8-hydroxydaidzein, an aldose reductase inhibitor from okara fermented with Aspergillus sp HK-388

The aldose reductase (AR) inhibitor, 8-hydroxydaidzein, was isolated and identified from a methanolic extract of okara (soybean pulp) fermented with the fungal strain, Aspergillus sp. HK-388. 8-Hydroxydaidzein showed non-competitive inhibition of human recombinant AR with respect to DL-glyceraldehyde, its K-i value being evaluated as 7.0 mum.