| Summary: | 碩士 === 中國醫藥大學 === 藥學系碩士班 === 101 === Melanin is formed through a series of oxidation and polymerization reactions, which were regulated by tyosinase. Many researches revealed that inhibition of tyrosinase can reduce melanogenesis. In creatures, melanin was classified into eumelanin and pheomelanin which exist as mixture. And evidences show that increase pheomelanin or decrease eumelanin can produce whitening effect. In this study, we would like to investigate whether hyaluronic acid containing gold nanoparticles (HA-AU NPs) and sclareol would inhibit the formation of melanin. In MTT assay, IC20 of HA-AU NPs and sclareol was 15 ppm and 25 μM respectively. Moreover, HA-AU NPs and sclareol can obviously attenuate mushroom tyrosinase activity. Then in vitro assay, HA-AU NPs and sclareol can suppress melanogenesis which stimulated by α-melanocyte stimulating hormone (α-MSH). However, in murine tyrosinase assay, HA-AU NPs showed no significant inhibition effect compared with sclareol.
Furthermore, we want to identify whether combination of HA-AU NPs and sclareol could enhance inhibition of melanogenesis. The results demonstrated that combination use (5 ppm HA-AU NPs and 10 μM sclareol) can improve inhibition effect. Finally, we also revealed that sclareol (25 μM) and combination use (5 ppm HA-AU NPs and 10 μM sclareol) can inhibit melanogenesis via phosphorylation of ERK and p38, but the mechanism of HA-AU NPs is still unclear. Then in vivo assay, HA-AU NPs (50 ppm) and sclareol (50 μM) can inhibit mice tyrosinase and melanogenesis which stimulated by UVB irradiation. According to our study HA-AU NPs and sclareol may be potential agents on whitening cosmetics.
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