[Effect of different vitamin E homologous analogues on human hepatoma cell HepG2 proliferation in vitro]

To examine the effect of alpha-tocopherol(alpha-T), gamma-tocopherol(gamma-T), delta-tocopherol(delta-T), and vitamin E succinate (VES) on the proliferation of human hepatoma cell (HepG2), cell proliferation was detected by hemocytometer count, MTT assay and flow cytometry (FCM) with different VE homologues analogues (alpha-T, gamma-T, delta-T and VES) and different concentrations (12.5 mg/L, 25 mg/L, 50 mg/L, 100 mg/L and 200 mg/L). The results showed that The growth of HepG2 cells was inhibited by delta-T and VES at the dosages of 12.5-200 mg/L in comparison with the negative control group, while gamma-T showed weak effect of inhibition and alpha-T did not show any inhibition effect. The dose range to produce inhibition effects varied with different analogues. A dose-dependent inhibition of cell growth was found in HepG2 cell lines treated with different vitamin E homologues analogues. An accumulation of cells in G0/G1-phase and a significant decreasing of cells in S-phase were found as evaluated by flow cytometric analysis employing a PI-staining method. It is suggested that delta-tocopherol and VES decreased HepG2 cells growth and viability. A dose-dependent of anti-proliferation was found in HepG2 cells line. the order of efficiency of four vitamin E analogues was delta-tocopherol > VES > gamma-tocopherol > alpha-tocopherol. The proliferation was blocked in S-phase. The difference in nature and magnitude of the anticancer effects does not correlate with their reported relative antioxidant activity and might be due to minor differences in their structure important to their biological activities. These results suggest that delta-tocopherol and VES could be promising anti-hepatoma agents.