Abstract: To investigate the effect of didymin on apoptosis of human hepatocellular carcinoma HepG2 cells and its action mechanism.MTT assay was used to investigate the effect of didymin on proliferation of HepG2 cells.Flow cytometry assay was used to analyze apoptosis rate of HepG2 cells.The effects of didymin on caspase-3 and caspase-9 activities were detected using available kits.The protein expressions of Bcl-2,Bax,RKIP,ERK and p-ERK were detected by Western blot.The experimental resultsshowedthatdidymin can inhibit HepG2 proliferation and induce cell apoptosis,by activating caspase-3 and 9,regulating Bax andBcl-2 level.Moreover,our study indicated that didyminincreased RKIPexpression,resulting in the inactivation ofERK/MAPK signaling pathways.

Key words: didymin, HepG2 cells, apoptosis, RKIP, ERK/MAPK signaling pathway