ABSTRACT
OBJECTIVE To study the triterpenoid saponins from Anemone rivularis var. flore-minore and their antitumor activities. METHODS The n-butanol extract of 70％ ethanol extract from rhizome of the plant was separated. The triterpenoid saponins were separated and purified by normal silica gel column chromatography ，reversed phase ODS column chromatography ， Sephadex LH- 20 gel column chromatography and semi-preparation high performance liquid chromatography. The structures of these saponins were identified by spectral analysis （NMR and MS ）and physical and chemical properties. MTT assay was used to test the proliferation inhibitory activity of the compounds against five kinds of human tumor cells （HL-60 cells，A549 cells，HepG2 cells，HeLa cells and U 87MG cells ）. The apoptosis inducing effect of compound 7 on U 87MG cells was evaluated by flow cytometric Annexin V-FITC/PI staining test. RESULTS：Sixteen triterpenoid saponins were obtained and identified as 3 β-O-β-D-xylopyranosyl-（1→2）-α-L-arabinopyranosyl-oleanolic acid-28-O-α-L-rhamnopyranosyl- （1→4） -β-D-glucopyranosyl-（1→6）-β-D-glucopyranoside（1），3β-O-L-arabinopyranosyl oleanolic acid- 28-O-β-D-glucopyranoside（2），saponin B （3）， 163.com oleanolic acid- 3β-O-β-D-glucopyranosyl-（1→2）-α-L-arabino- pyranoside（4），HN-saponin F （5），clematoside S （6），prosapogenin CP 4（7），cussonside B （8），pulsatilla saponin C （9）， clemastanoside D （10），3 β-O-β-D-glucopyranosyl-（1→2）-β-L-arabinopyranosyl-hederagenin-28-O-β-D-glucopyranoside（11）， ciwujianoside C 3（12），ciwujianoside A 1（13），huzhangoside D （14），kalopanaxsaponin B （15）and hederacolchiside E （16）. Compounds 3，4，6-9 displayed inhibitory activities on the proliferation of tumor cells to different extent ，and compound 7 had the strongest activity ；compound 7 induced the apoptosis of U 87MG cell so as to inhibit the proliferation of cancer cells in a time-dependent manner. CONCLUSIONS The obtained 16 saponins are all identified as oleanolane-type ，among which compound 1 is a new compound. The monodesmosidic saponins ，the sugar chain of which attached at C- 3 and a free carboxyl at C- 28， possess stronger antitumor activity than others.