Antioxidant Activity and Inhibition of Carbohydrate Hydrolyzing Enzymes by Underutilized Parts From Some Plant‐Based Foods and Their Effect on Postprandial Hyperglycemia

The present study investigated the in vitro α‐amylase and α‐glucosidase inhibitory activities, antioxidant potential, and in vivo hypoglycemic effects of some underutilized parts of common plant‐based foods. All samples were collected from natural habitat and the byproducts (peels and seeds) were collected after the edible parts were removed. The samples were processed using standard protocol to obtain the extracts. The hypoglycemic activity was conducted on the most promising underutilized parts in high sucrose‐ and maltose‐induced hyperglycemic rats. From the results, pawpaw seed, banana, plantain, and potato peels showed highest α‐amylase and α‐glucosidase inhibition and antioxidant activities with half maximal inhibitory concentration (IC 50 ) values ≤ 100 μg/mL. Among these, banana peel demonstrated the lowest IC 50 values ( p < 0.05). Mode‐of‐inhibition studies revealed noncompetitive inhibition for most samples, except for mixed inhibition observed in potato peel (α‐amylase) and pawpaw seed (α‐glucosidase). The in vivo part, further demonstrated that supplementation of these plant‐based parts, particularly banana peel, significantly ( p < 0.05) reduced postprandial blood glucose levels in high‐sucrose and high‐maltose tolerance tests. The banana‐peel‐treated group showed the lowest area under the glucose tolerance curve (AUC), comparable to the normal control. In conclusion, our data highlight banana peel as the most promising candidate among the tested underutilized plant‐based food parts, capable of mitigating postprandial hyperglycemia through inhibition of carbohydrate‐digesting enzymes and reduction of oxidative stress. Incorporation of banana peel into functional foods could therefore provide a cost‐effective natural strategy for managing metabolic disorders such as type 2 diabetes (T2D).