Biological And Molecular Evidences For The Antitumor And Antioxidant Potential Of Quercetin In Vitro

To investigate the protective mechanisms of quercetin in promoting HeLa cell apoptosis and protecting human umbilical vein endothelial cells (HUVECs) from oxidative damage, in this study, MTT test was preformed to observe the inhibition rate of quercetin on HeLa cell proliferation (50.0, 75.0 and 100.0 mu mol/L), and the apoptosis rate was measured with flow cytometry. Western blotting was used to detect the protein expression levels in signaling pathways in quercetin-treated HeLa cells and HUVECs. MTT assay results showed that quercetin could inhibit (P < 0.001) the proliferation of HeLa cells in a time-concentration dependent manner. Apoptosis results showed that quercetin can increase the early and late apoptosis rate (P < 0.001). Western blotting revealed that quercetin can down-regulate BCL-2 expression level (P < 0.05), up-regulate BAX and CASPASE-3 expression level (P < 0.05) in HeLa cells. Flow detection results showed that the number of HUVECs labeled with CD105/CD62E and CD31/CD34 in the oxidation group decreased significantly (P < 0.01), increased significantly (P . 0.001) in the drug group. Quercetin can decrease the expression levels of p16, p53 and p21 significantly (P 0.05). In conclusion, quercetin can promote the apoptosis of HeLa cell by regulating the expression level of CASPASE-3, BCL-2 and BAX; and protect HUVECs against oxidative damage and inhibit the apoptosis by down-regulating p16, p53 and p21.