Inhibition of angiotensin-I-converting enzyme by tetrahydroxyxanthones isolated from Tripterospermum lanceolatum.

Five tetrahydroxyxanthones, 3,4,6,7-tetrahydroxyxanthone [1], 1,3,5,6-tetrahydroxyxanthone [2], 3,4,5,6-tetrahydroxyxanthone [3], 1,3,6,7-tetrahydroxyxanthone [4], and 2,3,6,7-tetrahydroxyxanthone [5] isolated from Tripterospermum lanceolatum inhibited angiotensin-I-converting-enzyme activity in a dose-dependent manner. The mode of inhibition of the tetrahydroxyxanthones (THXs) was found to be competitive inhibition. When the tetrahydroxy groups of THXs were blocked with acetyl groups, the angiotensin-I-converting-enzyme inhibitory activity was abolished, suggesting that the tetrahydroxy groups are indispensible for the inhibitory activity.     

柘木茎的化学成分研究

目的:研究柘木茎的化学成分.方法:采用硅胶柱色谱和Sephadex LH-20凝胶柱色谱等色谱方法进行分离纯化,并根据NMR,MS等波谱方法和理化性质鉴定其化学结构.结果:从其醇提物中分离得到13个化合物,分别为(3β,13α,14β,17α)-7,24-二烯-3-乙酰羊毛甾醇(1),粘霉烯醇(2),蒲公英萜酮(3),槲皮素(4),山奈酚(5),异鼠李素(6),香豌豆酚(7),3'.甲氧基奥洛波尔(8),花旗松素(9),柑桔素(10),草大戟素(11),1,3,6,7-四羟基口山酮(12),5,7-二羟基色原酮(13).结论:化合物1-3,6,13为首次从柘属中分离得到,化合物12为首次从本植物中分离得到,且首次报道从本属植物中分离得到三萜类成分.     

长梗喉毛花口山酮类化学成分的研究

目的:研究长梗喉毛花醋酸乙酯部位中(口山)酮类化学成分.方法:应用多种色谱技术进行分离纯化,根据化合物的理化性质和波谱数据鉴定化合物的结构.结果:从长梗喉毛花全草70%乙醇提取物的醋酸乙酯萃取部位对DL-半乳糖胺所致的肝损伤具有保肝作用的活性部位中分离得到9个(口山)酮类化合物,分别鉴定为1,8-二羟基-2,6-二甲氧基(口山)酮(1),8-羟基-1,2,6-三甲氧基(口山)酮(2),1,6,8-三羟基-2-甲氧基(口山)酮(3),1,8-二羟基-3,5-二甲氧基(口山)酮(4),1-羟基-3,5,8-三甲氧基(口山)酮(5),1-羟基-3,7-二甲氧基(口山)酮(6),1,2,6,8-四羟基(口山)酮(7),1,3,7-三羟基-4-甲氧基(口山)酮(8),6,8-二羟基-1,2-二甲氧基(口山)酮(9).结论:化合物6～9为首次从该属植物中分离得到.     

青叶胆化学成分研究

目的：对龙胆科獐牙菜属植物青叶胆Swertia mileensis的干燥全草进行化学成分研究。方法：青叶胆的干燥全草用50%乙醇提取，依次用石油醚、氯仿、正丁醇萃取，对氯仿部分采用各种柱色谱进行分离纯化，通过波谱数据分析进行结构鉴定。结果：从氯仿部分分离鉴定了12个化合物，其中8个酮，1，5，8-三羟基-3-甲氧基酮(1)，1-羟基-2，3，5，7- 四甲氧基酮(2)，1-羟基-3，5，8-三甲氧基酮(3)，1-羟基-2，3，4，6-四甲氧基酮(4)，1-羟基-2，3，4，7-四甲氧基酮(5)，1，8-二羟基3，5-二甲氧基酮(6)，1，7-二羟基-3，8-二甲氧基酮(7)，1，3，5，8-四羟基酮(8)，1个木脂素，balanophonin(9)，3个三萜，齐墩果酸(10)，山楂酸(11)，苏门树脂酸(12)。结论：化合物1，3，7～9，11，12为首次从青叶胆中分离得到。     

构棘化学成分研究

目的：研究桑科柘属植物构棘Cudrania cochinchinensis干燥根的化学成分。方法：利用各种硅胶、聚酰胺柱色谱技术进行分离纯化,根据NMR,MS等波谱分析和理化性质鉴定其化学结构。结果：从构棘95%乙醇提取物的醋酸乙酯部分分离得到6个黄酮类化合物。分别为3,5,7,4′-四羟基黄酮-7-O-(6″-乙酰基)-葡萄糖苷(1),3,5,7,4′-四羟基黄酮-7-O-葡萄糖苷(2),6-异戊烯基-5,7,2′,4′-四羟基二氢黄酮(3),6-异戊烯基-5,7,4′-三羟基异黄酮(4),1,3,5,6-四羟基酮(5),2,4,3′,5′-四羟基二苯乙烯(6)。结论：化合物1为首次从本属植物中分得,4,5为首次从本植物中分得。     

贵州獐牙菜化学成分研究

从贵州獐牙菜Swerlia kauitchensis中分离鉴定出齐墩果酸、胡萝卜苷、1,7-二羟基-3,8-二甲氧基酮等10个化合物.均为首次从该植物中分得.     

毛萼獐牙菜化学成分的研究

目的:对龙胆科Gentianaceae獐牙菜属植物毛萼獐牙菜Swertia hispidicalyx Burk.的干燥全草进行化学成分研究.方法:采用各种柱色谱进行分离纯化,通过波谱数据分析( MS,1H-,13C-NMR)进行结构鉴定.结果:从乙酸乙酯萃取部分分离鉴定了11个化合物,其中2个口山酮,2个裂环烯醚萜,2个三萜,2个甾体,以及3个其他类化合物,它们分别鉴定为1,3,5,8-四羟基口山酮(1,3,5,8-tetrahydroxyxanthone,1),1,5,8-三羟基-3-甲氧基口山酮(1,5,8-trihydroxy-3-methoxyxanthone,2),龙胆内酯( gentiolactone,3),獐牙菜苦苷(swertiamarin,4),3,4-dihydro-1H,6H,8H-naphtho[1,2-c:4,5-c',d']dipyrano-1,8-dione(5),(+)-丁香脂素[(+)-syringaresinol,6)],松柏醛(trans-coniferyl aldehyde,7),山楂酸(maslinic acid,8),齐墩果酸(oleanolic acid,9),胡萝卜苷(daucosterol,10),β-谷甾醇(β-sitosterol,11).结论:化合物1～11均为首次从毛萼獐牙菜中分离得到.     

元宝草化学成分的分离与鉴定

目的对元宝草进行化学成分研究。方法采用硅胶柱色谱、Sephadex LH-20柱色谱、重结晶等方法进行分离纯化,根据理化性质和波谱数据进行结构鉴定。结果分离得到9个化合物,分别鉴定为1,7-二羟基酮①、1,3,5,6-四羟基酮②、5,7,4’-三羟基-黄酮醇③、5,7,3’,4’-四羟基-黄酮醇④、金丝桃苷⑤、山萘酚-3-0-葡萄糖苷⑥、对羟基苯甲酸⑦、3,4-二羟基苯甲酸⑧、白桦脂酸⑨。结论化合物7,9为首次从该植物中分离得到。     

Antiproliferative triterpene saponins from Trevesia palmata

During the course of a study of plants of the family Araliaceae, antiproliferative activity was demonstrated by the crude saponin fraction of Trevesia palmata. After chromatographic purification, six new bisdesmosidic saponins (1-6), along with two known triterpenoid saponins, (7 and 8), were isolated. The structures of 1-6 were determined by (1)H-(1)H correlation spectroscopy (COSY-DQF, 1D TOCSY, 2D HOHAHA, 1D ROESY) and (1)H-(13)C (HSQC, HMBC) spectroscopy. The antiproliferative activity of compounds 1-8 and of their prosapogenins (2a-7a) prepared by alkaline hydrolysis, was evaluated using three continuous culture cell lines.     

Phenolic compounds from the roots of Jordanian viper's grass, Scorzonera judaica

Nine new phenolic compounds, 3S-hydrangenol 40-O-R-L-rhamnopyranoysl-(1-->3)-β-D-glucopyranoside (1), thunberginol F 7-O-β-D-glucopyranoside (2), 2-hydroxy-6-[2-(4-hydroxyphenyl)-2-oxo-ethyl]benzoic acid (3), 2-hydroxy-6-[2-(3,4-dihydroxyphenyl)-2-oxo-ethyl]benzoic acid (4), 2-hydroxy-6-[2-(3,4-dihydroxyphenyl-5-methoxy)-2-oxoethyl]benzoic acid (5), hydrangeic acid 40-O-β-D-glucopyranoside (6), E-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)dihydrofuran-2-one (7), Z-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)-2(3H)-furanone (8), and 4-[β-D-glucopyranosyl)hydroxy]-pinoresinol (9), and nine known compounds were isolated from the roots of Scorzonera judaica. Structures of 1-9 were elucidated by mass spectrometry, extensive 1D and 2D NMR spectroscopy, and CD spectroscopy.All compounds were evaluated for cytotoxic activity.     

Alkaloids from the leaves of Uncaria rhynchophylla and their inhibitory activity on NO production in lipopolysaccharide-activated microglia

Two new isomeric alkaloids, 18,19-dehydrocorynoxinic acid B (1) and 18,19-dehydrocorynoxinic acid (2), were isolated from the CHCl3 extract of the leaves of Uncaria rhynchophylla, together with four known rhynchophylline-type alkaloids, corynoxeine (3), isocorynoxeine (4), rhynchophylline (5), and isorhynchophylline (6), and an indole alkaloid glucoside, vincoside lactam (7). The structures of compounds 1 and 2 were elucidated by spectroscopic methods including UV, IR, HREIMS, 1D and 2D NMR, and CD experiments. The activity assay showed that compounds 3-6, with a C-16 carboxylic ester group, and 7 exhibited inhibitory activity on lipopolysaccharide (LPS)-induced NO release in primary cultured rat cortical microglia (IC 50: 13.7-19.0 microM). However, only weak inhibitory activity was observed for compounds 1 and 2, with a C-16 carboxylic acid group (IC 50: >100 microM).     

Bioactive constituents of the roots of Polyalthia cerasoides

A new dimeric aporphine alkaloid, bidebiline E (1), and a new natural product, octadeca-9,11,13-triynoic acid (2), along with three known sesquiterpenes, alpha-humulene (3), caryophyllene oxide (4), and (-)-alpha-cadinol (5), and four known isoquinoline alkaloids, laudanosine (6), codamine (7), laudanidine (8), and reticuline (9), were isolated from the roots of Polyalthia cerasoides. The structures of compounds 1 and 2 were established on the basis of their 1D and 2D NMR spectroscopic data. Among these isolates, 1, 2, 4, 7, and 8 exhibited antimalarial activity against Plasmodium falciparum, while 1- 3 showed antimycobacterial activity against Mycobacterium tuberculosis using in vitro assays.     

Xanthones from Garcinia parvifolia

Nine new xanthones, parvixanthones A-I (1-9), isolated from the dried bark of Garcinia parvifolia, were found to have a common 1,3,6,7-oxygenated pattern for their xanthone nucleus, but various oxygenated isoprenyl or geranyl substituent groups. The structures were determined by spectroscopic methods.     

Caryophyllene sesquiterpenoids from a fungicolous isolate of Pestalotiopsis disseminata

Three new caryophyllene-type sesquiterpene alcohols, 6-hydroxypunctaporonin E (1), 6-hydroxypunctaporonin B (2), and 6-hydroxypunctaporonin A (3), have been isolated from cultures of the fungicolous fungus Pestalotiopsis disseminata. The structures of 1-3 were determined mainly by analysis of 1D and 2D NMR data. The structure and absolute configuration of 6-hydroxypunctaporonin E (1) was confirmed through X-ray crystallographic analysis of its mono-bromobenzoate derivative. Compounds 1 and 2 showed activity against Gram-positive bacteria.     

Prenylated flavonoids from the heartwood of Artocarpus communis with inhibitory activity on lipopolysaccharide-induced nitric oxide production

A new prenylated chalcone, 3' ',3' '-dimethylpyrano[3',4']2,4,2'-trihydroxychalcone (1), was isolated from the heartwood of Artocarpus communis. Two flavonoid derivatives, (-)-cycloartocarpin (9) and (-)-cudraflavone A (10), were isolated as new isomers. In addition, eight known flavonoids, isobacachalcone (2), morachalcone A (3), gemichalcones B (4) and C (5), artocarpin (6), cudraflavone C (7), licoflavone C (8), and (2S)-euchrenone a(7) (11), were isolated and identified from this plant for the first time. Compounds 1-4, 6, and 11 exhibited potent inhibitory activity on nitric oxide production in RAW264.7 LPS-activated mouse macrophage cells with IC(50) values of 18.8, 6.4, 16.4, 9.3, 18.7, and 12.3 microM, respectively. The structure of compound 1 was elucidated by spectroscopic data analysis, including 1D and 2D NMR experiments.     

Sesquiterpenes and flavonol glycosides from Zingiber aromaticum and their CYP3A4 and CYP2D6 inhibitory activities

Three new sesquiterpenes, (2R,3S,5R)-2,3-epoxy-6,9-humuladien-5-ol-8-one (1), (2R,3R,5R)-2,3-epoxy-6,9-humuladien-5-ol-8-one (2), and (5R)-2,6,9-humulatrien-5-ol-8-one (3), and two new flavonol glycosides, kaempferol-3-O-(2,3-di-O-acetyl-alpha-l-rhamnopyranoside) (4) and kaempferol-3-O-(2,3,4-tri-O-acetyl-alpha-l-rhamnopyranoside) (5), were isolated from the EtOAc-soluble fraction of the water extract of Zingiber aromaticum, along with 13 known compounds (6-18). The structures of the isolated compounds were elucidated on the basis of spectroscopic and chemical analyses. The isolated compounds were tested for their inhibitory activity on the metabolism mediated by CYP3A4 or CYP2D6 using [N-methyl-(14)C]erythromycin or [O-methyl-(14)C]dextromethorphan as a substrate, respectively. Kaempferol-3-O-(2,3,4-tri-O-acetyl-alpha-l-rhamnopyranoside) (5) showed the most potent inhibitory activity (IC(50), 14.4 microM) on the metabolism mediated by CYP3A4, and kaempferol-3-O-methyl ether (14) inhibited CYP2D6 most potently (IC(50), 4.63 microM).     

Cytotoxic withaphysalins from the leaves of Acnistus arborescens

Three withaphysalins, rel-(17S,20R,22R)-5 beta,6 beta:18,20-diepoxy-4 beta-hydroxy-1,18-dioxowitha-2,24-dienolide(withaphysalin M) (1), rel-(17S,20R,22R)-5 beta,6 beta:18,20-diepoxy-4 beta-hydroxy-18-ethoxy-1-oxowitha-2,24-dienolide (withaphysalin F ethyl ether, withaphysalin O) (2), and rel-(17S,20R,22R)-5 beta,6 beta:18,20-diepoxy-4 beta-hydroxy-1,18-dioxowitha-24-enolide (withaphysalin N) (3), were isolated from the leaves of Acnistus arborescens. The structures were deduced from 1D ((1)H NMR, (13)C NMR, DEPT-(13)C NMR) and 2D (COSY, HMQC, HMBC) NMR analysis and the relative stereochemical assignments based on 1D NOESY correlations and analysis of coupling constants. Compounds 1 and 2 displayed potent cytotoxic activity against a panel of human cancer cell lines.     

New antiviral cassane furanoditerpenes from Caesalpinia minax.

A bioassay-guided study led to the isolation of five new cassane furanoditerpenes, designated as caesalmin C (1), D (2), E (3), F (4), and G (5), along with stigmasterol (6) from the seeds of Caesalpinia minax. The (1)H and (13)C NMR spectra were completely assigned by using a combination of 2D NMR analyses. The structures of all five furanoditerpenes were confirmed by X-ray analyses. The structure of 6 was verified by X-ray analysis for the first time. The bioassay results showed that the anti-Para3 virus activity of tetracyclic furanoditerpenoids 1-4 is more potent than that of the furanoditerpenoid lactone 5, which is in turn better than 6. As the major components of the plant possess significant potent activity, it may be feasible to develop new antiviral agents from this source.     

Indole glucoalkaloids from Chimarrhis turbinata and their evaluation as antioxidant agents and acetylcholinesterase inhibitors

As part of our study on bioactive agents from Brazilian rainforest plants, two new glucoalkaloids, 3,4-dehydro-strictosidine (1) and 3,4-dehydro-strictosidinic acid (2), were isolated from Chimarrhis turbinata, along with seven known glucoalkaloids, cordifoline (3), strictosidinic acid (4), strictosidine (5), 5 alpha-carboxystrictosidine (6), turbinatine (7), desoxycordifoline (8), and harman-3-carboxylic acid (9). The structures of the new alkaloids were established on the basis of comprehensive spectral analysis, mainly 1D and 2D NMR experiments, as well as high-resolution HRESIMS. Alkaloid 3 showed strong free-radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as pronounced antioxidant activity evidenced by redox properties measured by ElCD-HPLC. Additionally, alkaloids 1-9 were submitted to TLC screening for acetylcholinesterase inhibitors. Both 7 and 8 were shown to be moderate acetylcholinesterase inhibitors at a concentration of 0.1 and 1.0 microM, respectively. In an in vitro rat brain assay, 7 showed moderate activity (IC(50) 1.86 microM), compared to the standard compound, galanthamine (IC(50) 0.92 microM).     

Antioxidant chalcone glycosides and flavanones from Maclura (Chlorophora) tinctoria

Four chalcone glycosides (1-4), including three new natural products, and three flavanones (5-7) were isolated from the methanol extract of stem bark of Maclura tinctoria. The new compounds have been characterized as 4'-O-beta-D-(2' '-p-coumaroyl)glucopyranosyl-4,2',3'-trihydroxychalcone (1), 4'-O-beta-D-(2' '-p-coumaroyl-6' '-acetyl)glucopyranosyl-4,2',3'-trihydroxychalcone (2), and 3'-(3-methyl-2-butenyl)-4'-O-beta-D-glucopyranosyl-4,2'-dihydroxychalcone (3); the known derivatives were elucidated as 4'-O-beta-D-(2' '-acetyl-6' '-cinnamoyl)glucopyranosyl-4,2',3'-trihydroxychalcone (4), eriodictyol 7-O-beta-D-glucopyranoside (5), naringenin (6), and naringenin 4'-O-beta-D-glucopyranoside (7). Their structures were determined by 1D and 2D NMR and ESIMS. The antioxidant activity of all the isolated compounds was determined by measuring free-radical-scavenging effects using two different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay). The results showed that compound 3 was the most active in both antioxidant assays.