title: Inhibition of tyrosinase by green tea components.
abstract: The pigment melanin in human skin is a major defense mechanism against ultraviolet light of the sun, but darkened skin color, which is the result of increased and redistributed epidermal melanin, could be a serious aesthetic problem. Epidemiologically, it is well known that the consumption of green tea may help prevent cancers in humans and also reduce several free radicals including peroxynitrite. In the present study, to assess the efficacy of the inhibition of mushroom tyrosinase (monophenol monooxygenase EC 1.14.18.1), ten kinds of Korean traditional teas were screened for their tyrosinase inhibitory activity. Green tea was the strongest inhibitor, and the major active constituents in the tea are (-)-epicatechin 3-O-gallate (ECG), (-)-gallocatechin 3-O-gallate (GCG), and (-)-epigallocatechin 3-O-gallate (EGCG). All are catechins with gallic acid group as an active site. The kinetic analysis for inhibition of tyrosinase revealed a competitive nature of GCG with this enzyme for the L-tyrosine binding at the active site of tyrosinase.
authors.affiliation: College of Pharmacy, Research Institute of Drug Development, Pusan National University, Kumjung-Gu, Korea.
authors.forename: J K
authors.initials: JK
authors.lastname: No
authors.forename: D Y
authors.initials: DY
authors.lastname: Soung
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: K H
authors.initials: KH
authors.lastname: Shim
authors.forename: Y S
authors.initials: YS
authors.lastname: Jun
authors.forename: S H
authors.initials: SH
authors.lastname: Rhee
authors.forename: T
authors.initials: T
authors.lastname: Yokozawa
authors.forename: H Y
authors.initials: HY
authors.lastname: Chung
mesh_terms: D000363:Agaricales / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000737:chemistry*; D007700:Kinetics; D007723:Korea; D007980:Levodopa / Q000737:chemistry; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010936:Plant Extracts / Q000737:chemistry; D013662:Tea / Q000737:chemistry*; D014443:Tyrosine / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D010936:Plant Extracts; D013662:Tea; D014443:Tyrosine; D007980:Levodopa; D014442:Monophenol Monooxygenase