Cytotoxic saponins from New Zealand Myrsine species

The observed biological activity in two New Zealand Myrsine species has been shown to be due to the presence of triterpene saponins. From Myrsine australis a series of eight oleanane-type saponins was obtained, with compounds 1-4 and 7 and 8 being novel. Also isolated were ardisiacrispin A [5] and ardisiacrispin B [6]. The structures of the new compounds were determined by chemical and spectroscopic techniques. Extracts of Myrsine salicina yielded only one saponin, 5. Saponins 1-8 were shown to be combinations of four oleanane triterpenes bonded to beta-D-xylp(1-->2)-beta-D-glcp(1-->4)-[beta-D-glcp(1-->2)]-alpha-L -arap (compounds 1, 3, 5, 7) and this same tetrasaccharide with alpha-L-rhap replacing the beta-D-xylp unit (compounds 2, 4, 6, 8).