Inhibitory effect of glucodistylin from the bark of Quercus acutissima on human recombinant aldose reductase and sorbitol accumulation.

A flavanol glycoside, glucodistylin (1) and three polyphenol derivatives, gallate (2), (+)-catechin (3) and (+)-gallocatechin (4) were isolated from an aqueous acetone extract of the bark of Quercus acutissima. Of these compounds, glucodistylin exhibited uncompetitive inhibitory activity against recombinant human aldose reductase with an IC(50) value of 7.2 μM. Furthermore, glucodistylin inhibited sorbitol accumulation by 48.84% at 50 μM. This flavonoid showed therapeutic potential in the prevention and treatment of diabetes-related complications.