title: Tyrosinase inhibitory effects and inhibition mechanisms of nobiletin and hesperidin from citrus peel crude extracts.
abstract: The inhibitory effects of nobiletin and hesperidin from citrus peel crude extracts on tyrosinase diphenolase activity have been evaluated. IC50 of nobiletin and hesperidin were 1.49 mM and 16.08 mM, respectively and their inhibition mechanisms are competitive type with inhibition constant (Ki) 2.82 mM and noncompetitive type with Ki 9.16 mM, respectively. Crude extracts from citrus peel (C. unshiu Marc.) were extracted with 95% ethanol and fractionated by petroleum ether (PCPE). The ethanol phase (ECPE) was further desorbed from macroporous adsorption resin (FGRE). Their IC50 values were 8.09 mg/mL, 7.53 mg/mL and 4.80 mg/mL, respectively. Their inhibition of melanogenesis in B16 mouse melanoma cells was also evaluated. FGRE showed a significant inhibition (42.48% at 31.25 microg/mL, p < 0.01) while hesperidin showed almost no inhibition. Nobiletin and PCPE gave efficacious antiproliferation effects on the B16 mouse melanoma cell with IC50 values 88.6 microM and 62.96 microg/mL, respectively, through the MTT test. Hesperidin and other crude extracts showed very low cytotoxity to the B16 cell.
authors: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, China.
authors: Chongwei
authors: C
authors: Zhang
authors: Yanhua
authors: Y
authors: Lu
authors: Lin
authors: L
authors: Tao
authors: Xinyi
authors: X
authors: Tao
authors: Xiaochun
authors: X
authors: Su
authors: Dongzhi
authors: D
authors: Wei
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002957:Citrus / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D047309:Flavones / Q000302:isolation & purification / Q000494:pharmacology*; D006569:Hesperidin / Q000302:isolation & purification / Q000494:pharmacology*; D008543:Melanins / Q000378:metabolism; D008546:Melanoma, Experimental / Q000378:metabolism / Q000473:pathology; D051379:Mice; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010936:Plant Extracts / Q000737:chemistry*; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D047309:Flavones; D008543:Melanins; D010936:Plant Extracts; C008661:nobiletin; D006569:Hesperidin; D014442:Monophenol Monooxygenase