To identify novel inhibitors of tyrosinase, a fluorescent assay was developed which is suitable for high-throughput screening. In the assay, oxidation of the substrate by tyrosinase leads to the release of a fluorescent coumarin. Several small molecules were identified that inhibited mushroom tyrosinase in vitro and human tyrosinase in cell culture. These compounds may represent lead structures...

Tyrosinase is a multifunctional, glycosylated, and copper-containing oxidase, which catalyzes the first two steps in mammalian melanogenesis and is responsible for enzymatic browning reactions in damaged fruits during post-harvest handling and processing. Neither hyperpigmentation in human skin nor enzymatic browning in fruits are desirable. These phenomena have encouraged researchers to seek n...

The enzyme tyrosinase is known to be a multifunctional copper-containing enzyme from the oxidase superfamily, which is the key protein involved in the biosynthesis of the large biological pigment, melanin. The enzyme catalyzes two distinct reactions of melanin biosynthesis, the hydroxylation of a monophenol and the conversion of an o-diphenol to the corresponding o-quinone. Inhibitors of this p...

Tyrosinase (EC 1.14.18.1) plays an indispensable role in the rate-limiting steps of melanin biosynthesis, and its uncontrolled activity may result various diseases, such as albinism, melanoma, freckles, etc. The inhibition tyrosinase provide a useful efficient strategy to treat hyperpigmentation disorders. However, widely used inhibitors, like ?-arbutin, hydroquinone, kojic acid, have many shor...

Tyrosinase is a well-known key enzyme in melanin biosynthesis and its inhibitors have become increasingly important because of their potential use as hypopigmenting agents. In the present study, the anti-melanogenic effect of aqueous and ethanolic extracts from Euphorbia characias leaves, stems, and flowers in cell-free and cellular systems was examined. All the extracts showed inhibitory effec...

Synthesis and biological evaluation of unsymmetrical curcumin analogues (UCAs) have been achieved. Tyrosinase inhibitory activities were found for most of the prepared synthetic UCAs. Among them, compounds containing 4-hydroxyl-substituted phenolic rings with C-2/C-4- or C-3/C-4-dihydroxyl-substituted diphenolic rings were more active (IC(50) = 1.74~16.74 μM) than 4-butylresorcinol and kojic ac...

In therapeutic interventions associated with melanin hyperpigmentation, tyrosinase is regarded as a target enzyme as it catalyzes the rate-limiting steps in mammalian melanogenesis. Since many known agents have been proven to be toxic, there has been increasing impetus to identify alternative tyrosinase inhibitors, especially from natural sources. In this study, we investigated 900 extracts fro...

Many skin-whitening compounds target tyrosinase because it catalyzes two rate-limiting steps in melanin synthesis. Although many tyrosinase inhibitors are currently available for a skin-whitening purpose, undesirable adverse effects are also reported. Thus, numerous efforts have been made to develop safer tyrosinase inhibitors from natural products. In line with this, we tested fifty flavonoids...

Melanogenesis is a biosynthetic pathway for the formation of the pigment melanin in human skin. A key enzyme, tyrosinase, catalyzes the first and only rate-limiting steps in melanogenesis, and the down-regulation of enzyme activity is the most reported method for the inhibition of melanogenesis. Because of the cosmetically important issue of hyperpigmentation, there is a big demand for melanoge...