title: Isolation and tyrosinase inhibitory effects of polyphenols from the leaves of persimmon, Diospyros kaki.
abstract: The main polyphenols were isolated from the leaves of six selected persimmon cultivars. Seven compounds were obtained by reverse-phase HPLC, and their structures were elucidated by multiple NMR measurements. These compounds are hyperoside, isoquercitrin, trifolin, astragalin, chrysontemin, quercetin-3-O-(2''-O-galloyl-β-D-glucopyranoside) (QOG), and kaempferol-3-O-(2''-O-galloyl-β-D-glucopyranoside) (KOG). Their inhibitory activity was tested against tyrosinase for the oxidation of L-DOPA, and only chrysontemin showed inhibitory activity. To investigate the differences of their inhibitory effects, the tyrosinase inhibitory activities of their aglycons, cyanidin, quercetin, and kaempferol, were also tested. As a result, it was confirmed that the most influential moiety for tyrosinase inhibition was the 3',4'-dihydroxy groups of the catechol moiety. Moreover, the tyrosinase inhibitory activity of chrysontemin, which was identified in persimmon leaves for the first time, is supported by a simulated model of chrysontemin docking into mushroom tyrosinase.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: You-Lin
authors.initials: YL
authors.lastname: Xue
authors.forename: Takuya
authors.initials: T
authors.lastname: Miyakawa
authors.forename: Yasuna
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Okamoto
authors.forename: Fangyu
authors.initials: F
authors.lastname: Hu
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Mitani
authors.forename: Kazuo
authors.initials: K
authors.lastname: Furihata
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Sawano
authors.forename: Masaru
authors.initials: M
authors.lastname: Tanokura
mesh_terms: D000363:Agaricales / Q000201:enzymology; D029788:Diospyros / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D005419:Flavonoids / Q000302:isolation & purification* / Q000494:pharmacology*; D005656:Fungal Proteins / Q000032:analysis / Q000037:antagonists & inhibitors; D014442:Monophenol Monooxygenase / Q000032:analysis / Q000037:antagonists & inhibitors; D010636:Phenols / Q000302:isolation & purification* / Q000494:pharmacology*; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D059808:Polyphenols
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D005656:Fungal Proteins; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D014442:Monophenol Monooxygenase