Inhibitory effects of polyphenols isolated from Rhus verniciflua on Aldo-keto reductase family 1 B10.

Aldo-keto reductase family 1 B10 (AKR1B10) is a member of the NADPH-dependent aldo-keto reductase (AKR) superfamily, and has been considered to be a potential cancer therapeutic target. Total extract from the bark of Rhus verniciflua (Toxicodendron vernicifluum (Stokes)) showed AKR1B10 inhibitory activity. To identify the active compounds from R. verniciflua responsible for AKR1B10 inhibition, nine compounds were isolated via bioactivity-guided isolation and tested for their effects against recombinant human AKR1B10 (rhAKR1B10). Results showed that butein, isolated from the ethyl acetate fraction, was most able to inhibit rhAKR1B10. The inhibitory rate of butein against rhAKR1B10 was 42.86% at 1 microM with an IC(50) value of 1.47 microM, and enzyme kinetic analysis revealed its inhibition mode to be uncompetitive.