Reactive oxygen species production is involved in quercetin-induced apoptosis in human hepatoma cells

Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality in Asia. The aim of this study was to examine whether reactive oxygen species production is involved in quercetin-induced apoptosis in human HCC cell lines. Quercetin inhibited the growth of hepatoma cells in dose and time dependent manners. Quercetin treatment of hepatoma cells resulted in changes of cell cycle progression. The G0/G1 phase was decreased and S phase was increased in HA22T/VGH cells after treatment with quercetin. The levels of apoptotic sub-G0/G1, reactive oxygen species and annexin V were increased prior to cell death and concurrent with lipid peroxidation in two human hepatoma cells after treatment with quercetin. Quercetin also enhanced the apoptotic effect of the chemotherapeutic agent, paclitaxel, in HA22T/VGH cells. Quercetin has therapeutic potential as an anti-cancer drug. These results provide basis for further study into the potential use of quercetin in combination with paclitaxel for treatment of hepatoma.