Flavonoid Glycosides from Terminalia catappa L.

Under the inhibition of Cu⁺²‐induced LDL oxidation‐guided fractionation, two new flavone glycosides with galloyl substitution were isolated from the dried fallen leaves of Terminalia catappa L. Their structures were established as apigenin 6‐C‐(2″‐O‐galloyl)‐β‐D‐glucopyranoside ( 1 ) and apigenin 8‐C‐(2″‐O‐galloyl)‐β‐D‐glucopyranoside ( 2 ), together with four known flavone glycosides, isovitexin, vitexin, isoorientin, and rutin, on the basis of spectroscopic method. Compounds 1 and 2 showed significant antioxidative effects. Their IC₅₀ were 2.1 and 4.5 μM, respectively.     

Tannins and Related Compounds from Quisqualis Indica

Continuous exploration of the chemical constituents of Combretaceous plants has led to the discovery of two novel ellagitannins, quisqualin A ( 1 ) and quisqualin B ( 2 ), from the fruits of Quisqualis indica. A total of twenty-one other tannins were also isolated from either the fruits or leaves of Q. indica. including [I] eleven ellagitannins: 2,3-(S)-HHDP-D-glucose ( 3 ), 2,3-(S)-HHDP-4-O-galloyl-D-glucose ( 4 ), 2,3-(S)-HHDP-6-O-galloyl-D-glucose ( 5 ), 2,3-(S)-HHDPA6-di-O-galloyl-D-glucose ( 6 ). pedunculagin ( 7 ), punicalagin ( 8 ), eugeniin ( 9 ), 1-desgalloyleugeniin ( 10 ), casuariin ( 11 ), 5-desgalloylstachyurin ( 12 ), castalagin ( 13 ); [II] five gallotannins-. 6-O-galloyl-D-glucose ( 14 ), 1,6-di-O-galloyl-β-D-glucose ( 15 ), 2,3-di-O-galloyl-D-glucose ( 16 ), 3,4-di-O-galloyl-D-glucose ( 17 ), 4,6-di-O-galloyl-D-glucose ( 18 ); [III] four phenol-carboxylic acids: gallic acid ( 19 ), ellagic acid ( 20 ), flavogallonic acid ( 21 ), brevifolin carboxylic acid ( 22 ) and [IV] one other hydrolyzable tannin: punicalin ( 23 ).     

Structural Transformation and Creativity Induced by Biological Agents during Fermentation of Edible Nuts from Terminalia catappa

Terminalia catappa L. (tropical almond) is a nutritious fruit found mainly in the tropics. This study is aimed to establish the naturally biotransformed molecules and identify the probiotic agents facilitating the fermentation. The aqueous extracts from both the unfermented and fermented T. catappa nuts were subjected to gas chromatography/mass spectrometry (GC/MS) analysis. Syringol (6.03%), glutamine (1.71%), methyl laurate (1.79%), methyl palmitate (1.53%), palmitic acid (5.20%), palmitoleic acid (2.80%), and methyl oleate (2.97%) were detected in the unfermented nuts of the T. catappa. Additionally, two of these natural compounds (palmitic acid (4.19%) and palmitoleic acid (1.48%)) survived the fermentation process to emerge in the fermented seeds. The other natural compounds were biotransformed into 2,3-butanediol (1.81%), butyric acid (16.20%), propane-1,3-diol (19.66%), neoheptanol (2.89%), 2-piperidinone (6.63%), palmitoleic acid (1.18%), formamide, n-(p-hydroxyphenethyl)- (2.80%), and cis-vaccenic acid (1.69%) that newly emerged in the fermented seeds. The phytochemical compounds are likely carbon sources for the organisms facilitating the biotransformed molecules and product production. Four (4) potential probiotic bacteria strains, namely, Probt B1a, Probt B2a, Probt B4a, and Probt B4b, were isolated from the fermented nut. Enterococcus faecum, and Enterococcus faecalis were the organisms identified as driving the fermentation of the seeds. All strains were gram-positive, catalase-negative, and non-hemolytic, which suggests their harmless nature. N-(p-hydroxyphenethyl)-) was associated with fermentation for the first time, and neoheptanol was discovered as the main alcoholic molecule formed during the fermentation of the seeds. This fermentation is a handy tool for bio-transforming compounds in raw food sources into compounds with nutritious and therapeutic potentials.     

A New Benzylisoquinoline Alkaloid from Sabia parviflora

A new benzylisoquinoline alkaloid,1,2,3,4-tetrahydro-5-hydroxyl-8-methoxyl-2-methyl-4′-methoxyl-benzylisoquinoline,was isolated from the arial parts of Sabia parviflora. Its structure was established on the basis of spectral analysis.     

Two New Pentacyclic Triterpenes from Sabia parviflora

Two new pentacyclic triterpene acids,1α,3β-dihydroxyl-olean-12-en-28-oic acid and 1α，2α,3β-trihydroxyl-olean-12-en-28-oic acid, were isolated from the arial parts of Sabia parviflora.     

Optimization of Ultrasound-Assisted Extraction of Yields and Total Methoxyflavone Contents from Kaempferia parviflora Rhizomes

The major bioactive components of Kaempferia parviflora (KP) rhizomes, 3,5,7,3′,4′-pentamethoxyflavone (PMF), 5,7-dimethoxyflavone (DMF), and 5,7,4′-trimethoxyflavone (TMF), were chosen as the quantitative and qualitative markers for this plant material. In order to extract bioactive components (total methoxyflavones) from KP rhizomes, ultrasound-assisted extraction (UAE) was proposed as part of this study. Plackett–Burman design (PBD) and Box–Behnken design (BBD) were utilized to optimize the effects of UAE on extraction yields and total methoxyflavone contents in KP rhizomes. First, PBD was utilized to determine the effect of five independent variables on total yields and total methoxyflavone contents. The results indicated that the concentration of the extracting solvent (ethanol), the extraction time, and the ratio of solvent to solid were significant independent terms. Subsequently, BBD with three-level factorial experiments was used to optimize the crucial variables. It was discovered that the concentration of ethanol was the most influential variable on yields and total methoxyflavone contents. Optimum conditions for extraction yield were ethanol concentration (54.24% v/v), extraction time (25.25 min), and solvent-to-solid ratio (49.63 mL/g), while optimum conditions for total methoxyflavone content were ethanol concentration (95.00% v/v), extraction time (15.99 min), and solvent-to-solid ratio (50.00 mL/g). The relationship between the experimental and theoretical values was perfect, which proved that the regression models used were correct and that PBD and BBD were used to optimize the conditions in the UAE to obtain the highest yield and total methoxyflavone content in the KP rhizomes.     

Application of Cyclodextrins to the Extraction of Antioxidant Compounds from Olive Oil

Olive oil contains powerful antioxidant compounds which impart stability, contribute to various properties of it, and are valuable from the nutritional point of view. Their extraction with as mild conditions as possible led to its investigation using cyclodextrins as a tool. The inclusion ability of α-, β-, and γ-CD was estimated, and it has been demonstrated that the small cavity of α-CD as well as the wide one of γ-CD could enclose less effectively the antioxidant compounds of olive oil than the intermediate in shape cavity of β-CD. The highest yields of antioxidant compounds were achieved when olive oil was mixed with a 2%aqueous solution of β-CD and the resulting precipitate was treated with ethyl alcohol.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 18–21, January–February, 2005.     

Anaphaloside,a New Acyl Flavonoid Glycoside from the Flowers of Anaphalis Contorts Hooker

A new acyl flavonoid glycoside, anaphaloside, together with isoquercitrin and astragalin have been isolated from the flowers of Anaphalis contorta HOOKER . Their structures were elucidated on the basis of chemical and spectral evidence.     

Phenolic Compounds from Elsholtzia Bodinieri Van't

Seven phenolic compounds, including one new compound trans‐3,4,3′,5′‐tetrahydroxy‐4′‐methylstilbene 4‐O‐β‐D‐xylopyranosyl‐(1→6)‐β‐D‐glucopyranoside ( 1 ), together with six known compounds (+)‐hinokiol ( 2 ), 6‐hydroxy‐5,7‐dimethoxycoumarin ( 3 ), caffeic acid ( 4 ), vanillic acid ( 5 ), 4‐hydroxy‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 6 ) and 4‐allyl‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 7 ), were isolated from the root bark of Elsholtzia bodinieri Van't. Their structures were determined on the basis of spectroscopic and chemical evidence.     

An Efficient Synthesis of (±)-α-Spirovetivene and Related Compounds

A process for the synthesis of (±)-α-spirovetivene starting from I-oxo–2-carbethoxy-6, 10-dimethyl spiro[4.5]dec-6-ene(I)¹ is described. The oxo group of I was reduced by the process of Coates², and the resulting spiro ester (III) and spiro alcohol (IV) were transformed to (±)-α-spirovetivene by the process of Uijttewaal³ and by conventional methods.     

Cembranolides and Related Constituents from the Soft Coral Sarcophyton cinereum

In an attempt to explore the bioactive metabolites of the soft coral Sarcophyton cinereum, three new cembranolides, cinerenolides A–C (1–3), and 16 known compounds were isolated and identified from the EtOAc extract. The structures of the new cembranolides were elucidated on the basis of spectroscopic analysis, and the NOE analysis of cinerenolide A (1) was performed with the assistance of the calculated lowest-energy molecular model. The relative configuration of cinerenolide C (3) was determined by the quantum chemical NMR calculation, followed by applying DP4+ analysis. In addition, the cytotoxic assays disclosed that some compounds exhibited moderate to potent activities in the proliferation of P388, DLD-1, HuCCT-1, and CCD966SK cell lines.     

Polymer-Attached Thiazolium Salts-Catalyzed Addition of Aldehydes to α, β-Unsaturated Carbonyl Compounds

A homogeneous catalyst, 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride, for addition of aldehydes to activated double bond, was attached to 20% cross-linked polystyrene-divinylbenzene copolymer. The attached catalysts could be easily removed from the reaction mixture. Polymer-attached thiazolium salts in the presence of triethylamine are active catalysts for addition of aromatic and aliphatic aldehydes to α,β-unsaturated ketones to yield γ-diketones.     

Sesquiterpenoids and Their Glycosides from Gynura procumbens

Chemical investigation of the MeOH extract of the leaves of Gynura procumbens (Lour .) Merr . afforded one new sesquiterpenoid, muurol‐4‐ene‐1β,3β,10β‐triol ( 1 ), and two sesquiterpene glycosides, muurol‐4‐ene‐1β,3β,10β‐triol 3‐O‐β‐D ‐glucopyranoside ( 2 ) and muurol‐4‐ene‐1β,3β,15‐triol 3‐O‐β‐D ‐glucopyranoside ( 3 ), together with three known sesquiterpenoids. Their structures were elucidated on the basis of spectroscopic analyses and chemical methods.     

Sulfamic Acid as a Cost‐Effective and Recyclable Catalyst for β‐Amino Carbonyl Compounds Synthesis

Sulfamic acid was used as a catalyst in the synthesis of β‐amino carbonyl compounds from amines, acetophenone and aldehyde. The reaction was carried out at room temperature. High selectivity, mild reaction temperature, cost‐effective catalyst, simple product separation and catalyst recycle were notable achievements in the reaction. Another feature was that the reaction could be performed on a relatively larger scale to the model reaction (50 times), which also gave good yields. In particular, the first preparation of β, β'‐diamino diketone derivatives via the direct coupling of amines, acetophenone and isophthalic aldehyde promoted by sulfamic acid has been developed.     

Hepatitis C Virus NS3/4A Inhibition and Host Immunomodulation by Tannins from Terminalia chebula: A Structural Perspective

Terminalia chebula Retz. forms a key component of traditional folk medicine and is also reported to possess antihepatitis C virus (HCV) and immunomodulatory activities. However, information on the intermolecular interactions of phytochemicals from this plant with HCV and human proteins are yet to be established. Thus, by this current study, we investigated the HCV NS3/4A inhibitory and host immune-modulatory activity of phytocompounds from T. chebula through in silico strategies involving network pharmacology and structural bioinformatics techniques. To start with, the phytochemical dataset of T. chebula was curated from biological databases and the published literature. Further, the target ability of the phytocompounds was predicted using BindingDB for both HCV NS3/4A and other probable host targets involved in the immune system. Further, the identified targets were docked to the phytochemical dataset using AutoDock Vina executed through the POAP pipeline. The resultant docked complexes with significant binding energy were subjected to 50 ns molecular dynamics (MD) simulation in order to infer the stability of complex formation. During network pharmacology analysis, the gene set pathway enrichment of host targets was performed using the STRING and Reactome pathway databases. Further, the biological network among compounds, proteins, and pathways was constructed using Cytoscape 3.6.1. Furthermore, the druglikeness, side effects, and toxicity of the phytocompounds were also predicted using the MolSoft, ADVERpred, and PreADMET methods, respectively. Out of 41 selected compounds, 10 were predicted to target HCV NS3/4A and also to possess druglike and nontoxic properties. Among these 10 molecules, Chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose exhibited potent HCV NS3/4A inhibitory activity, as these scored a lowest binding energy (BE) of −8.6 kcal/mol and −7.7 kcal/mol with 11 and 20 intermolecular interactions with active site residues, respectively. These findings are highly comparable with Asunaprevir (known inhibitor of HCV NS3/4A), which scored a BE of −7.4 kcal/mol with 20 key intermolecular interactions. MD studies also strongly suggest that chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose as promising leads, as these molecules showed stable binding during 50 ns of production run. Further, the gene set enrichment and network analysis of 18 protein targets prioritized 10 compounds and were predicted to potentially modulate the host immune system, hemostasis, cytokine levels, interleukins signaling pathways, and platelet aggregation. On overall analysis, this present study predicts that tannins from T. chebula have a potential HCV NS3/4A inhibitory and host immune-modulatory activity. However, further experimental studies are required to confirm the efficacies.     

Maillard and Hydrolytic Reactions in Subcritical Water Extraction of Bioactive Compounds from Licorice

Nowadays, subcritical water extraction (SWE) techniques are extensively investigated worldwide, while the thermal reactions that inevitably occur under subcritical water conditions are rarely studied. In order to investigate the behaviors of the different reactions during SWE of bioactive compounds from licorice, the Maillard reaction process was accessed via their products and the hydrolytic reaction was analyzed according to the kinetic parameters. In addition, the contents of total phenolics and flavonoids in the extracts obtained at the different temperatures were determined and total antioxidant capacities were evaluated by HPLC-ABTS⁺. The results showed that flavonoids and phenolics from licorice as well as new compounds generated via the Maillard reaction contributed to the antioxidant activity of the extracts. The fluorescence, color and absorbance of the extracts showed that the degree of the Maillard reaction increased with the rise of the extraction temperature. The kinetics of extraction for glycyrrhizic acid showed that it was firstly extracted by diffusion, and then was hydrolyzed into glycyrrhetinic acid 3-O-mono-β-D-glucuronide and glycyrrhetinic acid following a first-order mechanism. These findings could provide deep insights into the SWE process and a new method for producing glycyrrhetinic acid 3-O-mono-β-D-glucuronide and glycyrrhetinic acid.     

Synthesis of Some New Fused/Spiroheterocyclic Compounds Incorporating Quinone Compounds

A series of fused and spiro pyrazolones, isoxazolines, pyrimidines, β‐lactams, and thiazolidinones incorporating 4‐amino‐2‐methyl‐5,10‐dioxo‐1,5,10,11‐tetrahydrobenz[g]quinoline 3‐carbonitrile 1 and 4‐amino‐2‐methyl‐5,6,11‐trioxo‐1,4,4a,5,6,11,12,12a‐octahydro‐1,12‐diazanaphthacene 3‐carbonitrile 2. 7,8a‐c, 15,16a‐c, 19,20a‐d, 21,22a‐d , have been synthesised by cyclocondensation addition reaction and cycloaddition reaction of hydrazines, hydroxylamine, urea, thiourea, monochloroacetyl chloride and mercaptoacetic acid with the synthesised 15,16a‐c and 17,18a‐c .     

Chemistry of 2-Amino-3-carbethoxythiophene and Related Compounds

This review describes the synthesis and reactions of 2-amino-3-carbethoxythiophenes as building blocks for the syntheses of poly functionalized heterocyclic compounds.     

Characterization of an Isozyme of β-Glucosidase from Sweet Almond

A sweet almond β-glucosidase (EC 3.2.1.21) isozyme was purified from commercial crude product. The process of purification consisted of a Protein-Pak Q anion exchange chromatography following by a Superdex 75 HR gel filtration separation. The purified enzyme is a monomeric glycoprotein with molecular weight of 58 kDa and pI=4.55 which is distinguished from reported isozymes. The enzyme has apH optimum in the range of 5.2-5.6 when p-nitrophenyl-β-D-glycopyranosides are used as substrate and is stable up to 50 °C at that pH range. The purified protein also exhibits profound β-galactosidase and σ-L-arabinosidase activity. The study of substrate specificity revealed that lacking of hydroxymethyl group at C-5 of glycosides resulted in higher affinity for substrate binding to enzyme, whereas the chemical step of hydrolysis (k_cst) was prevented significantly. The pH activity profile displayed a bell-shaped curve for all measured p-nitrophenyl-β-D-glycopyranosides with apparent pK₁ and pK₂ values of 4.4-4.7 and 6.2-6.4, respectively. This isozyme was strongly inhibited by δ-gluconolactone (K_i = 160 μM) and 4-phenylimidazole (K_i = 17.8 μM) reversibly at pH 6.2. Among the tested glycoses, the binding affinity of N-acetyl-β-D-glucosamine to the enzyme (K_l = 52 mM) was 6 times stronger than that of glucose and its epimers.