Four new steroidal glycosides from Lilium lancifolium Thunb. and their antitumor activity

Four new steroidal glycosides (1-4), including two steroidal saponins named lililancifoloside B and C (1-2), one pregnane glycoside named lililancifoloside D (3), and one C22-steroidal lactone glycoside named lililancifoloside E (4), together with five known ones (5-9), were isolated from the bulbs of Lilium lancifolium Thunb. By using spectroscopic analysis, including 1D, 2D NMR, and HR-ESI-MS, the structures of 1-4 were elucidated. All isolates were tested for their cytotoxic potential against the MCF-7, MDA-MB-231, HepG2, and A549 cell lines. Compound 6 distinguished out among them, IC₅₀ values of 3.31, 5.23, 1.78, and 1.49 μM against the four cell lines, respectively. Other compounds such as compound 3, 5, and 9 have also shown specific cytotoxic activity. Next, studies showed that compound 6 might cause HepG2 cells to undergo a cell cycle arrest during the G2/M phase and apoptosis.