Quadranosides VI - XI, six new triterpene glucosides from the seeds of Combretum quadrangulare

Abstract

Six new triterpene glucosides, quadranosides VI - XI (1 - 6), belonging to three different [ursane- (1 - 4), oleanane- (5) and lupane-type (6)] triterpene classes, have been isolated from a MeOH extract of the seeds of Combretum quadrangulare Kurz (Combretaceae), together with nine known compounds, rosamutin (7), 28-O-β-D-glucopyranosyl-6β,23-dihydroxytormentic acid (8), arjunetin (9), arjunglucoside II (10), combreglucoside (11), chebuloside II (12), vitexin (13), (+)-catechin (14) and (-)-epigallocatechin (15). The structures of these compounds were elucidated by spectroscopic analysis.