Cytotoxic 16-β-[(d-xylopyranosyl)oxy]oxohexadecanyl triterpene glycosides from a Malagasy plant, Physena sessiliflora

Eight triterpene glycosides were isolated from the leaves of Physena sessiliflora, and their structures were elucidated based on analysis of spectroscopic data. Among these compounds, the 16-β-[(d-xylopyranosyl)oxy]oxohexadecanyl triterpene glycoside, Physenoside S7, exhibited the strongest cytotoxic activity in the brine shrimp lethality assay.