Cardenolides from Saussurea stella with cytotoxicity toward cancer cells.

Three new cardenolides, 3-O-beta-D-fucopyranosylstrophanthidin (1), 3-O-beta-D-quinovopyranosylperiplogenin (2), and 3-O-beta-D-glucopyranosyl-(1 --> 4)-alpha- l-rhamnopyranosylcannogenin (3), together with seven known cardenolides (4- 10), were isolated from a cytotoxic ethanol extract of the whole dried plants of Saussurea stella. The structures of these compounds were established by spectroscopic and chemical methods. When the cytotoxicity of compounds 2- 10 toward Bel-7402 human hepatoma cells and BGC-823 human gastric cancer cells was evaluated, all compounds showed IC 50 values of <1 microM for both cell lines. This is the first report of cardenolides occurring in a species of the family Asteraceae.