Highly regioselective hydroxylation of polydatin, a resveratrol glucoside, for one-step synthesis of astringin, a piceatannol glucoside, by P450 BM3.

•A set of CYP102A1 mutants can catalyze regioselective hydroxylation of polydatin.•Major product of polydatin hydroxylation is astringin, a piceatannol glucoside.•An efficient enzymatic synthesis of astringin, a piceatannol glucoside, was developed.