Inhibitory Activity of Aegle marmelos L. (Bael) Leaf Ethanolic Extract Against α-Glucosidase

Abstract

Background: Diabetes Mellitus (DM) is a significant global health problem characterized by hyperglycemia. A key therapeutic strategy for managing postprandial hyperglycemia is the inhibition of the α-glucosidase enzyme, which slows glucose absorption. Objectives: This study was designed to evaluate the in vitro α-glucosidase inhibitory activity of an ethanolic extract derived from Bael (Aegle marmelos L.) leaves. Methods: Bael leaves were dried, processed into simplicia, and subsequently extracted via maceration using 96% ethanol to yield an ethanolic extract. The α-glucosidase inhibitory capacity of the extract was assessed spectrophotometrically using an ELISA reader. The assay quantified the absorbance of p-nitrophenol, the product of the enzymatic reaction with the p-nitrophenyl-α-D-glucopyranoside (PNPG) substrate, at a wavelength of 405 nm. Acarbose was utilized as the positive control. Key findings: Acarbose, at concentrations of 0.2, 0.4, 0.6, 0.8, and 1 ppm, exhibited potent, concentration-dependent inhibition of 39.07%, 44.90%, 51.24%, 56.42%, and 62.81%, respectively. In comparison, the A. marmelos leaf extract, at concentrations of 300, 400, 500, 600, and 700 ppm, yielded inhibition values of 11.67%, 20.70%, 29.73%, 44.65%, and 53.37%. The calculated IC₅₀ value for acarbose was 0.569 µg/mL, whereas the IC₅₀ for the A. marmelos extract was determined to be 667.17 µg/mL  Conclusions: These findings indicate that while acarbose possesses exceptionally potent α-glucosidase inhibitory activity, the ethanolic extract of A. marmelos leaves exhibits very weak inhibitory capacity under the tested conditions.