Inhibitory effects of luteolin isolated from Ixeris sonchifolia Hance on the proliferation of HepG2 human hepatocellular carcinoma cells.

We investigated the anti-proliferative effects of luteolin and apigenin, isolated from Ixeris sonchifolia Hance, on HepG2 human hepatocellular carcinoma cells. In MTT assay luteolin showed more efficient anti-proliferative effects on cells than apigenin did. According to propidium iodide staining and flow cytometry studies, we postulated that these effects might be a result of cell cyde arrest. Hence we examined the changes of protein expressions related to cell cycle arrest. Western blotting data demonstrated that the down-regulated expression of CDK4 was correlated to the increase of p53 and CDK inhibitor p21(WAF1/CIP1) protein. These data suggest that luteolin may have potential as an anti-cancer agent.