title: Tyrosinase inhibitory effects of 1,3-diphenylpropanes from Broussonetia kazinoki.
abstract: Six 1,3-diphenylpropanes exhibiting inhibitory activities against both the monophenolase and diphenolase actions of tyrosinase were isolated from the methanol (95%) extract of Broussonetia kazinoki. These compounds, 1-6, were identified as kazinol C (1), D (2), F (3), broussonin C (4), kazinol S (5) and kazinol T (6). The latter two species (5 and 6) emerged to be new 1,3-diphenylpropanes which we fully spectroscopically characterized. The IC(50) values of compounds (1, 3-5) for monophenolase inhibition were determined to range between 0.43 and 17.9 microM. Compounds 1 and 3-5 also inhibited diphenolase significantly with IC(50) values of 22.8, 1.7, 0.57, and 26.9 microM, respectively. All four active tyrosinase inhibitors (1, 3-5) were competitive inhibitors. Interestigly they all mainfested simple reversible slow-binding inhibition against diphenolase. The most potent inhibitor, compound 4 diplayed the following kinetic parameters k(3)=0.0993 microM(-1)min(-1), k(4)=0.0048 min(-1), and K(i)(app)=0.0485 microM.
authors.affiliation: Division of Applied Life Science (BK21 program), EB-NCRC, Institute of Agriculture & Life Science, Graduate School of Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Yoon Su
authors.initials: YS
authors.lastname: Baek
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Ryu
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Curtis-Long
authors.forename: Tae Joung
authors.initials: TJ
authors.lastname: Ha
authors.forename: Rajesh
authors.initials: R
authors.lastname: Rengasamy
authors.forename: Min Suk
authors.initials: MS
authors.lastname: Yang
authors.forename: Ki Hun
authors.initials: KH
authors.lastname: Park
mesh_terms: D001555:Benzene Derivatives / Q000494:pharmacology*; D001667:Binding, Competitive; D031623:Broussonetia / Q000737:chemistry*; D045782:Hemiterpenes / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010936:Plant Extracts; D011407:Propane / Q000494:pharmacology*; D012118:Resorcinols / Q000494:pharmacology*
chemical_list: D001555:Benzene Derivatives; D045782:Hemiterpenes; D010936:Plant Extracts; D012118:Resorcinols; C000599716:kazinol C; D014442:Monophenol Monooxygenase; D011407:Propane