title: Kinobeon A as a potent tyrosinase inhibitor from cell culture of safflower: in vitro comparisons of kinobeon A with other putative inhibitors.
abstract: Kinobeon A is produced from cell cultures of the medicinal plant, safflower. Mushroom tyrosinase activity was inhibited in a concentration-dependent manner when treated with kinobeon A using L-tyrosine or L-3,4-dihydroxyphenylalannine (L-DOPA) as substrates. IC50 values were 22 microM (substrate: L-tyrosine) and 27 microM (L-DOPA). Inhibition of human tyrosinase activity also increased with increasing concentrations of kinobeon A using L-DOPA as the substrate, with an IC50 value of 2.5 microM. Kinobeon A was a more potent competitive inhibitor than kojic acid, arbutin or L-ascorbic acid for both mushroom and human tyrosinase as determined from Lineweaver-Burk plots. These results suggested that kinobeon A could be a potent natural tyrosinase inhibitor.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kanehira
authors.forename: Susumu
authors.initials: S
authors.lastname: Takekoshi
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Nagata
authors.forename: R Yoshiyuki
authors.initials: RY
authors.lastname: Osamura
authors.forename: Takao
authors.initials: T
authors.lastname: Homma
mesh_terms: D000363:Agaricales / Q000201:enzymology; D000475:Alkenes / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D001104:Arbutin / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D031187:Carthamus tinctorius; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020128:Inhibitory Concentration 50; D007980:Levodopa; D014442:Monophenol Monooxygenase / Q000187:drug effects; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D008517:Phytotherapy; D011753:Pyrones / Q000494:pharmacology
chemical_list: D000475:Alkenes; D010455:Peptides; D011753:Pyrones; C477467:kinobeon A; D007980:Levodopa; C011890:kojic acid; D001104:Arbutin; D014442:Monophenol Monooxygenase; D001205:Ascorbic Acid