Triterpenoid saponins from the roots of Clematis argentilucida and their cytotoxic activity.

The reinvestigation of the n-BuOH extract of the roots of Clematis argentilucida led to the isolation of four new oleanane-type triterpenoid saponins, 1-4, four known saponins, 5-8, first isolated from the species, together with ten saponins, 9-18, reported in the preceding papers. The structures of saponins 1-8 were elucidated by extensive spectroscopic analysis and chemical evidences. The cytotoxicity of all the saponins were evaluated against human tumor HL-60, HepG-2, and SGC-7901 cell lines. The monodesmosidic saponins 4, 7, 8, and 14-18 exhibited cytotoxic activity against the three cell lines with IC50 values in the range of 0.87-19.48 µM.