Flavonoids from the stem barks of Swintonia griffithii Kurz (Anacadiaceae) and their tyrosinase inhibitory activities

Abstract

From the stem barks of Swintonia Griffithii, six flavonoids: ( )-naringenin (1), (-)-eriodictyol (2), (+)-taxifolin (3), (-)-butin (4), (-)-tustin (5), and 3',4',7-trihydroxyflavone (6) were isolated. Their structures were determined based on the spectroscopic interpretation and compared with those of reported data. In the tyrosinase inhibitory activity test, (+)-taxifolin (3) and 3',4',7-trihydroxyflavone (6) exhibited potent effect with the IC₅₀ values of 20.9 and 56.7 µM, respectively.