Effect of gamma irradiation on the anti-oxidant and anti-melanogenic activity of black ginseng extract in B16F10 melanoma cells

Black ginseng extract (BGE) was irradiated at various doses (10, 30, 50, 70, and 100 kGy) to improve its biological activity. The content of reducing sugar was significantly increased by gamma irradiation up to 100 kGy. The gamma-irradiated BGE showed its highest anti-oxidant activity (DPPH radical scavenging activity-IC50 = 4.33 µg, ABTS radical scavenging activity-IC50 = 2.39 µg, FRAP AEAC = 6.46), and mushroom tyrosinase inhibition activity (IC50 = 12.46 mg) when irradiated at the dose of 100 kGy. The gamma-irradiated BGE showed a greater inhibitory effect on IBMX-induced melanin synthesis (121.43%), intracellular tyrosinase activity (91.80%), melanogenic enzyme expression (tyrosinase, TRP-1, and TRP-2), as well as H2O2-induced reactive oxygen species production, than was observed with the non-irradiated BGE-treated group (melanin synthesis-146.21% and intracellular tyrosinase activity-117.11%) in B16F10 melanoma cells without cytotoxicity. In addition, we also found that the anti-melanogenic effect of gamma-irradiated BGE is mediated by the cyclic AMP (cAMP) signaling pathway (MITF and CREB), ERK, and p38 MAPK signaling pathway. Our findings suggest that gamma-irradiated BGE could be a potential anti-melanogenic agent for use in skin-whitening cosmetics. Consequently, gamma irradiation could become an effective tool for developing functional foods and cosmetics.