Natural compounds have tremendous potential to regulate glucose metabolism, but conventional methods for studying their bioactivities are usually labor intensive. Here, hypoglycemic properties in 22 selected food-derived compounds were examined using molecular docking. The results indicated that curcumin is an inhibitor of both α-glucosidase and dipeptidyl-peptidase 4 (DPP-4), which are important for glycemic control. These effects of curcumin were also confirmed by enzymatic determination in vitro. Furthermore, curcumin significantly improved diet-induced hyperglycemia (e.g., fasting plasma glucose levels and glycogen storage in muscle or liver) in mice. This might be attributed to its inhibitory effects on the activities of α-glucosidase and DPP-4 in vivo. Curcumin also upregulated the expression of genes (e.g., glucagon-like peptide 1) related to DPP-4 activity in the small intestine. In conclusion, curcumin is a potential ingredient of functional foods used for diet-induced hyperglycemia management. PRACTICAL APPLICATIONS: Curcumin has been widely used as a colorant in the food industry. Moreover, a growing number of studies have described its diverse biological functions, such as anti-inflammatory, anti-oxidant, and anti-angiogenic activities. Thus, curcumin is regarded as a potential ingredient in functional foods. Our results highlighted the hyperglycemic effect of curcumin, suggesting that curcumin may be included in food products for hyperglycemic patients.
Keywords: curcumin; dipeptidyl-peptidase 4; hyperglycemia; molecular docking; α-glucosidase.
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