Inhibitory effects of compounds from Anemarrhenae Rhizoma on alpha-glucosidase and aldose reductase and its contents by drying conditions

An aqueous extract of Anemarrhena asphodeloides BUNGE (Anemarrhenae Rhizoma) showed inhibitory effects on a-glucosidase and aldose reductase (AR). We obtained two active compounds, mangiferin (alpha-glucosidase: IC50 = 96.1 mu g/ml, AR:IC50 = 0.13 mu g/ml) and mangiferin 7-O-beta-D-glucopyranoside (alpha-glucosidase: IC50 = 158 mu g/ml, AR:IC50 = 65.7 mu g/ ml), from Anemarrhenae Rhizoma. In addition, the amount of mangiferin in Anemarrhenae Rhizoma changed with the method of preparation (drying conditions), namely, low-temperature, long-term drying conditions and harvesting in August were most effective.