Effect of quercetin on postprandial glucose excursion after mono- and disaccharides challenge in normal and diabetic rats

Postprandial hyperglycemia is a major risk factor for diabetic complications leading to disabilities and mortality in diabetics. Quercetin, a flavonoid, has been tried in traditional medicine for treating diabetes. The present study was designed to evaluate the potential of quercetin to control postprandial blood glucose level after maltose and glucose loading in normal and STZ-induced diabetic rats. Normal male Albino wistar rats and STZ-induced diabetic rats were treated with 300 and 600 mg/kg quercetin orally to evaluate the effect on postprandial hyperglycemia after carbohydrate loading, using acarbose as comparator. The results clearly showed ameliorated postprandial hyperglycemia due to the use of quercetin (300 and 600 mg/kg), it significantly dampened the postprandial hyperglycemia by 32.0% and 64.0% respectively, in maltose loaded diabetic rats, and 30.3% after 300 mg/kg dose in normal rats, compared to control; while acarbose produced 51% and 54% decrease in this respect in the two models respecttively. Quercetin in 600 mg/kg dose produces significantly more reduction in postprandial hyperglycemia compared to acarbose, while in rats that received glucose and quercetin, postprandial hyperglycemia was not significantly affected. In conclusion, quercetin effectively suppresses postprandial hyperglycemia in STZ-induced diabetic rats loaded with maltose, which may be attributed to α-glucosidase inhibition. Quercetin could be used as a potential supplement for treating postprandial hyperglycemia.