Four new isoflavones from Ampelopsis grossedentata.

Four new isoflavones have been isolated from the BuOH extract of Ampelopsis grossedentata Hand.-Mazz. Based on spectral and chemical methods, their structures were elucidated as 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 1; 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 6-O-beta-D-glucopyranoside 2; 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 6-O-alpha-L-rhamnopyranoside 3; 6,7-dihydroxy-3'-methoxy-4',5'-methylenedioxyisoflavone 6-O-beta-D-xylopyranosyl-(1-6)-beta-D-glucopyranoside 4. This is the first report on isolation of isoflavones from this plant.