Bufadienolide and spirostanol glycosides from the rhizomes of Helleborus orientalis

The rhizomes of Helleborus orientalis have been analyzed for the bufadienolide glycoside and spirostanol saponin constituents, resulting in the isolation of a new bufadienolide rhamnoside (1), along with two known bufadienolide glycosides (2 and 3) and five new spirostanol saponins (4-8). The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including 2D NMR, and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activities against cultured tumor and normal cells.