Triterpenoid saponins from the roots of Clematis argentilucida

Abstract

Reinvestigation of the n-BuOH extract of the roots of Clematis argentilucida led to the isolation of a new ursane-type triterpenoid saponin 1 and a new taraxerane-type saponin 2, four known saponins 3–6 first isolated from the species, together with seven saponins 7–13 reported in the previous papers. The structures of saponins 1–6 were elucidated by extensive spectroscopic analysis and chemical evidences. The ursane-type and taraxerane-type triterpenoid saponins were obtained from genus Clematis for the first time, and the aglycone of saponin 1, 3β,28-dihydroxy-18αH-ursan-20-en was first encountered. The cytotoxicity of all the saponins was evaluated against human glioblastoma U251MG cell lines. The monodesmosidic saponins 1, 2 and 4–8 exhibited cytotoxic activity against the cells with IC50 values ranging from 6.95 to 38.51μM.