Low-glycemic foods with wheat, barley and herbs (Terminalia chebula, Terminalia bellerica and Emblica officinalis) inhibit α-amylase, α-glucosidase and DPP-IV activity in high fat and low dose streptozotocin-induced diabetic rat.

Wheat, barley or wheat + barley and herbs (Terminalia chebula, Terminalia bellerica and Emblica officinalis) based low-glycemic-index (low-GI) foods were developed and studied α-amylase, α-glucosidase and DPP-IV inhibition property in vitro and in the streptozotocin-induced diabetic rats. The GI of products ranged from 47 to 53 than control white bread (GI = 95). Total phenolic (20.1 ± 1 mg gallic acid/g dry wt.) and flavonoids (15.2 ± 1 mg quercetin/g dry wt.) were higher in wheat + barley than barley (17.2 ± 1; 13.6 ± 2) and wheat (16.9 ± 1; 14.9 ± 2) products. The in vitro α-amylase (4-10%), α-glucosidase (5-17%) and DPP-IV (3-26%) inhibition (IC50) of methanol extracts were higher than the aqueous extracts. The fasting blood glucose (50.85, 33.22 and 24.52%) and oral glucose tolerance (AUC = 32.1, 36.04, and 27.73%) was lower in barley, wheat, and wheat + barley fed diabetic groups than diabetic control group (1571.5 ± 13.5 mg/dL/120 min). Feeding wheat, barley, and W + B foods for 60 days inhibited the intestinal α-amylase (1.2, 1.1 and 1.5-folds), α-glucosidase (1.3, 1.2 and 1.7-folds) and DPP-IV (1.6, 1.5 and 2.1-folds) activity compared to diabetic control. Low-GI foods lower the systemic glucose level, inhibit the glycolytic enzymes and DPP-IV activity and hence desirable for diabetes management. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05231-0.