Oleanolic acid glycosides from two species of Olax: Olax wildemanii and Olax subscorpioidea
Abstract
Three undescribed oleanolic acid glycosides, together with four known ones, were isolated from root barks of two species of Olax: 3-O-alpha-L-rhamnopyranosyl-(1 -> 3)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-glucuronopyranosyloleanolic acid and 3-O-alpha-L-rhamnopyranosyl-(1 -> 3)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-glucuronopyranosyloleanolic acid 28-O-beta-D-glucopyranosyl ester from Olax wildemanii, and 3-O-beta-D-glucopyranosyl-(1 -> 4)-[beta-D-glucopyranosyl- (1 -> 3)]-beta-D-glucuronopyranosyloleanolic acid from Olax subscorpioidea. Their structures were elucidated by spectroscopic methods including 1D and 2D NMR experiments in combination with mass spectrometry. These molecules showed no antimicrobial activity against Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa.