Tyrosinase inhibitors isolated from the roots of Paeonia suffruticosa

Abstract

The inhibition of mushroom tyrosinase by Paeonia suffruticosa root-derived materials was evaluated. Six tyrosinase inhibitors were isolated by ethanol extraction, n-hexane, ethyl acetate, n-BuOH, and water partition, silica gel column chromatography, Sephadex LH-20, Lobar PR-8, and high-performance liquid chromatography methods, and they were identified as kaempferol (I), quercetin (II), mudanpioside B (III), benzoyloxypaeoniflorin (IV), mudanpioside H (V), and pentagalloyl-β-D-glucose (VI) on the basis of spectroscopic evidence. The inhibitory activities of compounds I to VI against mushroom tyrosinase were determined with IC 50 values of 0.120, 0.108, 0.368, 0.453, 0.324, and 0.063 mM, respectively. The kinetic study indicated that all purified inhibitors acted competitively for the L-dopa binding site of the enzyme, with an exception of compound VI, which acted non-competitively.