Chemical constituents from ethyl acetate fraction of Swertia davidii / 中草药

Objective: To study the chemical constituents from Swertia davidii. Methods: The chemical constituents of the ethyl acetate fraction from the whole plants of S. davidii (Gentianaceae) were investigated by various chromatographic methods including silica gel, ODS, semi-preparative HPLC and so on. Their structures were identified on the basis of NMR spectral data analysis and comparisons with the data reported in literatures. Results: Seventeen known compounds were separated and purified from the ethyl acetate fraction of this plant, which were identified as gentiocrucine (1), gentiocrucine A (2), gentiocrucine B (3), junipediol A (4), 1-hydroxy-3,4,7,8-tetramethoxyxanthone (5), 1,7,8-trihydroxy-3-methoxyxanthone (6), 1,8-dihydroxy-3,4,7-trimethoxyxanthone (7), 1,5,8-trihydroxy-3-methoxyxanthone (8), swertianolin (9), deacetylcentapicrin (10), amarogentin (11), amaroswerin (12), swertiamarin (13), gentiopicroside (14), oleanolic acid (15), daucosterol (16), and β-sitosterol (17). Conclusion: Compounds 1-6, 10, 12, 16, and 17 are isolated from S. davidii for the first time.

Binding interaction of harpagoside and bovine serum albumin: spectroscopic methodologies and molecular docking / 中国中药杂志

Scrophularia ningpoensis has exhibited a variety of biological activities and been used as a pharmaceutical product for the treatment of inflammatory ailment, rheumatoid arthritis, osteoarthritis and so on. Harpagoside (HAR) is considerer as a main bioactive compound in this plant. Serum albumin has important physiological roles in transportation, distribution and metabolism of many endogenous and exogenous substances in body. It is of great significance to study the interaction mechanism between HAR and bovine serum albumin (BSA). The mechanism of interaction between HAR and BSA was investigated using 2D and 3D fluorescence, synchronous florescence, ultraviolet spectroscopy and molecular docking. According to the analysis of fluorescence spectra, HAR could strongly quench the fluorescence of BSA, and the static quenching process indicated that the decrease in the quenching constant was observed with the increase in temperature. The magnitude of binding constants (KA) was more than 1×10⁵ L·mol⁻¹, and the number of binding sites(n) was approximate to 1. The thermodynamic parameters were calculated through analysis of fluorescence data with Stern-Volmer and Van't Hoff equation. The calculated enthalpy change (ΔH) and entropy change (ΔS) implied that the main interaction forces of HAR with BSA were the bonding interaction between van der Waals forces and hydrogen. The negative values of energy (ΔG) demonstrated that the binding of HAR with BSA was a spontaneous and exothermic process. The binding distance(r) between HAR and BSA was calculated to be about 2.80 nm based on the theory of Frster's non-radiation energy transfer, which indicated that energy is likely to be transfer from BSA to HAR. Both synchronous and 3D florescence spectroscopy clearly revealed that the microenvironment and conformation of BSA changed during the binding interaction between HAR and BSA. The molecular docking analysis revealed HAR is more inclined to BSA and human serum albumin (HSA) in subdomain ⅡA (Sudlow's site I). This study will provide valuable information for understanding the action mechanism of HAR.

Chemical constituents of Swertia delavayi and their anti-hepatitis B virus activity / 中国中药杂志

Fifteen known compounds were isolated from Swertia delavayi by silica gel, Sephadex LH-20 and Rp-18 column chromatographies. Based on extensive spectroscopic analysis (MS, 1H, 13C-NMR), their structures were identified aserythrocentaurin (1), erythrocentaurindimethylacetal (2), sweroside (3), swertiamarin (4), gentiopicroside (5), swertiakoside A (6), 2'-O-acetylswertiamarin (7), 4'-O-[(Z) -coumaroyl] swertiamarin (8), 1,5,8-trihydroxy-3-methoxyxanthone (9), 8-O-β-D-glucopyranosyl-1-hydroxy-2,3, 5-trimethoxyxanthone (10), 8-O-[β-D-xyl- opyranosyl-(1 --> 6)-β-D-glucopyranosyl]-7,8-dihydroxy-3-methoxyxanthone (11), isovitexin (12), β-sitosterol (13), daucosterol (14), and oleanolic acid (15). Among them, ten ones (14, 7-11, 13) were obtained from S. delavayi for the first time. The isolates were evaluated for their anti-HBV activities in HepG 2. 2. 15 cell line in vitro. The results showed that compound 1, 2, 6, 7, 9 and 12 exhibited significant inhibitory activity on HBV DNA replication with IC50 values from 0.05 to 1.46 mmol x L(-1).

Chemical constituents of Swertia patens / 中国中药杂志

Chemical constituents of Swertia patens. The whole plant of air-dried Swertia patens was extracted with 90% EtOH. The water extract was suspended in H₂O and extracted with petroleum ether, EtOAc and n-BuOH, successively. The compounds were isola- ted and purified by column chromatography from the EtOAc fraction, and identified based on spectral analyses (MS, ¹H-NMR, ¹³C- NMR). Eighteen compounds were isolated and elucidated as 3, 4-dihydro-1H,6H,8H-naptho [1,2-c:4,5-c', d'dipyrano-1, 8-dione (1), angelone (2), gentiogenal (3), erythricin (4), erythrocentaurin (5), gentianine (6), swertiakoside B (7), swertiamarin (8), 2'-O-actylswertiamarin (9), amarogentin (10), 1, 3, 5-trihydroxyxanthone (11), 1, 3-dihydroxy-5-methoxyxanthone (12), 1-hydroxy- 2, 3, 5-trimethoxyxanthone (13), gentiocrucine (14), 3-hydroxyphenylketone (15), n-hexacosyl ester 4-hydroxy-trans-cinnamate (16), n-hexacosyl ester 4-hydroxy-cis-cinnamate (17), and cholest-4-en-3-one (18). Compounds 1-7, 9-18 were obtained from S. patens for the first time.

Chemical constituents of Swertia kouitchensis Franch / 中国中药杂志

This study is to investigate the chemical constituents of Swertia kouitchensis. The whole plants of air-dried Swertia kouitchensis was extracted with 90% EtOH. The water extract was suspended in H2O and extracted with petroleum ether, EtOAc and n-BuOH, successively. The compounds were isolated and purified by column chromatography from the EtOAc fraction, and their structures were identified based on spectral analyses (MS, 1H-NMR, 13C-NMR). Twenty-eight compounds were obtained, and characterized as erythrocentaurin (1), erythrocentaurin dimethylacetal (2), swertiamarin (3), vogeloside (4), 2'-O- actylswertiamarin (5), swertianoside D (6), gentiocrucines A-B (7-8), gentiocrucine (9), 1-hydroxy-3, 7, 8-trimethoxyxanthone (10), 1-hydroxy-3, 5, 6-trimethoxyxanthone (11), 3-epitaraxerol (12), erythrodiol 3-O-palmitate (13), (+) -syringaresinol (14), caffeic acid (15), trans-coniferyl aldehyde (16), trans-coniferyl alcohol (17), 3, 4-dihydroxybenzoic acid (18), 4-hydroxy-3-methoxybenzoic acid (19), 3, 4-dihydroxybenzoic aldehyde (20), 2, 3-dihydroxybenzoic acid (21), 4-hydroxybenzoic acid (22), 3-acetoxybenzoic acid (23), 3-hydroxybenzoic acid (24), 3-hydroxybenzoic alcohol (25), nicotinic acid (26), 2-furoic acid (27), and uracil (28). Compounds 1-4, 6-28 were obtained from S. kouitchensis for the first time.

Chemical constituents of Swertia angustifolia / 中国中药杂志

This present work is to study the chemical constituents of Swertia angustifolia. The whole plants of air-dried Swertia angustifolia was extracted with 90% EtOH. The water extract was suspended in H2O and extracted with petroleum ether, EtOAc and nBuOH, successively. The compounds were isolated and purified by column chromatography from the EtOAc fraction, and identified based on spectral analyses (MS, 1H-NMR, 13C-NMR). Fourteen compounds were isolated and characterized as 1, 8-dihydroxy-3, 7-dimethoxyxanthone (1), 1, 8-dihydroxy-3, 5, 7-trimethoxyxanthone (2), 7-hydroxy-3, 8-dimethoxyxanthone-1-O-β-D-glucopyranoside (3), 8-0-[β-D-xylopyranosyl-(1-6) -β-D-glucopyranosyl] -1, 7-dihydroxy-3-methoxyxanthone (4), (+) -syringaresinol (5), ferulic acid (6), trans-coniferyl aldehyde (7), sinapaldehyde (8), trans-coniferyl alcohol (9), 3, 4-dihydroxybenzoic acid (10), 2-hydroxybenzoic acid (11), isophthalic acid (12), 2-furoic acid (13), and 2-methyl-4(3H)-quinazolinone(14). Compounds 2-14 were obtained from this plant for the first time.

Chemical structure of capsicuoside A from fruits of Capsicum annuum / 中国中药杂志

Five compounds were isolated from Capsicum annuum by means of various chromatographic techniques (silica gel, Sephadex LH-20, MCI GEL CHP-20P and HPLC), and their structures were determined as luteolin-7-O-[2"-O-(5"-O-sinapoyl)-beta-D-apiofuranosyl]-beta-D-glucopyranoside (1), uridine (2), adenosine (3), 7-hydroxy-6-methoxy cinnamic acid ethyl ester (4) and 7-hydroxy cinnamic acid ethyl ester (5) by extensive spectroscopic analyses (UV, IR, MS, 1D- and 2D-NMR). Among them, compound 1 is a new flavone glycoside named as capsicuoside A, and cmpounds 2-5 are isolated for the first time from the fruits of C. annuum.