Dichloromethane fraction of Asiasarum heterotropoides induces S phase arrest and apoptosis in KB oral epithelial carcinoma cells.

We investigated the anti-cancer activity and molecular mechanism of dichloromethane fraction (DCM-AH) of ethanolic extract from Asiasarum heterotropoides radix. The KB cancer cells and HEK293 cells were exposed to DCM-AH in the same condition and found the cell viability of KB cell decreased significantly while the HEK293 cell showed a slight reduction. This finding suggested DCM-AH performed an anti-cancer activity in a dose and time dependent manner. As evidence for the DCM-AH inhibited the proliferation via modulating the cell cycle, flow cytometry and Western blot were conducted, it induced cell S phase arrest by upregulation of p21, p53, and cyclin E1 along with the downregulation of cyclin A2 and D1. Besides, it inhibited the proliferation of KB cells by triggering apoptosis, the stimulation of 4μg/mL DCM-AH obviously induced DNA condensation with an apoptotic rate of 31.2%. Undergoing mechanism was detected by Western blot, the upregulated expression of Bax, cleaved caspase-3, and -9 meantime downregulation of Bcl-2 explained it induced apoptosis by the intrinsic pathway.