Six new isoflavones and a 5-deoxyflavonol glycoside from the leaves of Ateleia herbert-smithii

Six new isoflavones, 5-methoxy-6,7:3',4'-bis(methylenedioxy)isoflavone (1), 3'-methoxy-6,7A',5'-bis(methylenedioxy)isoflavone (2), 5,2'-dimethoxy-6,7:4',5'-bis(methylenedioxy)isoflavone (3), 5,3'-dimethoxy-6,7: 4',5'-bis(methylenedioxy)isoflavone (4), 5-hydroxy-7,3',4'-trimethoxyisoflavone (5), and 5,6,7,3',4'-pentamethoxyisoflavone (6), were obtained from diethyl ether extracts of the leaves of Ateleia herbert-smithii together with 11 known isoflavones and two chalcones. Four of the isoflavones (1-4) are characterized by a unique bis-methylenedioxyl substitution pattern. A new flavonol glycoside, 5-deoxyisorhamnetin 3-O-alpha-L-rhamnopyranosyl(1"' --> 6")-beta-D-glueopyranoside (20), and three known flavonol 3-O-glycosides were obtained from aqueous methanol extracts of leaves of the same species. Spectroscopic methods were used to determine the structures of the compounds. The significance of their occurrence in A. herbert-smithii is discussed from both biosynthetic and taxonomic viewpoints.