Aspidiatas C and D, two new spirostanol saponins from Aspidistra triradiata and their cytotoxic activities

Aspidiatas C and D (1 and 2), two new spirostanol saponins, were isolated along with two known compounds, (25 R*)-spirost-5-en-3 beta-yl alpha-L-rhamnopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 4)-[alpha-L-rhamnopyranosyl-(1 -> 2)]-beta-D-glucopyranoside (3), (25 R*)-spirost-5-en-3 beta-yl alpha-L-rhamnopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 4)-beta-D-glucopyranoside (4) from the whole plant of Aspidistra triradiata collected in Vietnam. The chemical structures were determined by HRESIMS, 1D- and 2D-NMR analysis, and comparison with published data. Compound 3 exhibited potent cytotoxicity against MCF7, HepG2, SK-LU-1, and HT-29 human cancer cell lines with IC50 values ranging from 0.19 to 0.65 mu M. Compounds 1, 2, and 4 displayed moderate cytotoxic effects with IC50 values ranging from 12.32 to 82.27 mu M. Compounds 1-4 were isolated from the genus Aspidistra for the first time.