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排序方式: 共有229条查询结果,搜索用时 158 毫秒
101.
Nhiem NX Tai BH Quang TH Kiem PV Minh CV Nam NH Kim JH Im LR Lee YM Kim YH 《Bioorganic & medicinal chemistry letters》2011,21(6):1777-1781
One new ursane-type triterpenoid glycoside, asiaticoside G (1), five triterpenoids, asiaticoside (2), asiaticoside F (3), asiatic acid (4), quadranoside IV (5), and 2α,3β,6β-trihydroxyolean-12-en-28-oic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester (6), and four flavonoids, kaempferol (7), quercetin (8), astragalin (9), and isoquercetin (10) were isolated from the leaves of Centella asiatica. Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy. The structure of new compound 1 was determined to be 2α,3β,23,30-tetrahydroxyurs-12-en-28-oic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester. The anti-inflammatory activities of the isolated compounds were investigated on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Asiaticoside G (1) potently inhibited the production of nitric oxide and tumor necrosis factor-α with inhibition rates of 77.3% and 69.0%, respectively, at the concentration of 100 μM. 相似文献
102.
103.
M. I. Kusaykin M. S. Pesentseva A. S. Sils’chenko S. A. Avilov V. V. Sova T. N. Zvyagintseva V. A. Stonik 《Russian Journal of Bioorganic Chemistry》2006,32(1):63-70
An aryl sulfatase of unusual specificity has been isolated from the liver of marine mollusk Littorina kurila. It hydrolyzes p-nitrophenyl sulfate, does not affect the natural fucoidan, and catalyzes splitting off the sulfate group in position C4 of xylose residues within the carbohydrate chains of holostane triterpene glycosides from sea cucumbers. The properties of the enzyme were studied at pH 5.4. The protein is homogeneous according to electrophoresis and has M 45 ± 1 kDa. The semiinactivation time of the enzyme at 60°C is 20 min, and its K m value for the hydrolysis of p-nitrophenyl sulfate is 8.7 ± 1 mM. It was shown that natural sulfated polyhydroxysteroids inhibit activity of the sulfatase; their I 50 values depend on their structures and are within the range from 10?3 to 10?5 M. 相似文献
104.
105.
106.
许祥誉 《植物分类与资源学报》1982,4(1):1-3
伞花紫堇组(Sect. Denecinctae Fendde ex C.Y.Wu et T.Y.Shu)是集中分布在我国云南,四川和西藏接壤地区的特有高山类群,其独特的形态特征在紫堇属中有别于其他各组,是十分自然的一类。1928年Fedde建立本组(Fedde,Repert.25:221,1928),后来他又将它降为亚组(Subsect.Benecinctae Fedde) 置于真紫堇组(Sect.Eucorydalis Prantl)之下(Fedde in Engler et Prantl,Naturl Pflanzenfam.17b:134,1936),鉴于Fedde在建立本组时缺乏拉丁描述,以及近年来的一些新发现已为Fedde原有记载所不能包括,所以作者除恢复 Fedde首次建立的组的等级外还作了拉丁的补充描述。 相似文献
107.
海莲内生真菌Pestalotiopsis clavispora代谢产物研究 总被引:4,自引:2,他引:2
从海莲内生真菌Pestalotiopsis clavispora发酵液乙酸乙酯萃取物中分离得到9个化合物。根据波谱数据,化合物1-9结构分别鉴定为:3β,22β,24-三羟基齐墩果-12-烯,乌苏酸,3-羟基-4-甲氧基苯乙烯,邻苯二甲酸二异丁酯,3,4-二羟基苯乙醇,对羟基苯乙醇,3β-羟基-5α,8α-过氧化麦角甾-6,22-二烯,麦角甾-4,6,8(14),22-四烯-3-酮,胸苷。9个化合物均为首次从该内生真菌中分离得到。 相似文献
108.
Max Henry 《Phytochemistry Reviews》2005,4(2-3):89-94
The chemical structure of triterpenoid saponins is quite complicated, especially the glucuronide oleanane-type triterpene
carboxylic acid 3,28-bidesmosides (GOTCAB) saponins. Moreover, triterpenoid saponins are numerous as a result of this complicated
structure. This review tries to explain this diversity in terms of plant classification and phylogeny. The study focuses on
the three main successive steps of the biosynthetic pathway of the triterpenoid saponins: cyclisation, oxidation and glycosylation
showing the relationship between triterpenols and sterols in terms of cell membrane evolution and the importance of which
metabolic intermediates involved as aglycones of the triterpenoid saponins, represented progressively less and less in the
advanced groups of the plant kingdom as they are more and more oxidised. This oxidation seems to reflect a better adaptation
to new environmental conditions of some of these groups. By their enormous chemical diversity, the triterpenoid saponins seem
to be good candidates to study the phylogeny of the flowering plants. A first attempt is given using recent advances in botanical
classification for the orders and families by the Angiosperm Phylogenic Group (APG). This study was simplified in the first
step focusing only on the “gypsogenin group” of the GOTCAB saponins. For example, as a result, these compounds are mainly
concentrated in advanced groups such as Caryophyllideae, primitive Rosideae and Asterideae. 相似文献
109.
Two New Saponins from Lysimachia capillipes Hemsl. 总被引:1,自引:0,他引:1
Jing-Kui TIAN Zhong-Mei ZOU Li-Zhen XU Shi-Lin YANG 《植物学报(英文版)》2005,47(10):1271-1275
To investigate the saponins from whole plants of Lysimachia capillipes Hemsl., two new saponins, named capilliposide E (1) and capilliposide F (2), were isolated. The structures of the new sa ponins were elucidated as 3 β, 22α-dihydroxy- 16α-acetat-28→ 13 -lactone-oleanane-3 -O- [β-D-glucopyranosyl(1→2)-α-L-arabinpyranoyl]-22-O-β-D-glucopyranoside (1) and 3 β, 22α-dihydroxy- 16α-acetat-28→ 13-1actone-oleanane-3-O- { [β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→4)]-α-L-arabinpyranoyl }-22-O-βD-glucopyranoside (2). The structures of these compounds were determined by 1D- and 2D-NMR, MS techniques, and chemical methods. 相似文献
110.
飞龙掌血中三萜酸成分研究 总被引:5,自引:0,他引:5
从芸香科植物飞龙掌血中提取分离出4个新三萜酸,经波谱数据分析,分别鉴定为2α,3α,19α-trihydroxy11-oxo-urs-12-en-28-oic acid(1),2α,3α,11α,19α-tetrahydroxy-urs-12-en-28-oic acid(2),2α,3α-dillydroxy-19-oxo-18,19-seco-urs-11,13(18)-diene-28-oic acid(3)和2α,3α,19α-trihydroxy-olean-11,13(18)-dien-28-oic acid(4)。还分离鉴定出已知成分野鸭春酸(5)、arjunic acid(6)、飞龙掌血素、勒钩内脂和β-谷甾醇。 相似文献