Oleanane-type saponins from Anemone taipaiensis and their cytotoxic activities

Phytochemical investigation of the n-BuOH extract of the rhizomes of Anemone taipaiensis led to the isolation of three new oleanane-type triterpenoid saponins (1-3), together with four known saponins (4-7). Their structures were elucidated on the basis of spectroscopic analysis and chemical derivatization. All the compounds were isolated for the first time from A. taipaiensis. The cytotoxicity of these compounds was evaluated in five human cancer cell lines including A549 (lung carcinoma), HeLa (cervical carcinoma), HepG2 (hepatocellular carcinoma), HL-60 (promyelocytic leukemia), and U87MG (glioblastoma). The monodesmosidic saponin 4 exhibited cytotoxic activity toward all cancer cell lines, with IC50 values ranging from 6.42 to 18.16 μM. In addition, the bisdesmosidic saponins 1 and 7 showed selective cytotoxicity against the U87MG cells.