ABSTRACT
Objective: To study the active triterpenoid saponins of Tujia ethnomedicine Kouziqi (Panax japonicus var. major). The antitumor activity was screened and the relationship between the structure and activity of the compounds was discussed. Methods: The ethanol extract of Kouziqi was isolated by Silica gel, ODS and MCI column chromatograph and purified by preparative HPLC. The structures were elucidated on the basis of spectroscopic analysis and compared with literatures. Using MTT assay to detect the cytotoxicity of 14 compounds in BGC-823, HCT-116, Hela, HepG-2 cells. Results: A total of 14 known compounds were isolated from Tujia ethnomedicine Kouziqi and determined as chikusetsusaponin IVa methyl ester (1), chikusetsusaponin IVa butyl ester (2), chikusetsusaponin IV (3), chikusetsusaponin IVa (4), 28-desglucosylchikusetsusaponin IVa (5), oleanolic acid-3-O-β-D-(6'- methylester)-glucuronopyranoside (6), (24R)-majonoside R1 (7), (24R)-pseudoginsinoside F11 (8), (20S)-notoginsinoside-R2 (9), (20S)-ginsenoside Rg2 (10), ginsenoside Rg1 (11), ginsenoside Re (12), ginsenoside Rd (13) and chikusetsusaponin-V methyl ester (14). Among the 14 compounds, compounds 5 and 6 showed dose-dependent cytotoxicity to BGC-823, HCT-116, Hela and HepG-2 cells. Compound 5 had cytotoxicity in BGC-823 and HCT-116 cells with IC50 values of 9.94 and 14.17 μmol/L, respectively. Compound 6 had the best cytotoxicity in HepG-2 cells with IC50 value of 12.70 μmol/L. Conclusion: Compound 6 is isolated from Kouziqi for the first time and its spectral data were reported. The antineoplastic activity of Tujia ethnomedicine Kouziqi is based on the oleanolic acid-type triterpenoid saponins and related to the substituents of C-28, but the mechanism still needs to be deeply studied.