| Summary: | 碩士 === 國立臺南大學 === 生物科技學系碩士班 === 102 === Melanogenesis inhibition by the methanol layer of Dioscorea nipponica Makino extract (DNM) was investigated both in vitro in cultivated murine B16 melanoma cells and in vivo in zebrafish and mice. In B16 cells, results showed that DNM dose-dependently inhibited melanogenesis under nontoxic concentrations. Despite the potent inhibition of melanogenesis, results from evaluating intracellular tyrosinase activity and tyrosinase zomographic staining showed that DNM did not reduce intracellular tyrosinase activity and the active protein amount of intracellular tyrosinase in B16 cells.However, DNM showed strong antioxidant activities against cell-free DPPH and ABTS+ free radical and intracellular Reactive oxygen species (ROS).
These results reveal that DNM inhibits melanogenesis of B16 cells through antioxidant activity but not through inhibiting tyrosinase activity. The melanogenesis inhibitory activity of DNM was also evaluated in vivo in zebrafish and mice. In zebrafish, melanogenesis of larvae skin was significantly and dose-dependently inhibited by DNM treatment. In mice, application of a 2 % gel preparation of DNM applied to mouse skin slightly increased the degree of skin whitening after 2 weeks of treatment. Based on our findings reported here, DNM is a good candidate for use as a skin-whitening agent for treating skin hyperpigmentation disorders.
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