Inhibition of melanin formation by kojic acid derivative KAD3
【摘要】：Melanogenesis is the process of producing melanin pigments that are responsible for the color of skin, eyes and hair and provide protection from ultraviolet radiation. However, excessive levels of melanin formation can lead to pigmentation disorders such as freckles, melasma and age spots, in which tyrosinase plays an important role. Kojic acid was well known by its de-pigmenting activity, however it has been banned to use in cosmetic due to its instability and side effect. In this study, a novel kojic acid derivative KAD3(5-hydroxy-2-(((4-(((1 Z,2 Z)-3-phenylallylidene)amino)-5-(2-((E)-3-phenylallylidene)hydrazinyl)-4 H-1,2,4-triazol-3-yl)thio)methyl)-4 H-pyran-4-one) was synthesized, which molecular weight is 498. The inhibitory mechanism of KAD3 on melanin formation was evaluated by enzyme assay, cell assay and zebrafish assay. The results showed that KAD3 could effectively inhibit the diphenolase activity of mushroom tyrosinase with IC50 of 10.00 μmol/L and it belongs to revisible mixed inhibitor. Then, the antimelanogenic activity of KAD3 was further confirmed by assessing the inhibition of melanin content and intracellular tyrosinase activity in B16 F10 cells and zebrafish model. It demonstrated that KAD3 suppressed the expression of microphthalmia-associated transcription factor(MITF), tyrosinase(TYR), tyrosinase related protein-1 and 2(TRP-1 and TRP-2) in a concentration-dependent manner. Otherwise, we found KAD3 could inhibit the pigment formation of zebrafish embryo and the effect stronger than kojic acid. Our study could lay the theoretical foundation for the application of kojic acid derivatives in the fields of cosmetics and medicine and provide new ideas for the development of new anti-melanogenesis agents.