To clarify a postprandial glucose suppression effect of diacylated anthocyanin with α-glucosidase (AGH) inhibitory activity, a single oral administration study of it in male 8-week-old Sprague-Dawley rats was performed. The diacylated anthocyanin used in this study was peonidin 3-O-[2-O-(6-O-Eferuloyl-β-D-glucopyranosyl)-6-O-E-caffeoyl- β-D-glucopyranoside]-5-O-β-D-glucopyranoside isolated from storage roots of the purple sweet potato (Ipomoea batatas cv. Ayamurasaki), which showed a potent maltase inhibitory activity with an IC50 value of 200 μM preferable to sucrase inhibition. When the diacylated anthocyanin (100 mg/kg) was administered following maltose (2 g/kg), a maximal blood glucose level (BGL) at 30 min was significantly decreased by 16.5% (P < 0.01) compared to vehicle. A minimum 10 mg/kg dose of the anthocyanin was necessary for the suppression of glycemic rise, and the ED20 (69 mg/kg) was estimated to be ∼30-fold lower than that of the therapeutic drug acarbose (ED20 = 2.2 mg/kg). A reduction of serum insulin secretion was also observed corresponding to the decrease in BGL. No significant change in BGL was observed when sucrose or glucose was ingested, suggesting that the anti-hyperglycemic effect of the anthocyanin was achieved by maltase inhibition, not by sucrase or glucose transport inhibition at the intestinal membrane.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)