α-Amylase and α-glucosidase inhibitory effects of Sclerocarya birrea [(A. Rich.) Hochst.] subspecies caffra (Sond) Kokwaro (Anacardiaceae) stem-bark extracts
Inhibition of intestinal α-amylase and α-glucosidase is an important strategy to control post-prandial hyperglycemia associated with type 2 diabetes mellitus. In vitro inhibitory effects of crude Sclerocarya birrea stem bark (SBSB) extracts against human urinary α-amylase and Bacillus steatothermophilus α-glucosidase were studied. Crude SBSB methanolic and acetone extracts inhibited human urinary α-amylase more potently than acarbose. Crude SBSB hexane extract was a strong inhibitor of α-glucosidase and weaker inhibitor of α-amylase. Furthermore, SBSB hexane extract significantly suppressed the rise in postprandial glucose level after oral administration of sucrose but failed to induce similar effects after oral administration of starch and glucose in both normal and diabetic rats. The results of this study suggest that the crude SBSB hexane extract may suppress the rise in postprandial hyperglycemia in vivo in part, through inhibition of alpha glucosidase.
Keywords: Diabetic rats, alloxan, postprandial hyperglycemia, diabetes mellitus.