Two new glycosides from Astragalus caprinus

A new glycoside of flavonol (1) and a new glycoside of a cycloartane-type triterpene (2) were isolated from the leaves and the roots of Astragalus caprinus, respectively. Their structures were elucidated in turn by spectroscopic data interpretation as 3-O-[[beta-D-xylopyranosyl(1-->3)-alpha-L-rhamnopyranosyl(1-->6)][beta-D-apiofuranosyl(1-->2)]]-beta-D-galactopyranosyl kaempferol (1) and 3-O-(beta-D-xylopyranosyl)-24-O-(beta-D-glucopyranosyl)-20,25-epoxycycloartane-3beta,6alpha,16beta,24alpha-tetrol (2).     

Three new flavonol galloylglycosides from leaves of Acacia confusa

Myricetin 3-O-(2"-O-galloyl)-alpha-rhamnopyranoside 7-methyl ether (1), myricetin 3-O-(3"-galloyl)-alpha-rhamnopyranoside 7-methyl ether (2), and myricetin 3-O-(2",3" -di-O-galloyl)-alpha-rhamnopyranoside (3), three new flavonol galloylglycosides, were isolated from leaves of Acacia confusa sampled from Chaoushi in the north of Taiwan. Their structures were established by analysis of spectroscopic data, and the compounds were evaluated for anti-hatch activity against brine shrimp.     

Antioxidant flavonol glycosides from Schinus molle

Chromatographic separation of aqueous MeOH extract of the leaves of Schinus molle L. has yielded two new acylated quercetin glycosides, named isoquercitrin 6'-O-p-hydroxybenzoate (12) and 2'-O-alpha-L-rhamnopyranosyl-hyperin 6'-O-gallate (13), together with 12 known polyphenolic metabolites for the first time from this species, namely gallic acid (1), methyl gallate (2), chlorogenic acid (3), 2'-alpha-L-rhamnopyranosyl-hyperin (4), quercetin 3-O-beta-D-neohesperidoside (5), miquelianin (6), quercetin 3-O-beta-D-galacturonopyranoside (7), isoquercitrin (8), hyperin (9), isoquercitrin 6'-gallate (10), hyperin 6'-O-gallate (11) and (+)-catechin (14). Their structures were established on the basis of chromatographic properties, chemical, spectroscopic (UV, 1H, 13C NMR) and ESI-MS (positive and negative modes) analyses. Compounds 4-9 and 11 exhibited moderate to strong radical scavenging properties on lipid peroxidation, hydroxyl radical and superoxide anion generations with the highest activities shown by 6 and 7 in comparison with that of quercetin as a positive control in vitro.     

Cytotoxic flavonol glycosides from Triplaris cumingiana

Three new compounds, 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-oxo-4H-chromen-3-yl-4,6-bis-O-beta-D-(3,4,5-trihydroxybenzoyl)glucopyranoside (1), 5,7-dihydroxy-2-(4-hydroxyphenyl)-4-oxo-4H-chromen-3-yl-5-O-alpha-L-(3,4,5-trihydroxybenzoyl)arabinofuranoside (2), and 2-hydroxy-4-O-alpha-L-(3,5,7-trihydroxy-4-oxo-4H-chromen-2-yl)phenylarabinofuranoside (3), were isolated from the young leaves of Triplaris cumingiana, together with two known compounds, quercetin 3-O-alpha-L-(5"-O-galloyl)arabinofuranoside (4) and quercetin 3-O-beta-D-(6"-O-galloyl)glucopyranoside (5). The structures of 1-3 were established by spectroscopic methods. Compounds 1-5 were evaluated for their cytotoxic activities against the MCF-7, H-460, and SF-268 human cancer cell lines.     

Acylated flavonol glycosides from the flower of Inula britannica

Three new acylated flavonol glycosides, patuletin 7-O-(6' '-isobutyryl)glucoside (1), patuletin 7-O-[6' '-(2-methylbutyryl)]glucoside (2), and patuletin 7-O-(6' '-isovaleryl)glucoside (3), were isolated from the n-BuOH extract of Inula britannica flowers by bioassay-guided fractionation, together with other known flavonoids. The structures were elucidated by 1D and 2D NMR, FABMS, and other spectral analyses. The eight flavonoids, including new compounds (1-3), patulitrin (7), nepitrin (8), axillarin (10), patuletin (11), and luteolin (12), showed profound antioxidant activity in DPPH assay and cytochrome-c reduction assay using HL-60 cell culture system.     

Two new hepatoprotective stilbene glycosides from Acer mono leaves

Two new stilbene glycosides, 5-O-methyl-(E)-resveratrol 3-O-beta-d-glucopyranoside (1) and 5-O-methyl-(E)-resveratrol 3-O-beta-D-apiofuranosyl-(1-->6)-beta-d-glucopyranoside (2), were isolated from the leaves of Acer mono, along with seven known compounds. Among these compounds, 1, 2, and quercetin (3) showed significant hepatoprotective activities against H(2)O(2)-induced toxicity in primary cultures of rat hepatocytes.     

Four new neuroprotective iridoid glycosides from Scrophularia buergeriana roots

Four new iridoid glycosides were isolated from a 90% MeOH extract of Scrophularia buergeriana roots and characterized as 8-O-E-p-methoxycinnamoylharpagide (1), 8-O-Z-p-methoxycinnamoylharpagide (2), 6'-O-E-p-methoxycinnamoylharpagide (3), and 6'-O-Z-p-methoxycinnamoylharpagide (4), respectively. In addition, three known iridoids were identified as E-harpagoside (5), Z-harpagoside (6), and harpagide (7). Compounds 1-7 significantly attenuated glutamate-induced neurotoxicity when added to primary cultures of rat cortical cells at concentrations ranging from 100 nM to 10 microM. The results obtained indicate that the iridoid glycosides isolated from S. buergeriana have significant protective effects against glutamate-induced neurodegeneration in primary cultures of rat cortical neurons.     

Triterpene glycosides from the roots of Astragalus flavescens

Six new triterpene saponins, 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (1), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (2), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (3), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (4), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzusapogenol A (5), and 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzusapogenol A (6), were isolated from the roots of Astragalus flavescens, together with the known trajanoside B, azukisaponin V, and astragalosides IV, VII, and VIII. Their structures were established mainly by 2D NMR techniques and mass spectrometry.     

麻疯树叶中3个新的糖苷类化合物

目的 研究麻疯树Jatrophacurcas叶的化学成分及其抗炎活性。方法 采用硅胶、大孔吸附树脂、半制备HPLC等色谱技术进行分离纯化,通过理化性质和NMR、HR-ESI-MS、ECD等现代波谱学技术对化合物的结构进行鉴定;采用Griess法测定化合物对脂多糖（LPS）诱导小鼠巨噬细胞（RAW264.7）释放炎症介质一氧化氮的抑制作用。结果 从麻疯树叶的正丁醇部位中分离得到6个化合物,分别鉴定为(+)-jatrointelignanB-4′′-O-β-D-glucopyranoside(1)、3-hydroxy-4,7-megastigmadien-3-one 9-O-[α-arabinopyranosyl-(1→6)-β-glucopyranoside](2)、β-紫罗兰酮-4-O-[β-呋喃芹糖-(1→6)-β-吡喃葡萄糖苷]（3）、byzantionosideB(4)、foliasalaciosideB1(5)、(6R,7E,9R)-9-hydroxy-4,7-megastigmadien-3-one9-O-[α-Larabinopyranosyl-(1→6)-β-D-gluc...     

Seasonal and sexual variety of Ginkgo flavonol glycosides in the leaves of Ginkgo biloba L.]

HPLC methods have been developed for the determination of Ginkgo flavonol glycosides in the Ginkgo biloba leaves obtained from May to November in the fallen leaves and in the leaves obtained from female and male trees. The method includes hydrolysis of the leaves and subsequent quantitative chromatographic assay of the aglycones, followed by calculation of Ginkgo flavonol glycosides content. The result shows that the leaves obtained in May have the highest content of 0.96%, and then the content decreases from May to August, and from August to November remains almost the same, that is 0.5% also. Fallen leaves have the lowest content of 0.44%. The content range is 0.96% to 0.44%. Male trees have higher content of glycosides than female trees.     

Four glycosides from the leaves of Abeliophyllum distichum with inhibitory effects on angiotensin converting enzyme

The bioassay-guided fractionation of the n-BuOH extract of Abeliophyllum distichum afforded acteoside (1), isoacteoside (2), rutin (3), and hirsutrin (4). Compounds 1-3 moderately inhibited the angiotensin I converting enzyme activity in a dose-dependent manner. Compounds 1-3 showed the 50% inhibitory concentration values of 228 micro g/mL, 290 micro g/mL, and 278 micro g/mL, respectively.     

3-Hydroxy-3-methylglutaryl flavonol glycosides from Oxytropis falcata

Five new 3-hydroxy-3-methylglutaryl (HMG) flavonol 3-O-glycosides, named oxytroflavosides A-E (1-5), and two new rhamnocitrin 3-O-glycosides, oxytroflavosides F and G (6 and 7) were isolated from the n-BuOH-soluble fraction of an EtOH extract of Oxytropis falcata together with seven known kaempferol glycosides (8-14), of which six were isolated from the genus Oxytropis for the first time. The structures of these compounds were elucidated by spectroscopic techniques and chemical methods. The absolute configuration of HMG in compounds 1-5 was determined to be S through spectroscopic analysis of the mevalonamide obtained by amidation and reduction of the HMG moiety. Compounds 1-10 were evaluated for anti-inflammatory activities using lipopolysaccharide-induced RAW 264.7 cells, but none of them showed inhibitory effects on NO production.     

膜荚黄芪叶黄酮类成分的研究

目的研究膜荚黄芪Astragalus membranaceus(Fish.)Bge.叶黄酮类成分。方法膜荚黄芪叶75%乙醇提取物的乙酸乙酯、正丁醇部位采用硅胶、ODS、制备型HPLC柱进行分离纯化,根据波谱数据鉴定所得化合物的结构。结果从中分离鉴定出13个化合物,分别为槲皮素(1)、槲皮素-3-O-β-D-葡萄糖苷(2)、鼠李柠檬素-3-O-β-D-葡萄糖苷(3)、rhamnocitrin-3-O-β-neohesperidoside(4)、rhamnocitrin-3-O-β-D-glucopyranoside(1→2″)-β-D-apiofuranosyl(5)、沙苑子苷(6)、黄豆黄素(7)、4',7-二羟基-3'-甲氧基异黄酮(8)、染料木素(9)、芒柄花素-7-O-β-D-葡萄糖苷(10)、染料木苷(11)、黄豆黄苷(12)、银椴苷(13)。结论化合物5、8、13为首次在黄芪属植物中分离得到,化合物2为首次在该植物中分离得到。     

大叶冬青叶中2个新的三萜皂苷(英文)

大叶冬青为苦丁茶的主要基源植物,三萜皂苷为其主要的活性和特征性成分。该研究从大叶冬青叶中分离得到了2个新的三萜皂苷类化合物,大叶冬青皂苷R(1)和大叶冬青皂苷S(2),并根据NMR,MS等波谱方法和理化性质鉴定了其化学结构。其中大叶冬青皂苷R为第1个含有19-28内酯环的三萜皂苷。     

Antioxidant flavan-3-ols and flavonol glycosides from Maytenus aquifolium

TLC autographic assay revealed, in the EtOAc extract obtained from leaves and root bark of Maytenus aquifolium (Celastraceae), the presence of fi ve compounds exhibiting antioxidant properties towards beta-carotene. They were isolated and identified as epigallocatechin (1), (+) ouratea-catechin (2), proanthocyanidin (3), kaempferol 3-O-alpha-L-rhamnopyranosyl (1-->6)-O-[beta-D-glucopyranosyl (1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)]-O-beta-D-glucopyranosyl (4) and quercetin 3-O-alpha-L-rhamnopyranosyl (1-->6)-O-[beta-D-glucopyranosyl (1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)]-O-beta-D-glucopyranosyl (5). The isolates were investigated for their redox properties using cyclic voltammetry and for their radical scavenging abilities through spectrophotometric assay on the reduction of 2,2-diphenyl-pycryl hydrazyl (DPPH). These results were correlated to the inhibition of beta-carotene bleaching on TLC autographic assay and to structural features of the flavonoids.     

Hepatoprotective flavonol glycosides of Saururus chinensis herbs

Two flavanol glycosides, quercetin-3-O -β-D -glucuronopyranoside (1) and quercetin-3-O -β-D -glucuronopyranosyl methyl ester (2), from the aerial part of Saururus chinensis which possess hepatoprotective activities have been identified. Both compounds 1 and 2 significantly reduced the level of glutamic pyruvic transaminase released from intoxicated rat hepatocytes and resulted in 78% and 82% blockade of the toxicity at 200 μM , respectively. Furthermore, these compounds also reduced the level of toxicity as measured by the release of sorbitol dehydrogenase and resulted in 76% and 83% blockade of the toxicity at 200 μM , respectively. Also, these glycosides significantly increased the activity of glutathione-S-transferase in the injured rat hepatocytes and resulted in 68% and 86% blockade of the toxicity at 200 μM , respectively. Finally, these flavonol glycosides promoted the preservation of glutathione in carbon tetrachloride-intoxicated hepatocytes by 46% and 52% of the untreated control, respectively. © 1997 John Wiley & Sons, Ltd.     

Antioxidative glycosides from the leaves of Ligustrum robustum

Phytochemical investigation of the ethanol extract of the leaves of Ligustrum robustum, monitored by a bioassay involving the hemolysis of red blood cells induced by 2,2'-azo-bis(2-amidinopropane) dihydrochloride, led to the isolation of three new glycosides, ligurobustosides M (1), N (2), and O (3), along with 10 known ones, osmanthuside B (4), osmanthuside B6 (5), acteoside (6), ligupurpuroside A (7), ligupurpuroside B (8), ligurobustoside C (9), ligurobustoside E (10), ligurobustoside I (11), cosmosiin (12), and rhoifolin (13). The structures of the new compounds were elucidated by spectroscopic methods. Seven of the glycosides showed stronger antioxidant effects than the standard, trolox.     

Steroidal glycosides from the leaves of Cestrum nocturnum

Further phytochemical analysis aimed at the steroidal glycoside constituents of the leaves of Cestrum nocturnum has resulted in the isolation of eight new steroidal glycosides (1-8), which were classified into a spirostanol saponin (1), a furostanol saponin (2), a pseudo-furostanol saponin (3), two pregnane glycosides (4, 5), two cholestane glycosides (6, 7), and pregnane-carboxylic acid gamma-lactone glycoside (8), and of two known spirostanol glycosides (9, 10). The structures of the new compounds were elucidated on the basis of chemical and spectroscopic evidence.     

Iridoid glycosides from the leaves of Morinda citrifolia.

A new iridoid glucoside (1), named citrifolinoside A, was isolated from the leaves of Morinda citrifolia along with the known iridoids asperuloside and asperulosidic acid. The structure of 1 was established by interpretation and full assignments of NMR spectroscopic data.     

Sedative activity of two flavonol glycosides isolated from the flowers of Albizzia julibrissin Durazz

The flowers of Albizzia julibrissin are used as a sedative in oriental traditional medicine. The phytochemical study of this plant allowed the isolation of two flavonol glycosides, quercitrin (1) and isoquercitrin (2). The sedative activity of these compounds was evaluated, and both compounds 1 and 2 increased pentobarbital-induced sleeping time in dose-dependent manner in mice. These results support the use of the flowers of this plant as a sedative agent.