Inhibitory compound of tyrosinase activity from the sprout of Polygonum hydropiper L. (Benitade)

A tyrosinase inhibitor was isolated from the sprout of Polygonum hydropiper L. (Benitade) by activity-guided fractionation and identified as (2R,3R)-+-taxifolin (1) by spectroscopic means. Compound 1 inhibited 70% of tyrosinase activity at a concentration of 0.50 mM. ID50 (50% inhibition dose) value of compound 1 was 0.24 mM. As compared with tyrosinase inhibitor known cosmetic agent such as arbutin and kojic acid, compound 1 was more inhibited than the former and showed inhibitory effect equal to that of the latter. To study the inhibitory effect of (2R,3R)-+-taxifolin derivatives against tyrosinase activity, 3,7,3',4'-taxifolin tetraacetate (2) and 5,7,3',4'-taxifolin teramethyl ether (3) were also assayed together with compound 1.