New Metabolites of Rhodiola rosea I. Glycosides of Herbacetin and Gossypetin

New O-glycosides of herbacetin and gossypetin ( 1 – 6 ) and eight known compounds were isolated from leaves of Rhodiola rosea L. [ Sedum roseum (L.) Scop., Crassulaceae]. According to UV, IR, and NMR spectroscopic and mass spectrometric data, the isolated compounds were herbacetin-3-O-(3′′ -O-malonyl)- β -Dglucopyranoside-7-O- β -D-glucopyranoside-8-O- β -D-glucuronopyranoside (rhodirosin A, 1 ), herbacetin- 3-O-(3′′,4′′-di-O-acetyl)- β -D-glucopyranoside-8-O- β -D-glucuronopyranoside (rhodirosin B, 2 ), gossypetin- 8-O-(2′′-O-malonyl)- β -D-glucuronopyranoside (rhodirosin C, 3 ), gossypetin-8-O-(2′′-O-acetyl)- β -Dglucuronopyranoside (rhodirosin D, 4 ), herbacetin-8-O-(2′′-O-malonyl)- β -D-glucuronopyranoside (rhodirosin E, 5 ), and herbacetin-8-O-(2′′ -O-acetyl)- β -D-glucuronopyranoside (rhodirosin F, 6 ). Flavonoids 3 and 4 possessed the highest antiradical activity and inhibited the activity of α -amylase.