Phenolic derivatives from root bark of Schisandra sphenanthera / 中国中药杂志

This paper aimed to study the chemical constituents from the root bark of Schisandra sphenanthera. Silica, Sephadex LH-20 and RP-HPLC were used to separate and purify the 80% ethanol extract of S. sphenanthera. Eleven compounds were identified by ~1H-NMR, ~(13)C-NMR, ESI-MS, etc., which were 2-[2-hydroxy-5-(3-hydroxypropyl)-3-methoxyphenyl]-propane-1,3-diol(1), threo-7-methoxyguaiacylglycerol(2),4-O-(2-hydroxy-1-hydroxymethylethyl)-dihydroconiferylalcohol(3), morusin(4), sanggenol A(5), sanggenon I(6), sanggenon N(7), leachianone G(8),(+)-catechin(9), epicatechin(10), and 7,4'-dimethoxyisoflavone(11). Among them, compound 1 was a new compound, and compounds 2-9 were isolated from S. sphenanthera for the first time. Compounds 2-11 were subjected to cell viability assay, and the results revealed that compounds 4 and 5 had potential cytotoxicity, and compound 4 also had potential antiviral activity.

A new class of potent liver injury protective compounds: Structural elucidation, total synthesis and bioactivity study

A new class of potent liver injury protective compounds, phychetins A-D ( 1- 4) featuring an unique 6/6/5/6/5 pentacyclic framework, were isolated and structurally characterized from a Chinese medicinal plant Phyllanthus franchetianus. Compounds 2- 4 are three pairs of enantiomers that were initially obtained in a racemic manner, and were further separated by chiral HPLC preparation. Compounds 1- 4 were proposed to be originated biosynthetically from a coexisting lignan via an intramolecular Friedel-Crafts reaction as the key step. A bioinspired total synthesis strategy was thus designated, and allowed the effective syntheses of compounds 2- 4 in high yields. Some of compounds exhibited significant anti-inflammatory activities in vitro via suppressing the production of pro-inflammatory cytokine IL-1β. Notably, compound 4, the most active enantiomeric pair in vitro, displayed prominent potent protecting activity against liver injury at a low dose of 3 mg/kg in mice, which could serve as a promising lead for the development of acute liver injury therapeutic agent.

Four new dammarane-type triterpenoid saponins from Gynostemma longipes C.Y.Wu / 药学学报

Dammarane-type triterpenoid saponins are regarded as the main active constituents of Gynostemma longipes C.Y.Wu. By using MCI and silica gel column chromatography, as well as preparative HPLC, we isolated four new dammarane-type triterpenoid saponins from the polar saponin fraction of G. longipes C.Y.Wu. Their structures were determined by comprehensive analyses of NMR and MS data and identified as (20S)-3β,20,21-trihydroxydammar-19-oxo-24-ene-3-O-{[α-L-rhamnopyranosyl(1→2)]-[β-D-xylopyranosyl(1→3)]-α-L-arabinopyranosyl}-21-O-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside (1), (20S)-3β,20,21-trihydroxydammar-24-ene-19-oxo-3-O-[α-L-rhamnopyranosyl(1→2)]-[β-D-xylopyranosyl(1→3)]-α-L-arabinopyranosyl-21-O-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside (2), (20S)-3β,19,20,21-terahydroxydammar-24-ene-3-O-{[α-L-rhamnopyranosyl(1→2)]-[β-D-xylopyranosyl(1→3)]-α-L-arabinopyranosyl}-21-O-[β-D-glucopyranosyl(1→6)]-β-D-glucopyranoside (3), (20S)-3β,20,21-trihydroxydammar-24-ene-3-O-{[α-L-rhamnopyranosyl(1→2)]-[β-D-glucopyranosyl(1→3)]-β-D-glucopyranosyl}-21-O-[β-D-glucopyranosyl(1→6)]-β-D-glucopyranoside (4). Compounds 1-4 are new dammarane-type triterpenoid saponins which contain five glycosyl residues.

A novel dimeric diterpenoid alkaloid from the Tibetan medicinal plant Aconitum tanguticum (Maxim.) Stapf / 药学学报

Two dimeric diterpenoid alkaloids were isolated from the whole plant of Aconitum tanguticum (Maxim.) Stapf and their structures were elucidated by extensive analysis of 1D, 2D-NMR and HR-MS data. One is a new compound and named tanguticurine A (1), and the other is the known compound anthoroidine B (2); both were isolated from this plant for the first time. The antiviral activity of compounds 1 and 2 against HCV and EV71 were also evaluated. It was found that compound 1 had a good inhibitory effect on HCV and EV71 with EC50 values of 15.5 and 9.7 μmol·L-1, respectively, and showed low cytotoxicity. Therefore, compound 1 is a good antiviral lead compound and deserves further study.

Alkaloid constituents from the fruits of Flueggea virosa / 中国天然药物

Three new indole alkaloids, flueindolines A-C (1-3), along with nine known alkaloids (4-12), were isolated from the fruits of Flueggea virosa (Roxb. ex Willd.) Voigt. Compounds 1 and 2 are two new fused tricyclic indole alkaloids possessing an unusual pyrido[1, 2-a]indole framework, and 3 presents a rare spiro (pyrrolizidinyl-oxindole) backbone. Their structures with absolute configurations were elucidated by means of comprehensive spectroscopic analysis, chemical calculation, as well as X-ray crystallography. Chiral resolution and absolute configuration determination of the known compounds 4, 10, and 11 were reported for the first time. The hypothetical biogenetical pathways of 1-3 were herein also proposed.

Anti-Acetylcholinesterase Compounds Isolated from the Leaves of Kigelia africana (LAM) Benth (Bignoniaceae)

Acetylcholinesterase (AChE) is an enzyme that is involved in the breakdown of some neurotransmitters. Its inhibition is one of the treatment strategies employed in the management Alzheimer diseases. Flavonoids isolated from the leaves of Kigelia africana were investigated for their comparative AChE inhibition. The extract of the leaves was subjected to vacuum liquid chromatography (VLC) to obtain four fractions using n-hexane (n-hex, 100%), n-hexane/dichloromethane (hex/DCM, 1:1), dichloromethane/ethyl acetate (DCM/EtOAc, 1:1) and ethyl acetate/methanol (EtOAc/MeOH, 1:1). The four fractions were subjected to AChE inhibitory study with DCM/EtOAc (1:1) fraction showing the highest inhibitory activity. Three flavonoids were isolated from this fraction and their structures were elucidated and characterised using 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) techniques. Their spectroscopic data compared well with literature. The compounds demonstrated considerable inhibition of AChE activity with luteolin (1), rutin (2) and quercetin (3) that showed IC50 of 945.0, 282.1, 254.8 μg/ml respectively as against the IC50 of 38.93 μg/ml for rivastigmine, a well-known cholinesterase inhibitor. Compound 3 showed 17.89 ± 0.57 and 7.70 ± 0.64 μ/l/mg protein at 200 and 400 μg/ml respectively, for AChE activity as against 10.37 ± 0.99 and 6.24 ± 1.24 μ/l/mg protein showed by rivastigmine at 200 and 400 μg/ml respectively. This study showed that the constituents responsible for the AChE inhibition in the crude extract as reported by Falode et al., 2017 resided in the DCM/EtOAc (1:1) fraction. The structure-activity relationship of the flavonoids revolves around substitution in position 3 of the compounds.

Isolation and Identification of Chemical Constituents from Rhizomes of Dendropanax proteus / 中国实验方剂学杂志

The chemical constituents from 95% ethanol extract of Dendropanax proteus rhizomes and their anti-inflammatory activities were investigated. These compounds in 95% ethanol extract of D. proteus rhizomes were isolated and purified by silica gel column chromatography, medium-pressure liquid chromatography, preparative liquid chromatography, etc. Their structures were elucidated based on the spectral data and physicochemical properties. All the compounds were tested for their ability to inhibit lipopolysaccharide (LPS) induced nitric oxide production in the murine microglia BV2 cell line. Nine compounds were isolated from the ethyl acetate fraction of 95% ethanol extract of D. proteus rhizomes, and identified as (-)-syringaresinol (1), (+)-(7S,8S)-1',4-dihydroxy-3,3',5'-trimethoxy-7',8,9'-trinor-8,4'-oxyneoligna-7,9-diol (2), erythro-guaiacylglycerol-β-O-4'-coniferyl ether (3), threo-guaiacylglycerol-β-O-4'-coniferyl ether (4), coniferyl alcohol (5), 7-O-ethylguaiacylglycerol (6), vanillin (7), syringaldehyde (8), and excoecanol B (9). Compounds 2 and 4 showed neuritis inhibitory activity against microglial inflammation factor, their half inhibitory concentrations (IC50) were 5.85, 7.29 μmol ·L-1, respectively. Compounds 1-6,8-9 are isolated from this plant for the first time, compounds 2 and 4 exhibit the potent inhibitory activity.

Isolation and Structural Elucidation of Chemical Constituents of Corydalis Rhizoma / 中国实验方剂学杂志

Objective: In order to clarify the characteristic chemical constituents and furnish applicable information to the basic research and quality control research related to the chemistry of traditional Chinese medicines for Corydalis Rhizoma,this paper investigated the chemical constituents of Corydalis Rhizoma extensively. Method: The dried-up and pulverized plant materials were extracted using 95% EtOH as solvent,the EtOH extract was fractionated using different solvents to afford the EtOAc-soluble and n-BuOH-soluble portion,respectively,among others. These two portions were subjected to procedures of isolation and purification on silica gel or ODS column chromatographies to afford monomers. 1D and 2D NMR and MS methods,along with comparison with the data of literatures,were used to identify the structures. Result: Twelve compounds,all belonging to alkaloids,were isolated and identified as d-corydaline(1),tetrahydrocoptisine(2),tetrahydropalmatine(3),tetrahydrocolumbamine(4),corybulbine(5),tetrahydrojatrorrhizine(6),dehydrocorydaline(7),dehydroglaucine(8),8-oxodihydrocoptisine(9),protopine(10),taxilamine(11),and pontevedrine(12). Of these compounds,the structure of 12 was a revised structure which was assigned by combined examinations of their 1D and 2D NMR spectra and MS data. Conclusion: Compounds 6 and 11 were reported from Corydalis Rhizoma for the first time. The structure of pontevedrine was verified as 1,2,9,10-tetramethoxy-6-methyl-4H-dibenzo[de,g]quinoline-4,5(6H)-dione.

Xylaroisopimaranin A, a New Isopimarane Derivative from an Endophytic Fungus Xylaralyce sp

Five secondary metabolites, including a new isopimarane derivative xylaroisopimaranin A (1), were isolated from the endophytic fungus Xylaralyce sp. (HM-1), and their structures were elucidated by 1D, 2D NMR, MS and CD spectra. Their bioactivities were performed to antibacterial, Hep G2 cells cytotoxicity and brine shrimp inhibition. The biological evaluation results showed that the xylaroisopimaranin A (1), xylabisboein B (2), griseofulvin (3) , 5-methylmellein (4) and mellein-5-carboxlic acid (5) displayed no significant Hep G2 cells cytotoxicity and antibacterial acitivity, but they inhibited the brine shrimp with IC₅₀ from 0.5 to 25 µmol/mL.

Chemical Constituents from the Aerial Parts of Paris polyphylla var. chinensis / 中国药学杂志

OBJECTIVE: To study the chemical constituents from the aerial parts of Paris polyphylla var. chinensis. METHODS: The compounds were isolated and purified from the 75% ethanol extract by chromatography on HPD100 macroporous resin, silica gel, and Sephadex LH-20 as well as semi-preparative HPLC. Their structures were elucidated on the basis of spectral data. RESULTS: Eleven compounds were isolated and identified as corchionoside C (1), β-ecdysterone (2), coronatasterone (3), kaempferol-3-O-β-D-galactopyranoside (4), astragalin (5), isorhamnetin-3-O-β-D-glucopyranoside (6), kaempferol-3-O-β-D-glucopyranosyl-(l→2)-β-D-galactopyranoside(7), isorhamnetin-3-O-β-D-glucopyranosyl-(l→2)-β-D-galactopyranoside (8), kaempferol-3-O-β-D-glucopyranosyl-(l→2)-β-D-glucopyranoside (9), isorhamnetin-3-O-β-D-galactopyranosyl-(l→6)-β-D-glucopyranoside (10), and isorhamnetin-3-O-β-D-gentiobioside (11). CONCLUSION: Compounds 1 and 3-11 are isolated from this plant for the first time and compounds 1, 3-5 and 8-10 are isolated from Paris plants for the first time.

Chemical constituents from the n-butanol portions of the fruits of Eucalyptus globulus / 中国药科大学学报

@#Phytochemical studies on the fruits of Eucalyptus globulus led to the isolation of twelve compounds. The structures of these compounds were elucidated as: ellagic acid(1), 3-O-methylellagic acid 4′-O-α-rhamnopyranoside(2), valoneic acid dilactone(3), isobiflorin(4), biflorin(5), 8-β-C-glucopyranosyl-5, 7-dihydroxy-2-isobutylchromone(6), 8-β-C-glucopyranosyl-5, 7-dihydroxy-2-isopropylchromone(7), quercetin 3-O-β-D-glucopyranoside(8), quercetin 3-O-β-D-glucuronide-6″-methyl ester(9), (+)-lyoniresin-4-yl β-D-glucopyranoside(10), cypellocarpins A(11), and eucaglobulin 1(12), by means of spectroscopic analyses(ESI-MS, 1H NMR and 13C NMR). Compounds 3-10 were isolated from this plant for the first time.

Chinoketides A and B, Two New Antimicrobial Polyketides from the Endophytes of Distylium chinense with the “Black-Box” Co-culture Method

Two new polyketides, chinoketides A and B (1 – 2) with a known compound xylarphthalide A (3), were isolated from the solid medium of the endophytes from the leaves of the relic plant Distylium chinense with the “black-box” co-culture method, and the structures of two new compounds were elucidated by NMR, MS and CD spectra. And the absolute configurations of chinoketides A (1) and B (2) were determined as 2R,3R,8S and 5R,6S by calculating their ECD spectra to compare with the experimental CD spectra. Finally, the antimicrobial activities were evaluated to Erwinia carotovora sub sp. Carotovora (Jones) Bersey et al, and the results showed that compounds 1 – 3 displayed the antimicrobial activities with MIC value at 20.5, 30.4 and 10.2 µg/mL.

Chemical constituents from roots of Isatis indigotica / 中国中药杂志

Nineteen compounds were isolated from the roots of Isatis indigotica through silica gel, Sephadex LH-20, ODS and pre-HPLC chromatography technique. Their structures were elucidated by the MS and NMR spectra as 7-hydroxydeoxyvasicinone (1), (1H-indol-3-yl) oxoacetamide (2), 1-methoxy-1H-indole-3-acetonitrile (3), arvelexin (4), 1H-indole-3-acetonitrile (5), 1H-indole-3-aldehyde (6), 1H-indole-3-acetic acid (7), 2,3-dihydro-4-hydroxy-2-oxo-indole-3-acetonitrile (8), deoxyvasicinone (9), indigotiisocoumarin A (10), cycloanthranilylproline (11), quinazoline-2,4(1H,3H)-diones (12), indirubin(13), (+)-pinoresinol (14), (+)-epipinoresinol (15), burselignan (16), (+)-isolariciresinol (17),vanillic acid (18) and 5-hydroxymaltol (19). Among them, compound 1 is a new natural product, and compound 2, 14, 15, 18 and 19 were isolated from the title plant for the first time.

Historical story on natural medicine chemistry: Application of UV, IR, MS, and NMR spectra in structure elucidation of natural products / 中草药

The study on natural product chemistry plays an important role in drug development, and the structure elucidation is one of the vital tasks in the natural product chemistry research. This paper summarized the application of UV, IR, MS, and NMR spectra in the structure elucidation of natural products with 123 papers cited. This article is one of the series of historical stories on natural product chemistry published in this journal, which are reviewed and summerized. The developing future is looked forward.

Lipophilic constituents from the stem bark of Toona sinensis / 中国药科大学学报

@#Ten compounds were isolated from the 95% ethanol extract of the stem bark of Toona sinensis by silica gel, ODS Sephadex LH-20 column chromatographies and preparation TLC methods. Their structures were elucidated by spectroscopic methods and chemical properties as betulinic acid(1), stigmastane-3, 6-dione(2), stigmast-4-en-3-one(3), 7β-hydroxysitosterol(4), 6-hydroxystigmast-4-en-3-one(5), stigmast-4-ene-3β, 6β-diol(6), ergosterol peroxide(7), 7-methoxy-2-(3, 4-methylenedioxyphenyl)benzofuran-5-carboxylate(8), canthin-6-one(9), and α-acetylamino-phenylpropyl α-benzoylamino phenylpropionate(10). All compounds were isolated from T. sinensis for the first time.

Compounds from a jellyfish-derived fungus Aspergillus fumigates

Six compounds were isolated from the secondary metabolites of the jellyfish-derived fungus Aspergillus fumigates, whose structures were identified by chemical methods and spectroscopic analysis as pseurotin F1 (1), azaspirofurans B (2), (22E, 24R)-24-methyl-5α-cholesta-7,22-diene-3β,5,6β-triol (3), 5α,8α-epidioxyergosta-6,22-dien-3β-o1 (4), cyclo-(L-Pro-L-Tyr) (5), fumitremorgin C (6). The compounds 1 - 5 were isolated from the fungus Aspergillus fumigates for the first time. The isolated compounds (1 - 6) were evaluated for antibiotic activity and cytotoxicity against six bacterial strains and ten human tumor cell lines, respectively.

Several stereogenic problems regarding structural elucidation of marine natural products / 国际药学研究杂志

During the structural elucidation of natural products, one of the key steps is attributed to the solution of configuration including chiral carbons, axial and planar asymmetry. Stereogenic assignment is an essential work involved in natural product chemistry, while identification of stereogenic centers may be helpful to recognize the structure related to target function. Modern spectroscopic technology provided a reliable tool for the configurational assignment. In this paper, we intend to summarize part of our work regarding the application of extensive spectroscopic methods for the determination of the absolute configurations of marine-derived natural products.

Isolation, purification and structural elucidation of polysaccharide from Saccharum Alhagi / 中国药学杂志

OBJECTIVE: To isolate and purify the polysaccharide from Saccharum Alhagi, and to clarify its chemical structure. METHODS: Water extracting-alcohol precipitating method was applied to extract polysaccharide from Saccharum Alhagi. Macro-porous adsorption resin chromatography, DEAE cellulose chromatography and Sephadex gel chromatography were applied to fractionalize and purify the polysaccharide. The homogeneity and molecular weight of the polysaccharide were determined by gel filtration. The monosaccharide composition of the polysaccharide was identified by gas chromatography (GC). Partial acid hydrolysis, periodate oxidation, smith degradation and NMR were used to analyze the chemical structure of the polysaccharide. RESULTS: Polysaccharide fraction AP1-1 was got from Saccharum Alhagi. The analysis results show that APl-1was a homogeneous polysaccharide and its molecular weight was 99.7 × 10. AP1-1 was composed of mannose, glucose, galactose with molar ratio of 1.10:2.19:4.32.The main chain of AP1-1was mainly made up of →4)-β-D-GalpA-(1→, →4)-β-D-Galp-(1→ and →4, 6)-α-D-Glcp-(1 →. The side chain was composed of →6)-α-D-Glcp and 2-OCH3-α-D-Man. CONCLUSION: Saccharum Alhagi polysaccharide AP1-1 is a complicated hetero-polysaccharide with multi-branches.

Research on 5α, 8α-epidioxy sterols from the south china sea gorgonian menella kanisa / 第二军医大学学报

Objective To investigate the chemical components of gorgonian Menella kanisa collected from the South China Sea. Methods The Et2O extract of gorgonian Menella kanisa was purified by repeated column chromatography on silica gel, Sephadex LH-20, and reversed-phase high-performance liquid chromatography (RP-HPLC). The structures of the obtained compoundswere determined on the basis of spectroscopic analysis and compared with the reported data. Results and Conclusion Five 5α, 8α-epidioxy sterolswere isolated from gorgonian Menella kanisa collected from the South China Sea, and their structures were determined as: 5α, 8α-epidioxy-cholest-6-en-3/β-ol (1), (22E)-5α, 8α-epidioxy-cholesta-6, 22-dien-3/β-ol (2), (22E, 2iR)-5α, 8α-epidioxy-24-methyl-cholesta-6, 22-dien-β-ol (3), 5α, 8α-epidioxy-24-methyl-cholesta-6, 24 (28)-dien-β-ol (4), (24E)-5α, 8α-epidioxy-24-ethyl-cholesta-6, 24(28)-dien-β-ol (5). All the five epidioxy sterols have been separated from the title Menella kanisa for the first time.

5α, 8α-epidioxy sterol components in gorgonian Muriceopsis flavida collected from the South China sea / 第二军医大学学报

Objective: To investigate the bioactive chemical constituents of gorgonian Muriceopsis flavida collected from the South China Sea. Methods: The Et2O extract of the sample was purified by repeated column chromatographies on silica gel, Sephadex LH-20, and RP-HPLC. The structures of the obtained compounds were elucidated based on detailed spectroscopic analysis using mass spectrometry (MS) and nuclear magnetic resonance (NMR). The in viteo antimicrobial activities of the identified compounds were assessed by an agar diffusion test. Results: Five 5α, 8α-epidioxy sterols were isolated from the Et2O extract (1-5), and their structures were determined as: (22E, 24S)-5α, 8α-epidioxy-24-methyl-cholesta-6, 22-dien-3β-ol (1), (22E,24R)-5α, 8α-epidioxy-24-methyl-cholesta-6, 22-dien-3β-ol (2), (24R)-5α, 8α-epdioxr24-ethyl-cholesta-6-en-3β-ol (3), (22E)-5α, 8α-epidioxy-choles--6, 22-dien-3β-ol (4), and 5α, 8α-epidioxy-choles--6-en-3β-ol (5). These compounds showed different degrees of antimicrobial activities in bioassay in vitro. Conclusion: The five compounds have been identified for the first time from the gorgonian Muriceopsis flavida. Compounds 2 shows a strong anti-algae effect and is worth further studying.