Cytotoxic acylated triterpene saponins from the husks of Xanthoceras sorbifolia

Four new oleanane-type triterpene saponins, xanifolia-Y(0) (1), xanifolia-Y(2) (2), xanifolia-Y(3) (3), and xanifolia-Y(7) (4), were isolated from the husks of Xanthoceras sorbifolia along with two known analogues, xanifolia-Y(8) (5) and xanifolia Y(10) (6). The structures of 1-4 were determined by spectroscopic data interpretation and chemical degradation. Compounds 1-6 were evaluated for their cell-growth inhibition activity toward human ovarian cancer cells (OVCAR3) by a MTT assay, and the IC(50) values ranged from 4 to 13 mu M. On the basis of the results obtained, it is concluded that a C-3 trisaccharide with a galactose and acylation with an angeloyl group at both C-21 and C-22 are important for cell inhibition activity for this class of compounds.