A new major triterpene saponin from the roots of Cucurbita foetidissima

Foetidissimoside B (1), a novel triterpene saponin, was isolated from the r oots of Cucurbita foetidissima. Based on spectroscopic data, especially dir ect and long-range heteronuclear 2D NMR analysis and on chemical transforma tions, the structure of 1 was elucidated as 3-O-beta-D-glucuronopyranosyl-e chinocystic acid 28-O-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranosyl(1- ->3)-[beta-D-xylopyranosyl (1-->4)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L -arabinopyranoside. Compound 1 did not show any ability to potentiate in vi tro cisplatin cytotoxicity in a human colon cancer cell line.