In vitro study of the inhibitory potentials of cold and hot aqueous extract of Vernonia amygdalina, Calotropis procera, and Persea americana on α-glucosidase

Background: The surge in the incidence of diabetes mellitus has spurred heightened interest on alternative and complementary therapies, particularly those derived from medicinal plants. Objective: To assess the α-glucosidase inhibitory activity of cold and hot aqueous extracts of Vernonia amygdalina (bitter leaf), Calotropis procera (locally known as “bomubomu” leaves), and Persea americana (also known as avocado pear) to explore their medicinal applicability. Method: The leaves of V. amygdalina, C. procera, and the seed of P. americana were subjected to cold and hot extraction methods using distilled water. These extracts were specifically targeted for their potential inhibitory effects on α-glucosidase activity, a key enzyme involved in carbohydrate digestion. Results: The α-glucosidase inhibitory assay showed that the extracts from the plants had maximum inhibitory effects at 20 mg/mL. Cold and hot aqueous extracts of V. amygdalina exhibited maximal inhibitory activities of 100% and 86%, respectively, at 20mg/mL. Cold and hot aqueous extracts of C. procera displayed 100% and 91% inhibitory activities, respectively, at 20mg/mL. Similarly, cold and hot extracts of P. americana exhibited the highest inhibitory activities of 77% and 63%, respectively, at 20mg/mL concentration. Conclusions: The findings demonstrated that cold and hot aqueous extracts of Vernonia amygdalina, Calotropis procera, and Persea americana exhibited significant inhibitory activities against α-glucosidase. The observed inhibitory effects suggest the therapeutic potential of these plant extracts as natural remedies for managing post-prandial hyperglycaemia in Type 2 Diabetes mellitus.