Four new steroidal glycosides from Solanum torvum and their cytotoxic activities

Two novel C-22 steroidal lactone saponins, namely solanolactosides A, B (1, 2) and two new spirostanol glycosides, namely torvosides M, N (3, 4) were isolated from ethanol extract of aerial parts of Solanum torvum. Their structures were characterized as solanolide 6-O-[α-l-rhamnopyranosyl-(1 → 3)-O-β-d-quinovopyranoside] (1), solanolide 6-O-[β-d-xylopyranosyl-(1 → 3)-O-β-d-quinovopyranoside] (2), yamogenin 3-O-[β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside] (3) and neochlorogenin 3-O-[β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside] (4) on the basis of spectroscopic analysis. The cytotoxicities of the saponins (1-4) were evaluated in vitro against a panel of human cancer cell lines. Compounds 3 and 4 showed significant cytotoxic activity with the cell lines.