ABSTRACT
Objective: To study the chemical constituents of flavonoid glycosides in the extract from Ginkgo biloba leaves used for injection. Methods: The constituents of flavonoid glycosides in the 70% ethanol extract from G. biloba leaves were isolated and purified by chromatography over silica gel, MCI, ODS, Sephadex LH-20 columns and RP-HPLC. The structures were identified on the basis of physicochemical properties and spectral data analyses. Results: Sixteen compounds were isolated and identified as 5, 7-dihydroxyl-4'-methoxylflavonol-3-O-rutinoside (1), quercetin-3-O-(2″, 6″-α-L-dirhamnopyranosyl)-β-D-glucoside (2), quercetin- 3-O-[2″-(6‴-p-coumaroyl)-β-D-glucopyranosyl] -α-L-rhamnopyranosyl-7-O-β-D-glucoside (3), isorhamnetin-3-O-(2″, 6″-α-L-dirhamnopyranosyl)-β-D-glucoside (4), rutin (5), luteolin-7-O-β-D-glucoside (6), quercetin-3-O-β-D-glucoside (7), quercetin- 3-O-(2″-β-D-glucopyranosyl)-α-L-rhamnoside (8), kaempferol-3-O-rutinoside (9), quercetin-3-O-α-L-rhamnoside (10), isorhamnetin-3-O-rutinoside (11), apigenin-7-O-β-D-glucoside (12), syringetin-3-O-rutinoside (13), kaempferol-3-O-(2″- β-D-glucopyranosyl)-α-L-rhamnoside (14), quercetin-3-O-α-L-rhamnopyranosyl-2″- (6‴-p-coumaroyl)-β-D-glucoside (15), and kaempferol-3-O-α-L-rhamnopyranosyl-2″- (6‴-p-coumaroyl)-β-D-glucoside (16). Conclusion: UPLC-PDA shows that all the compounds are flavonoid glycosides in the leaves of G. biloba and are marked in the extract and injection. Compound 1 is isolated from this plant for the first time, named flavonol glycoside K.