Cimicifugafoetida extract inhibits proliferation of hepatocellular cells via induction of cell cycle arrest and apoptosis

The purpose of this study is to determine whether the ethyl acetate fraction (EAF) from the aerial part of Cimicifuga foetida Linnaeus possesses the anti-tumor action on hepatoma, and therefore, provide evidence for the traditional use of the plant as a detoxification agent. EAF was extracted and its cytotoxicity was evaluated on a panel of Hepatocytes by MTT assay. The IC50 values of EAF on HepG2, R-HepG2 and primary cultured normal mouse hepatocytes were 21, 43 and 80 μg/mL, respectively. Morphology observation, Annexin V-FITC/PI staining, cell cycle analysis and western blot were used to further elucidate the cytotoxic mechanism of EAF. EAF induced G0/G1cell cycle arrest at lower concentration (25 μg/mL), and triggered G2/M arrest and apoptosis at higher concentrations (50 and 100 μg/mL, respectively). An increase in the ratio of Bax/Bcl-2, activation of downstream effector Caspase 3, and cleavage of poly-ADP-ribose polymerase (PARP) were implicated in EAF-induced apoptosis. In addition, EAF inhibited the growth of the implanted mouse H22 tumor in a dose-dependent manner with the growth inhibitory rate of 63.32% at 200 mg/kg. In conclusion, EAF may potentially find use as a new therapy for the treatment of hepatoma.