Isoflavone diglycosides from Glycosmis pentaphylla

Abstract

Six new apiosyl-(1-->6)-glucosyl isoflavones (1-6) and four known ones were isolated from the stems of Glycosmis pentaphylla. The structures of the new glycosides are 3',7-dihydroxy-4',5,6-trimethoxyisoflavone 7-O-(5-O-trans-p-coumaroyl)-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (1), 2',7-dihydroxy-4',5',5,6-tetramethoxyisoflavone 7-O-(5-O-trans-p-coumaroyl)-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (2), 2',7-dihydroxy-4',5',5,6-tetramethoxyisoflavone 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (3), 7-hydroxy-4',8-dimethoxyisoflavone 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (4), 7-hydroxy-4',6-dimethoxyisoflavone 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (5), and 4',5-dihydroxy-3',7-dimethoxyisoflavone 4'-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (6). Their structures were established primarily by NMR experiments and chemical methods.