Antioxidative flavonoids from the leaves of Morus alba

Nine flavonoids (1-9) were isolated from the leaves of Morus alba (Moraceae ). The structures of compounds were determined to be kaempferol-3-O-beta-D- glucopyranoside (astragalin, 1) kaempferol-3-O-(6 "-O-acetyl)-beta-D-glucop yranoside (2), quercetin-3-O-(6 "-O-acetyl)-beta-D-glucopyranoside (3), que rcetin-3-O-beta-D-glucopyranoside (4), kaempferol-3-O-alpha-L-rhamnopyranos yl-(1-->6)-beta-D-glucopyranoside (5), quercetin-3-O-alpha-L-rhamnopyranosy l-(1-->6)-beta-D-glucopyranoside (rutin, 6), quercetin-3-O-beta-D-glucopyra nosyl-(1-->6)-beta-D-glucopyranoside (7), quercetin-3,7-di-O-beta-D-glucopy ranoside (8) and quercetin (9) on the basis of spectroscopic and chemical s tudies. Compounds 7 and 9 exhibited significant radical scavenging effect o n 1,1-diphenyl-2-picryl-hydrazyl radical.