Abstract: Objective: To determine the effect of quercetin and procyanidins on melanogenesis in the guinea pig model of vitiligo. Methods: Thirty eight guinea pig models of vitiligo were successfully induced by perhydrol. The guinea pig models of vitiligo were randomly divided into 5 groups: ethanol (group A), distilled water (group B), 0.1% 8-methoxypsoralen（8-MOP）(group C), 0.5% quercetin (group D), 0.1% proanthocyanidin (group E) and 0.3% proanthocyanidin (group F). The guinea pig models in the group C were given sunlight exposure for ten minutes after taking medicine for 1h. The level of pigmentation on skin lesions in guinea pigs was recorded every 2 weeks. All the animal models were killed and the skin of the tested area was taken after 40 days. The basic pathological changes were observed by naked eyes and HE staining. The cell numbers of melanocyte granules were detected by Fontana-Masson method. Results: There were different degrees of pigmentation in group C-D during treatment. HE staining showed that the thicknesses of skin in group C-D were thicker and the pigmentation was more obvious than that in group A and B. Fontana-Masson method showed that melanin granules in group C-D were significantly more than those in group A and B (Ps < 0.05) and the numbers of melanin granules in group D and F were much more than that in group E (Ps < 0.05 ). Conclusion: Quercetin and procyanidins may increased the pigment in the guinea pig models of vitiligo.

Key words: quercetin, proanthocyanidins, vitiligo, melanocytes