title: p-coumaric acid not only inhibits human tyrosinase activity in vitro but also melanogenesis in cells exposed to UVB.
abstract: Tyrosinase (TYR) catalyzes rate-limiting steps of melanogenesis and thus its inhibitors are potentially useful as hypopigmenting agents. Recently, p-coumaric acid (p-CA) has been suggested to interfere with the pro-melanogenic actions of tyrosine due to its structural similarity with tyrosine (An SM et al., Br J Dermatol 2008. 159: 292). In this study, we compared the inhibitory effects of p-CA and two other well known TYR inhibitors used in cosmetics--arbutin and kojic acid--on the catalytic activities of mushroom, murine and human TYRs in vitro, using tyrosine and 3,4-dihydroxyphenylalanine (DOPA) as substrates. The results showed that p-CA is a weaker inhibitor of mushroom TYR but much stronger inhibitor of human or murine TYR in comparison with kojic acid and arbutin. In addition, p-CA inhibited human TYR at much lower concentrations than those required for the inhibition of murine or mushroom TYRs. Enzyme kinetics analysis indicated that p-CA is a mixed type (for tyrosine) or competitive inhibitor (for DOPA) of human TYR. Potent antimelanogenic effects of p-CA were observed in human epidermal melanocytes exposed to UVB. The present study demonstrated that p-CA is a potent and selective inhibitor of human TYR and is potentially useful as a hypopigmenting agent.
authors.affiliation: Department of Molecular Medicine and Cell and Matrix Research Institute, BK21 Medical Education Program for Human Resources, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Sang Mi
authors.initials: SM
authors.lastname: An
authors.forename: Jae-Sook
authors.initials: JS
authors.lastname: Koh
authors.forename: Yong Chool
authors.initials: YC
authors.lastname: Boo
mesh_terms: D000363:Agaricales / Q000201:enzymology; D000818:Animals; D001104:Arbutin / Q000494:pharmacology; D002478:Cells, Cultured; D003373:Coumaric Acids / Q000494:pharmacology*; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D000078404:Epidermal Cells; D006801:Humans; D008544:Melanocytes / Q000187:drug effects* / Q000201:enzymology; D008546:Melanoma, Experimental; D051379:Mice; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010858:Pigmentation / Q000187:drug effects; D011422:Propionates; D011753:Pyrones / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D003373:Coumaric Acids; D011422:Propionates; D011753:Pyrones; D014443:Tyrosine; D004295:Dihydroxyphenylalanine; C011890:kojic acid; D001104:Arbutin; D014442:Monophenol Monooxygenase; C495469:p-coumaric acid