Inhibition Effects of Mangosenone F from Garcinia mangostana on Melanin Formation in B16F10 Cells

Abstract

Melanogenesis can be controlled by tyrosinase inhibition or by blocking the maturation processes of tyrosinase and its related proteins. Mangostenone F was isolated from the seedcases of Garcinia mangostana. Mangostenone F Was shown to be inactive against tyrosinase (IC50 > 200 mu M) but was a potent alpha-glucosidase inhibitor in vitro (IC50 = 21.0 mu M). Mangastenone F was found to inhibit production of melanin in the mouse melanoma cell line B16F10. Importantly, unlike. most glycosidase, inhibitors, mangostenone F displayed very low cytotoxicity (EC50 > 200 mu M). The Western blot for expression levels of proteins involved in melanogenesis showed that mangostenone F down-regulated :tyrosinase and TRP-2 expression. Treating B16F10 cells with mangostenone F significantly increased the susceptibility of tyrosinase to endoglycosidase H digestion, indicating that tyrosinase was unable to mature fully and pass to the trans-golgi apparatus. Consistent with these data, in lysate assays, mangosterione F was shown to be a better inhibitor of alpha-glucosidases than deoxynojirimycin, a representative glycosidase inhibitor.