Biologically Active Secondary Metabolites from Ginkgo biloba
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- 作者：Erdal Bedir ; Irem I. Tatli ; Riaz A. Khan ; Jianping Zhao ; Satoshi Takamatsu ; Larry A. Walker ; Peter Goldman ; and Ikhlas A. Khan
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2002
- 出版时间：May 22, 2002
- 年：2002
- 卷：50
- 期：11
- 页码：3150 - 3155
- 全文大小：94K
- 年卷期：v.50,no.11(May 22, 2002)
- ISSN：1520-5118
文摘
Three new compounds, (7E)-2
,3
-dihydroxy-megastigm-7-en-9-one (1), 3-[5,7-dihydroxy-2-(4-methoxyphenyl)-4-oxo-4H-chromen-8-yl]-4-methoxybenzoic acid (2), and 4'-O-methyl myricetin 3-O-(6-O--L-rhamnopyranosyl)--D-glucopyranoside (3), were isolated from Ginkgo biloba, together with27 known compounds. The structures of the new compounds were determined primarily from 1D-and 2D-NMR analysis. The 4-O-methylbenzoic acid structural feature at C-8 in 2 is encountered forthe first time. The antioxidant activities of 29 compounds isolated from Ginkgo biloba were evaluatedon intracellular reactive oxygen species in HL-60 cells. It was found that quercetin, kampferol, andtamarixetin had antioxidant activity that was approximately 3-fold greater than that of their respectiveglycosides and also approximately 3-fold greater than that of a standard ascorbic acid with an IC50at maximum effectiveness.Keywords: Ginkgo biloba; flavonoid; megastigmane; antioxidant activity
,3-dihydroxy-megastigm-7-en-9-one (1), 3-[5,7-dihydroxy-2-(4-methoxyphenyl)-4-oxo-4H-chromen-8-yl]-4-methoxybenzoic acid (2), and 4'-O-methyl myricetin 3-O-(6-O--L-rhamnopyranosyl)--D-glucopyranoside (3), were isolated from Ginkgo biloba, together with27 known compounds. The structures of the new compounds were determined primarily from 1D-and 2D-NMR analysis. The 4-O-methylbenzoic acid structural feature at C-8 in 2 is encountered forthe first time. The antioxidant activities of 29 compounds isolated from Ginkgo biloba were evaluatedon intracellular reactive oxygen species in HL-60 cells. It was found that quercetin, kampferol, andtamarixetin had antioxidant activity that was approximately 3-fold greater than that of their respectiveglycosides and also approximately 3-fold greater than that of a standard ascorbic acid with an IC50at maximum effectiveness.Keywords: Ginkgo biloba; flavonoid; megastigmane; antioxidant activity