viewed by 7092

Abstract

DNA methyltransferases (MTases) catalyze the transfer of the activated methyl group of the cofactor S-adenosyl-l-methionine (AdoMet or SAM) to the exocyclic amino groups of adenine or cytosine or the C5 ring atom of cytosine within specific DNA sequences. The DNA adenine-N6 MTase [...] Read more.

DNA methyltransferases (MTases) catalyze the transfer of the activated methyl group of the cofactor S-adenosyl-l-methionine (AdoMet or SAM) to the exocyclic amino groups of adenine or cytosine or the C5 ring atom of cytosine within specific DNA sequences. The DNA adenine-N6 MTase from Thermus aquaticus (M.TaqI) is also capable of coupling synthetic N-adenosylaziridine cofactor analogues to its target adenine within the double-stranded 5′-TCGA-3′ sequence. This M.TaqI-mediated coupling reaction was exploited to sequence-specifically deliver fluorophores and biotin to DNA using N-adenosylaziridine derivatives carrying reporter groups at the 8-position of the adenine ring. However, these 8-modified aziridine cofactors were poor substrates for the DNA cytosine-C5 MTase from Haemophilus haemolyticus (M.HhaI). Based on the crystal structure of M.HhaI in complex with a duplex oligodeoxynucleotide and the cofactor product, we synthesized a stable 7-deazaadenosylaziridine derivative with a biotin group attached to the 7-position via a flexible linker. This 7-modified aziridine cofactor can be efficiently used by M.HhaI for the direct, quantitative and sequence-specific delivery of biotin to the second cytosine within 5′-GCGC-3′ sequences in short duplex oligodeoxynucleotides and plasmid DNA. In addition, we demonstrate that biotinylation by M.HhaI depends on the methylation status of the target cytosine and, thus, could provide a method for cytosine-C5 DNA methylation detection in mammalian DNA. Full article

(This article belongs to the Special Issue Frontiers in Nucleic Acid Chemistry)

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5193 KiB

Open AccessReview

DNA Catalysis: The Chemical Repertoire of DNAzymes

by Marcel Hollenstein

Molecules 2015, 20(11), 20777-20804; https://doi.org/10.3390/molecules201119730 - 20 Nov 2015

Cited by 133 | Viewed by 17458

Abstract

Deoxyribozymes or DNAzymes are single-stranded catalytic DNA molecules that are obtained by combinatorial in vitro selection methods. Initially conceived to function as gene silencing agents, the scope of DNAzymes has rapidly expanded into diverse fields, including biosensing, diagnostics, logic gate operations, and the [...] Read more.

Deoxyribozymes or DNAzymes are single-stranded catalytic DNA molecules that are obtained by combinatorial in vitro selection methods. Initially conceived to function as gene silencing agents, the scope of DNAzymes has rapidly expanded into diverse fields, including biosensing, diagnostics, logic gate operations, and the development of novel synthetic and biological tools. In this review, an overview of all the different chemical reactions catalyzed by DNAzymes is given with an emphasis on RNA cleavage and the use of non-nucleosidic substrates. The use of modified nucleoside triphosphates (dN*TPs) to expand the chemical space to be explored in selection experiments and ultimately to generate DNAzymes with an expanded chemical repertoire is also highlighted. Full article

(This article belongs to the Special Issue Nanozymes and Beyond)

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Open AccessReview

Current Research on Antiepileptic Compounds

by Cheng-Xi Wei, Ming Bian and Guo-Hua Gong

Molecules 2015, 20(11), 20741-20776; https://doi.org/10.3390/molecules201119714 - 20 Nov 2015

Cited by 26 | Viewed by 8911

Abstract

Epilepsy affects about 1% of the world’s population. Due to the fact all antiepileptic drugs (AEDs) have some undesirable side effects and about 30% of epileptic patients are not seizure-free with the existing AEDs, there is still an urgent need for the development [...] Read more.

Epilepsy affects about 1% of the world’s population. Due to the fact all antiepileptic drugs (AEDs) have some undesirable side effects and about 30% of epileptic patients are not seizure-free with the existing AEDs, there is still an urgent need for the development of more effective and safer AEDs. Based on our research work on antiepileptic compounds and other references in recent years, this review covers the reported work on antiepileptic compounds which are classified according to their structures. This review summarized 244 significant anticonvulsant compounds which are classified by functional groups according to the animal model data, although there are some limitations in the data. This review highlights the properties of new compounds endowed with promising antiepileptic properties, which may be proven to be more effective and selective, and possibly free of unwanted side effects. The reviewed compounds represent an interesting possibility to overcome refractory seizures and to reduce the percentage of patients with a poor response to drug therapy. Full article

(This article belongs to the Section Medicinal Chemistry)

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Open AccessArticle

Condensation of Diacetyl with Alkyl Amines: Synthesis and Reactivity of p-Iminobenzoquinones and p-Diiminobenzoquinones

by Carlos Espinoza-Hicks, Rafael Bautista, Saúl Frias-Puente, Vanessa Pelayo, Eder I. Martínez-Mora, Francisco Delgado and Joaquín Tamariz

Molecules 2015, 20(11), 20719-20740; https://doi.org/10.3390/molecules201119716 - 20 Nov 2015

Cited by 3 | Viewed by 8647

Abstract

Condensation reactions between diacetyl and α-branched primary alkylamines under mild and neutral conditions provided a mixture of 2,5-dimethylbenzoquinone(alkylimines), 2,5-dimethylbenzoquinone(bis-alkyldiimines), and N,N′-dialkyl-2,5-dimethylbenzene-1,4-diamines, which were efficiently separated as pure products by column chromatography. Both 2,5-dimethylbenzoquinone(alkylimines) and 2,5-dimethylbenzoquinone(bis-alkyldiimines) underwent [...] Read more.

Condensation reactions between diacetyl and α-branched primary alkylamines under mild and neutral conditions provided a mixture of 2,5-dimethylbenzoquinone(alkylimines), 2,5-dimethylbenzoquinone(bis-alkyldiimines), and N,N′-dialkyl-2,5-dimethylbenzene-1,4-diamines, which were efficiently separated as pure products by column chromatography. Both 2,5-dimethylbenzoquinone(alkylimines) and 2,5-dimethylbenzoquinone(bis-alkyldiimines) underwent an interchange of the alkylimino group when treated with anilines, followed by reductive aromatization, to provide diarylamines and 1,4-dianilinobenzenes, respectively. Evaluation was also made of the reactivity and selectivity of these compounds in the presence of anilines, thiophenols and alkylhalides. Full article

(This article belongs to the Section Organic Chemistry)

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Open AccessCommunication

An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis

by Fatemeh Rajabi, Diego Alves and Rafael Luque

Molecules 2015, 20(11), 20709-20718; https://doi.org/10.3390/molecules201119731 - 19 Nov 2015

Cited by 17 | Viewed by 6590

Abstract

The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss [...] Read more.

The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial. Full article

(This article belongs to the Special Issue Metal Nanocatalysts in Green Synthesis and Energy Applications)

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Open AccessArticle

Cinidium officinale and its Bioactive Compound, Butylidenephthalide, Inhibit Laser-Induced Choroidal Neovascularization in a Rat Model

by Yun Mi Lee, Yu Ri Lee, Jin Sook Kim, Young Ho Kim and Junghyun Kim

Molecules 2015, 20(11), 20699-20708; https://doi.org/10.3390/molecules201119728 - 19 Nov 2015

Cited by 7 | Viewed by 6120

Abstract

Choroidal neovascularization (CNV) is a common pathology in age-related macular degeneration. In this study, we evaluated in a rat model the effect of an extract of Cinidium officinale Makino and its bioactive compound, butylidenephthalide, on laser-induced CNV. Experimental CNV was induced in Long-Evans [...] Read more.

Choroidal neovascularization (CNV) is a common pathology in age-related macular degeneration. In this study, we evaluated in a rat model the effect of an extract of Cinidium officinale Makino and its bioactive compound, butylidenephthalide, on laser-induced CNV. Experimental CNV was induced in Long-Evans rats by laser photocoagulation. C. officinale extract (COE) and butylidenephthalide was intraperitoneally injected once per day for ten days after laser photocoagulation. Choroidal flat mounts were prepared to measure CNV areas and macrophage infiltration. We used a protein array to evaluate the expression levels of angiogenic factors. The CNV area and macrophage infiltration in COE-treated rats were significantly lower than in vehicle-treated rats. COE decreased the expression levels of IGFBP-1, MCP-1, PAI-1, and VEGF. Additionally, butylidenephthalide also inhibited the laser-induced CNV formation and macrophage infiltration and down-regulated the expression of IGFBP-1, MCP-1 and VEGF. These results suggest that COE exerts anti-angiogenic effects on laser-induced CNV by inhibiting the expression of IGFBP-1, MCP-1, and VEGF, indicating that anti-angiogenic activities of COE may be in part due to its bioactive compound, butylidenephthalide. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

Solvatochromic and Single Crystal Studies of Two Neutral Triarylmethane Dyes with a Quinone Methide Structure

by Katherine Chulvi, Ana M. Costero, Luis E. Ochando, Salvador Gil, José-Luis Vivancos and Pablo Gaviña

Molecules 2015, 20(11), 20688-20698; https://doi.org/10.3390/molecules201119724 - 19 Nov 2015

Cited by 4 | Viewed by 7057

Abstract

The crystal structure of two neutral triarylmethane dyes with a p-quinone methide core was determined by X-ray diffraction analysis. The spectroscopic characteristics of both compounds in 23 solvents with different polarities or hydrogen-bonding donor (HBD) abilities has been studied as a function of [...] Read more.

The crystal structure of two neutral triarylmethane dyes with a p-quinone methide core was determined by X-ray diffraction analysis. The spectroscopic characteristics of both compounds in 23 solvents with different polarities or hydrogen-bonding donor (HBD) abilities has been studied as a function of three solvatochromic parameters (E_T(30), π* and α). Both compounds 1 and 2 showed a pronounced bathochromic shift of the main absorption band on increasing solvent polarity and HBD ability. The correlation is better for compound 2 than for compound 1. The stronger effect and better correlation was observed for compound 2 with the increment of the solvent HBD ability (α parameter). Full article

(This article belongs to the Special Issue Photoactive Molecules)

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Open AccessReview

The Effect of Low Monotonic Doses of Zearalenone on Selected Reproductive Tissues in Pre-Pubertal Female Dogs—A Review

by Magdalena Gajęcka, Łukasz Zielonka and Maciej Gajęcki

Molecules 2015, 20(11), 20669-20687; https://doi.org/10.3390/molecules201119726 - 19 Nov 2015

Cited by 25 | Viewed by 7022

Abstract

The growing interest in toxic substances combined with advancements in biological sciences has shed a new light on the problem of mycotoxins contaminating feeds and foods. An interdisciplinary approach was developed by identifying dose-response relationships in key research concepts, including the low dose [...] Read more.

The growing interest in toxic substances combined with advancements in biological sciences has shed a new light on the problem of mycotoxins contaminating feeds and foods. An interdisciplinary approach was developed by identifying dose-response relationships in key research concepts, including the low dose theory of estrogen-like compounds, hormesis, NOAEL dose, compensatory response and/or food tolerance, and effects of exposure to undesirable substances. The above considerations increased the researchers’ interest in risk evaluation, namely: (i) clinical symptoms associated with long-term, daily exposure to low doses of a toxic compound; and (ii) dysfunctions at cellular or tissue level that do not produce clinical symptoms. Research advancements facilitate the extrapolation of results and promote the use of novel tools for evaluating the risk of exposure, for example exposure to zearalenone in pre-pubertal female dogs. The arguments presented in this paper suggest that low doses of zearalenone in commercial feeds stimulate metabolic processes and increase weight gains. Those processes are accompanied by lower proliferation rates in the ovaries, neoangiogenesis and vasodilation in the ovaries and the uterus, changes in the steroid hormone profile, and changes in the activity of hydroxysteroid dehydrogenases. All of the above changes result from exogenous hyperestrogenizm. Full article

(This article belongs to the Special Issue Natural Toxins)

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Open AccessArticle

Cyclovirobuxine D Inhibits Cell Proliferation and Induces Mitochondria-Mediated Apoptosis in Human Gastric Cancer Cells

by Jie Wu, Zhujun Tan, Jian Chen and Cheng Dong

Molecules 2015, 20(11), 20659-20668; https://doi.org/10.3390/molecules201119729 - 19 Nov 2015

Cited by 20 | Viewed by 5942

Abstract

Gastric cancer is one of the most common malignant cancers, with high death rates, poor prognosis and limited treatment methods. Cyclovirobuxine D (CVB-D) is the main active component of the traditional Chinese medicine Buxus microphylla. In the present study, we test the effects [...] Read more.

Gastric cancer is one of the most common malignant cancers, with high death rates, poor prognosis and limited treatment methods. Cyclovirobuxine D (CVB-D) is the main active component of the traditional Chinese medicine Buxus microphylla. In the present study, we test the effects of CVB-D on gastric cancer cells and the underlying mechanisms of action. CVB-D reduced cell viability and colony formation ability of MGC-803 and MKN28 cells in a time- and concentration-dependent manner. Flow cytometry showed that cell cycle of CVB-D treated cells was arrested at the S-phase. CVB-D also induced apoptosis in MGC-803 and MKN28 cells, especially early stage apoptosis. Furthermore, mitochondria membrane potential (Δψm) was reduced and apoptosis-related proteins, cleaved Caspase-3 and Bax/Bcl-2, were up-regulated in CVB-D-treated MGC-803 and MKN28 cells. Taken together, our studies found that CVB-D plays important roles in inhibition of gastric tumorigenesis via arresting cell cycle and inducing mitochondria-mediated apoptosis, suggesting the potential application of CVB-D in gastric cancer therapy. Full article

(This article belongs to the Section Medicinal Chemistry)

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Open AccessArticle

New Diethyl Ammonium Salt of Thiobarbituric Acid Derivative: Synthesis, Molecular Structure Investigations and Docking Studies

by Assem Barakat, Abdullah Mohammed Al-Majid, Saied M. Soliman, Gehad Lotfy, Hazem A. Ghabbour, Hoong-Kun Fun, Abdul Wadood, Ismail Warad and Joseph C. Sloop

Molecules 2015, 20(11), 20642-20658; https://doi.org/10.3390/molecules201119710 - 19 Nov 2015

Cited by 13 | Viewed by 6895

Abstract

The synthesis of the new diethyl ammonium salt of diethylammonium(E)-5-(1,5-bis(4-fluorophenyl)-3-oxopent-4-en-1-yl)-1,3-diethyl-4,6-dioxo-2-thioxohexaydropyrimidin-5-ide 3 via a regioselective Michael addition of N,N-diethylthiobarbituric acid 1 to dienone 2 is described. In 3, the carboanion of the thiobarbituric moiety is stabilized [...] Read more.

The synthesis of the new diethyl ammonium salt of diethylammonium(E)-5-(1,5-bis(4-fluorophenyl)-3-oxopent-4-en-1-yl)-1,3-diethyl-4,6-dioxo-2-thioxohexaydropyrimidin-5-ide 3 via a regioselective Michael addition of N,N-diethylthiobarbituric acid 1 to dienone 2 is described. In 3, the carboanion of the thiobarbituric moiety is stabilized by the strong intramolecular electron delocalization with the adjacent carbonyl groups and so the reaction proceeds without any cyclization. The molecular structure investigations of 3 were determined by single-crystal X-ray diffraction as well as DFT computations. The theoretically calculated (DFT/B3LYP) geometry agrees well with the crystallographic data. The effect of fluorine replacement by chlorine atoms on the molecular structure aspects were investigated using DFT methods. Calculated electronic spectra showed a bathochromic shift of the π-π* transition when fluorine is replaced by chlorine. Charge decomposition analyses were performed to study possible interaction between the different fragments in the studied systems. Molecular docking simulations examining the inhibitory nature of the compound show an anti-diabetic activity with Pa (probability of activity) value of 0.229. Full article

(This article belongs to the Section Medicinal Chemistry)

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Open AccessReview

Ursolic Acid—A Pentacyclic Triterpenoid with a Wide Spectrum of Pharmacological Activities

by Łukasz Woźniak, Sylwia Skąpska and Krystian Marszałek

Molecules 2015, 20(11), 20614-20641; https://doi.org/10.3390/molecules201119721 - 19 Nov 2015

Cited by 307 | Viewed by 22605

Abstract

Ursolic acid (UA) is a natural terpene compound exhibiting many pharmaceutical properties. In this review the current state of knowledge about the health-promoting properties of this widespread, biologically active compound, as well as information about its occurrence and biosynthesis are presented. Particular attention [...] Read more.

Ursolic acid (UA) is a natural terpene compound exhibiting many pharmaceutical properties. In this review the current state of knowledge about the health-promoting properties of this widespread, biologically active compound, as well as information about its occurrence and biosynthesis are presented. Particular attention has been paid to the application of ursolic acid as an anti-cancer agent; it is worth noticing that clinical tests suggesting the possibility of practical use of UA have already been conducted. Amongst other pharmacological properties of UA one can mention protective effect on lungs, kidneys, liver and brain, anti-inflammatory properties, anabolic effects on skeletal muscles and the ability to suppress bone density loss leading to osteoporosis. Ursolic acid also exhibits anti-microbial features against numerous strains of bacteria, HIV and HCV viruses and Plasmodium protozoa causing malaria. Full article

(This article belongs to the Special Issue Dietary Bioactive Compounds: Metabolism, Mechanisms and Translational Significance for Health and Prevention of Diseases)

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Open AccessReview

Immobilization of Metal Hexacyanoferrate Ion-Exchangers for the Synthesis of Metal Ion Sorbents—A Mini-Review

by Thierry Vincent, Chloë Vincent and Eric Guibal

Molecules 2015, 20(11), 20582-20613; https://doi.org/10.3390/molecules201119718 - 19 Nov 2015

Cited by 112 | Viewed by 12571

Abstract

Metal hexacyanoferrates are very efficient sorbents for the recovery of alkali and base metal ions (including radionuclides such as Cs). Generally produced by the direct reaction of metal salts with potassium hexacyanoferrate (the precursors), they are characterized by ion-exchange and structural properties that [...] Read more.

Metal hexacyanoferrates are very efficient sorbents for the recovery of alkali and base metal ions (including radionuclides such as Cs). Generally produced by the direct reaction of metal salts with potassium hexacyanoferrate (the precursors), they are characterized by ion-exchange and structural properties that make then particularly selective for Cs(I), Rb(I) and Tl(I) recovery (based on their hydrated ionic radius consistent with the size of the ion-exchanger cage), though they can bind also base metals. The major drawback of these materials is associated to their nanometer or micrometer size that makes them difficult to recover in large-size continuous systems. For this reason many techniques have been designed for immobilizing these ion-exchangers in suitable matrices that can be organic (mainly polymers and biopolymers) or inorganic (mineral supports), carbon-based matrices. This immobilization may proceed by in situ synthesis or by entrapment/encapsulation. This mini-review reports some examples of hybrid materials synthesized for the immobilization of metal hexacyanoferrate, the different conditionings of these composite materials and, briefly, the parameters to take into account for their optimal design and facilitated use. Full article

(This article belongs to the Special Issue 20th Anniversary of Molecules—Recent Advances in Organic Chemistry)

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Open AccessArticle

Ardipusilloside-I Metabolites from Human Intestinal Bacteria and Their Antitumor Activity

by Wei-Yu Cao, Ya-Nan Wang, Peng-Yuan Wang, Wan Lei, Bin Feng and Xiao-Juan Wang

Molecules 2015, 20(11), 20569-20581; https://doi.org/10.3390/molecules201119719 - 19 Nov 2015

Cited by 12 | Viewed by 5792

Abstract

Ardipusilloside-I (ADS-I) is a triterpenoid saponin extracted from Ardisia pusilla DC, and has been demonstrated to have potent antitumor activity. However, ADS-I metabolism in humans has not been investigated. In this study, we studied the biotransformation of ADS-I in human intestinal bacteria, and [...] Read more.

Ardipusilloside-I (ADS-I) is a triterpenoid saponin extracted from Ardisia pusilla DC, and has been demonstrated to have potent antitumor activity. However, ADS-I metabolism in humans has not been investigated. In this study, we studied the biotransformation of ADS-I in human intestinal bacteria, and examined the in vitro antitumor activity of the major metabolites. Ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was used to detect ADS-I biotransformation products, and their chemical structures were identified by high performance liquid chromatography–nuclear magnetic resonance (HPLC–NMR). The antitumor activity of the major metabolites was determined by the MTT assay. Here, we show that main reaction seen in the metabolism of ADS-I in human intestinal bacteria was deglycosylation, which produced a total of four metabolites. The structures of the two major metabolites M1 and M2 were confirmed by using NMR. MTT assay showed that ADS-I metabolites M1 and M2 have the same levels of inhibitory activities as ADS-I in cultured SMMC-7721 cells and MCF-7 cells. In conclusion, this study demonstrates deglycosylation as a primary pathway of ADS-I metabolism in human intestinal bacteria, and suggests that the pharmacological activity of ADS-I may be mediated, at least in part, by its metabolites. Full article

(This article belongs to the Special Issue New Technologies for the Recovery of Natural Products)

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Open AccessReview

Recent Advances in Developing Inhibitors for Hypoxia-Inducible Factor Prolyl Hydroxylases and Their Therapeutic Implications

by So Yeon Kim and Eun Gyeong Yang

Molecules 2015, 20(11), 20551-20568; https://doi.org/10.3390/molecules201119717 - 19 Nov 2015

Cited by 60 | Viewed by 14066

Abstract

Hypoxia-inducible factor (HIF) prolyl hydroxylases (PHDs) are members of the 2-oxoglutarate dependent non-heme iron dioxygenases. Due to their physiological roles in regulation of HIF-1α stability, many efforts have been focused on searching for selective PHD inhibitors to control HIF-1α levels for therapeutic applications. [...] Read more.

Hypoxia-inducible factor (HIF) prolyl hydroxylases (PHDs) are members of the 2-oxoglutarate dependent non-heme iron dioxygenases. Due to their physiological roles in regulation of HIF-1α stability, many efforts have been focused on searching for selective PHD inhibitors to control HIF-1α levels for therapeutic applications. In this review, we first describe the structure of PHD2 as a molecular basis for structure-based drug design (SBDD) and various experimental methods developed for measuring PHD activity. We further discuss the current status of the development of PHD inhibitors enabled by combining SBDD approaches with high-throughput screening. Finally, we highlight the clinical implications of small molecule PHD inhibitors. Full article

(This article belongs to the Special Issue Chemoinformatics)

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Open AccessArticle

Agrimonia eupatoria L. and Cynara cardunculus L. Water Infusions: Phenolic Profile and Comparison of Antioxidant Activities

by Anika Kuczmannová, Peter Gál, Lenka Varinská, Jakub Treml, Ivan Kováč, Martin Novotný, Tomáš Vasilenko, Stefano Dall’Acqua, Milan Nagy and Pavel Mučaji

Molecules 2015, 20(11), 20538-20550; https://doi.org/10.3390/molecules201119715 - 18 Nov 2015

Cited by 31 | Viewed by 7414

Abstract

Reactive oxygen species (ROS) are highly considered in the ethiopathogenesis of different pathological conditions because they may cause significant damage to cells and tissues. In this paper, we focused on potential antioxidant properties of two medical plants such as the Agrimonia eupatoria L. [...] Read more.

Reactive oxygen species (ROS) are highly considered in the ethiopathogenesis of different pathological conditions because they may cause significant damage to cells and tissues. In this paper, we focused on potential antioxidant properties of two medical plants such as the Agrimonia eupatoria L. and Cynara cardunculus L. Both plants have previously been studied for their pharmacological activities, especially as hepatoprotective and hypoglycemic activities. It has been suggested, that their effects are related to the antioxidant properties of polyphenols, which are dominant compounds of the plants’ extracts. In the present study HPLC-MS analysis of water infusion was performed allowing the identification of several phenolic constituents. Furthermore, antioxidant effects of the two extracts were compared showing higher effects for agrimony extract compared to artichoke. Thus, agrimony was selected for the in vivo study using the skin flap viability model. In conclusion, our results provide evidence that the A. eupatoria extract may be a valuable source of polyphenols to be studied for the future development of supplements useful in the prevention of diseases linked to oxidative stress. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

Analysis of the Constituents in “Zhu She Yong Xue Shuan Tong” by Ultra High Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry Combined with Preparative High Performance Liquid Chromatography

by Lin-Lin Wang, Li-Feng Han, He-Shui Yu, Mang-Mang Sang, Er-Wei Liu, Yi Zhang, Shi-Ming Fang, Tao Wang and Xiu-Mei Gao

Molecules 2015, 20(11), 20518-20537; https://doi.org/10.3390/molecules201119712 - 18 Nov 2015

Cited by 23 | Viewed by 7680

Abstract

“Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST), consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight [...] Read more.

“Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST), consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) combined with preparative high performance liquid chromatography (PHPLC) method was developed to rapidly identify both major and minor saponins in ZSYXST. Some high content components were removed through PHPLC in order to increase the sensitivity of the trace saponins. Then, specific characteristic fragment ions in both positive and negative mode were utilized to determine the types of aglycone, saccharide, as well as the saccharide chain linkages. As a result, 94 saponins, including 20 pairs of isomers and ten new compounds, which could represent higher than 98% components in ZSYXST, were identified or tentatively identified in commercial ZSYXST samples. Full article

(This article belongs to the Section Natural Products Chemistry)

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2048 KiB

Open AccessReview

Redox Species of Redox Flow Batteries: A Review

by Feng Pan and Qing Wang

Molecules 2015, 20(11), 20499-20517; https://doi.org/10.3390/molecules201119711 - 18 Nov 2015

Cited by 185 | Viewed by 23803

Abstract

Due to the capricious nature of renewable energy resources, such as wind and solar, large-scale energy storage devices are increasingly required to make the best use of the renewable power. The redox flow battery is considered suitable for large-scale applications due to its [...] Read more.

Due to the capricious nature of renewable energy resources, such as wind and solar, large-scale energy storage devices are increasingly required to make the best use of the renewable power. The redox flow battery is considered suitable for large-scale applications due to its modular design, good scalability and flexible operation. The biggest challenge of the redox flow battery is the low energy density. The redox active species is the most important component in redox flow batteries, and the redox potential and solubility of redox species dictate the system energy density. This review is focused on the recent development of redox species. Different categories of redox species, including simple inorganic ions, metal complexes, metal-free organic compounds, polysulfide/sulfur and lithium storage active materials, are reviewed. The future development of redox species towards higher energy density is also suggested. Full article

(This article belongs to the Special Issue Molecular Engineering for Electrochemical Power Sources)

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Open AccessArticle

Chemical Composition and in-Vitro Evaluation of the Antimicrobial and Antioxidant Activities of Essential Oils Extracted from Seven Eucalyptus Species

by Abdul Ghaffar, Muhammad Yameen, Shumaila Kiran, Shagufta Kamal, Fatima Jalal, Bushra Munir, Sadaf Saleem, Naila Rafiq, Aftab Ahmad, Iram Saba and Abdul Jabbar

Molecules 2015, 20(11), 20487-20498; https://doi.org/10.3390/molecules201119706 - 18 Nov 2015

Cited by 73 | Viewed by 9667

Abstract

Eucalyptus is well reputed for its use as medicinal plant around the globe. The present study was planned to evaluate chemical composition, antimicrobial and antioxidant activity of the essential oils (EOs) extracted from seven Eucalyptus species frequently found in South East Asia (Pakistan). [...] Read more.

Eucalyptus is well reputed for its use as medicinal plant around the globe. The present study was planned to evaluate chemical composition, antimicrobial and antioxidant activity of the essential oils (EOs) extracted from seven Eucalyptus species frequently found in South East Asia (Pakistan). EOs from Eucalyptus citriodora, Eucalyptus melanophloia, Eucalyptus crebra, Eucalyptus tereticornis, Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus microtheca were extracted from leaves through hydrodistillation. The chemical composition of the EOs was determined through GC-MS-FID analysis. The study revealed presence of 31 compounds in E. citriodora and E. melanophloia, 27 compounds in E. crebra, 24 compounds in E. tereticornis, 10 compounds in E. globulus, 13 compounds in E. camaldulensis and 12 compounds in E. microtheca. 1,8-Cineole (56.5%), α-pinene (31.4%), citrinyl acetate (13.3%), eugenol (11.8%) and terpenene-4-ol (10.2%) were the highest principal components in these EOs. E. citriodora exhibited the highest antimicrobial activity against the five microbial species tested (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Aspergillus niger and Rhizopus solani). Gram positive bacteria were found more sensitive than Gram negative bacteria to all EOs. The diphenyl-1-picrylhydazyl (DPPH) radical scavenging activity and percentage inhibition of linoleic acid oxidation were highest in E. citriodora (82.1% and 83.8%, respectively) followed by E. camaldulensis (81.9% and 83.3%, respectively). The great variation in chemical composition of EOs from Eucalyptus, highlight its potential for medicinal and nutraceutical applications. Full article

(This article belongs to the Section Medicinal Chemistry)

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Open AccessReview

Relationship between Structure and Conformational Change of the Vitamin D Receptor Ligand Binding Domain in 1α,25-Dihydroxyvitamin D3 Signaling

by Lin-Yan Wan, Yan-Qiong Zhang, Meng-Di Chen, You-Qin Du, Chang-Bai Liu and Jiang-Feng Wu

Molecules 2015, 20(11), 20473-20486; https://doi.org/10.3390/molecules201119713 - 18 Nov 2015

Cited by 14 | Viewed by 5750

Abstract

Vitamin D Receptor (VDR) belongs to the nuclear receptor (NR) superfamily. Whereas the structure of the ligand binding domain (LBD) of VDR has been determined in great detail, the role of its amino acid residues in stabilizing the structure and ligand triggering conformational [...] Read more.

Vitamin D Receptor (VDR) belongs to the nuclear receptor (NR) superfamily. Whereas the structure of the ligand binding domain (LBD) of VDR has been determined in great detail, the role of its amino acid residues in stabilizing the structure and ligand triggering conformational change is still under debate. There are 13 α-helices and one β-sheet in the VDR LBD and they form a three-layer sandwich structure stabilized by 10 residues. Thirty-six amino acid residues line the ligand binding pocket (LBP) and six of these residues have hydrogen-bonds linking with the ligand. In 1α,25-dihydroxyvitamin D₃ signaling, H3 and H12 play an important role in the course of conformational change resulting in the provision of interfaces for dimerization, coactivator (CoA), corepressor (CoR), and hTAF_II 28. In this paper we provide a detailed description of the amino acid residues stabilizing the structure and taking part in conformational change of VDR LBD according to functional domains. Full article

(This article belongs to the Section Bioorganic Chemistry)

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Open AccessArticle

Variation in Phenolics, Flavanoids, Antioxidant and Tyrosinase Inhibitory Activity of Peach Blossoms at Different Developmental Stages

by Jie-Chao Liu, Zhong-Gao Jiao, Wen-Bo Yang, Chun-Ling Zhang, Hui Liu and Zhen-Zhen Lv

Molecules 2015, 20(11), 20460-20472; https://doi.org/10.3390/molecules201119709 - 18 Nov 2015

Cited by 17 | Viewed by 6283

Abstract

Peach blossoms were harvested and classified into six developmental stages: (I) bud emerging stage; (II) middle bud stage; (III) large bud stage; (IV) initial-flowering stage; (V) full-flowering stage; and (VI) end-flowering stage. The contents of total phenolics, flavanoids, individual phenolic compounds as well [...] Read more.

Peach blossoms were harvested and classified into six developmental stages: (I) bud emerging stage; (II) middle bud stage; (III) large bud stage; (IV) initial-flowering stage; (V) full-flowering stage; and (VI) end-flowering stage. The contents of total phenolics, flavanoids, individual phenolic compounds as well as antioxidant and tyrosinase inhibitory activity of peach blossoms at different developmental stages were investigated. The total phenolic contents varied from 149.80 to 74.80 mg chlorogenic acid equivalents/g dry weight (DW), and the total flavanoid contents ranged from 93.03 to 44.06 mg rutin equivalents/g DW. Both the contents of total phenolics and flavanoids decreased during blossom development. Chlorogenic acid was the predominant component, accounting for 62.08%–71.09% of the total amount of identified phenolic compounds in peach blossom. The antioxidant capacities determined by different assays and tyrosinase inhibitory activity also showed descending patterns during blossom development. Significant correlations were observed between antioxidant capacities with contents of total phenolics and total flavanoids as well as chlorogenic acid, cinnamic acid and kaempferol-3-O-galactoside, while the tyrosinase inhibitory activity had lower correlations with total phenolics and total flavanoids as well as chlorogenic acid, quercetin-3-O-rhamnoside, kaempferol-3-O-galactoside and cinnamic acid. The antioxidant activities of peach blossom seemed to be more dependent on the phenolic compounds than tyrosinase inhibitory activity. Full article

(This article belongs to the Section Natural Products Chemistry)

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