Effects of Quercetin on Mushroom Tyrosinase and B16-F10 Melanoma Cells
2007; Multidisciplinary Digital Publishing Institute; Volume: 12; Issue: 5 Linguagem: Inglês
10.3390/12051045
ISSN1433-1373
AutoresIsao Kubo, Teruhiko Nitoda, Ken-ichi Nihei,
Tópico(s)Biochemical Analysis and Sensing Techniques
ResumoIn searching for tyrosinase inhibitors from plants using L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate, quercetin was found to be partially oxidized to the corresponding o-quinone under catalysis by mushroom tyrosinase (EC 1.14.18.1). Simultaneously, L-DOPA was also oxidized to dopaquinone and both o-quinones were further oxidized, respectively. The remaining quercetin partially formed adducts with dopaquinone through a Michael type addition. In general, flavonols form adducts with dopaquinone as long as their 3-hydroxyl group is free. Quercetin enhanced melanin production per cell in cultured murine B16-F10 melanoma cells, but this effect may be due in part to melanocytotoxicity. The concentration leading to 50% viable cells lost was established as 20 μM and almost complete lethality was observed at 80 μM.
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