Mechanism of inhibition of melanogenesis by hydroquinone.

摘要: Hydroquinone (HQ) is one of the most effective inhibitors melanogenesis in vitro and vivo, widely used for treatment melanosis other hyperpigmentary disorders. In an attempt to get some insight into molecular mechanism depigmenting action, which still very poorly understood, we have investigated effect HQ on tyrosinase catalysed conversion tyrosine melanin. Incubation 0.5 mM with 0.07 U/ml phosphate buffer at pH 6.8 presence led no detectable melanin formation, due preferential oxidation respect (HPLC evidence). Kinetic investigations showed that a poorer substrate than tyrosine; yet, it may be effectively oxidised owing generation catalytic amounts dopa acting as cofactor tyrosinase. Product analysis predominant formation early stages hydroxybenzoquinone (HBQ), arising from enzymic hydroxylation subsequent HQ, along lower benzoquinone (BQ). These results suggest activity partly related ability compound act alternate tyrosinase, thereby competing active melanocytes.