title: Screening for tyrosinase inhibitors among extracts of seashore plants and identification of potent inhibitors from Garcinia subelliptica.
abstract: The tyrosinase inhibitory activity of methanol extracts of the leaves of 39 plant species growing on the seashore of Iriomote island (Okinawa, Japan) was investigated. The extracts of Hibiscus tiliaceus, Carex pumila, and Garcinia subelliptica showed potent activity among them. The inhibitors in the extract of Garcinia subelliptica were purified by assay-guided fractionation to give two biflavonoids. These were known compounds (2R,3S-5,7,4',5'',7'',3''',4'''-heptahydroxy flavanone[3-8''] flavone and 5,7,4',5'',7'',3''',4'''-heptahydroxy[3-8''] biflavanone), although their strong inhibitory activity toward tyrosinase is revealed for the first time in this work. One of these biflavonoids (2R,3S-5,7,4',5'',7'',3''',4'''-heptahydroxy flavanone[3-8''] flavone) showed much stronger activity (IC50 2.5 microM) than that of kojic acid (IC50 9.1 microM) when L-tyrosine was used as the substrate.
authors.affiliation: Faculty of Integrated Arts and Sciences, University of Tokushima, Tokushima, Japan. masuda@ias.tokushima-u.ac.jp
authors.forename: Toshiya
authors.initials: T
authors.lastname: Masuda
authors.forename: Daiki
authors.initials: D
authors.lastname: Yamashita
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takeda
authors.forename: Shigetomo
authors.initials: S
authors.lastname: Yonemori
mesh_terms: D044950:Flavanones / Q000302:isolation & purification / Q000494:pharmacology*; D047309:Flavones / Q000302:isolation & purification / Q000494:pharmacology*; D029760:Garcinia / Q000737:chemistry*; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010936:Plant Extracts / Q000494:pharmacology
chemical_list: C500251:5,7,4',5'',7'',3''',4'''-heptahydroxy(3-8'')biflavanone; C500250:5,7,4',5'',7'',3''',4'''-heptahydroxyflavanone(3-8'')flavone; D044950:Flavanones; D047309:Flavones; D010936:Plant Extracts; D014442:Monophenol Monooxygenase