Biotransformation of sophoricoside in Fructus sophorae was performed with Schizophyllum commune. Sophoricoside was firstly metabolized to 4',5,7-trihydroxyisoflavone (2), and then to 4',7-dihydroxy-5-methoxyisoflavone (3) and 5,7-dihydroxy-4'-methoxyisoflavone (4) as determined by NMR and MS analyzes. The content of compound (2) was increased by more than 30-fold, and compound (3) is a new product that showed good cytotoxic activity with an IC50 of 12.1 nmol/ml against MCF-7 cells. (C) 2012 Elsevier Ltd. All rights reserved.