Polyphenols displaying tyrosinase inhibition from the seed of psoralea corylifolia

Abstract

Three chalcones and two flavanones displaying tyrosinase inhibitory activity were isolated from the seed of Psoralea corylifolia, a cultivated edible plant. The isolated compounds were elucidated as known isovabachalcone, 4'-O-methylbavachalcone, isobavachromene, corylifolin, and bavachinin. The inhibitory potencies of the polyphenols toward monophenolase activity of mushroom tyrosinase were investigated. The inhibitory concentration (IC50) values of compounds 1-5 for monophenolase activity were determined to be 12.3, 48.8, 15.8, 23.6, and 143.9 μM, respectively. The potent inhibitors 1-4 exhibited the competitive inhibition characteristics in analysis of Lineweaver-Burks and Dixon-plot.