Abstract: Objective To investigate quercetin′s protective effect against oxidative stress in and impact on the biological activity of mouse B10BR melanocytes. Methods B10BR cells were cultured and treated with different concentrations of quercetin followed by additional culture. Then, cell viability was measured by using MTT assay, hydrogen peroxide-induced cell apoptosis by flow cytometry, and cell morphological changes by microscopy. The tyrosinase activity in and melanin synthesis by B10BR cells were measured by dopa oxidation assay and sodium hydroxide （NaOH）-lysis method, respectively. Results After treatment with quercetin of 33.33 μmol/L for 24 hours, the survival rate of B10BR cells reached （94.22 ± 3.36）%, tyrosinase activity（107.15 ± 10.96）%, and melanin content （111.85 ± 9.49）%. A significant difference was observed in tyrosinase activity and melanin content between hydrogen peroxide-induced and 33.33 μmol/L quercetin-treated B10BR cells and those only induced by hydrogen peroxide （both P < 0.01）. Flow cytometry revealed that quercetin inhibited hydrogen peroxide-induced apoptosis in melanocytes. Conclusion The protective effect of quercetin against hydrogen peroxide-induced apoptosis in melanocytes may provide a new idea for the treatment of vitiligo.

Key words: quercetin, Apoptosis, GSH-Px