In-vitro α-amylase and α-glucosidase inhibitory activity of apple peel extract (APE)

The present study was to investigate an in-vitro potential inhibitory activity of extracts and fractions of Apple peel extract (APE) on α-amylase and α-glucosidase enzymes. The APE were prepared from Lal Ambri (Red Delicious) Apple (Maluspumila), first with cold maceration (70% v/v ethanol) and then by Soxhlation techniques (95% v/v ethanol). Different concentrations (0.1, 0.2, 0.3, 0.4, and 0.5 mg/ml) of extract and fractions were subjected to α-amylase and α-glucosidase inhibitory assay. The absorbance was measured at 540 and 405 nm using multiplate reader and the percentage of α- amylase and α- glucosidase inhibitory activity and IC50 values of extract and fractions were calculated. Acarbose was used as a standard reference drug, which showed α-amylase inhibitory activity with an IC50 value of 0.15 mg/ml and α-glucosidase inhibitory activity with an IC50 value of 0.98 mg/ml. Amongst all, fraction 2 of APE has shown best enzyme inhibitory activity with an IC50 value 0.21 (α-amylase and α-glucosidase) and 0.18 mg/ml respectively which were comparable with that of acarbose. The results of the present study indicate that, fraction 2 of APE, rich in flavonoids and polyphenols, are effective α- amylase and α- glucosidase inhibitors, which may be helpful to reduce the postprandial glucose levels. Hence, further studies may throw light on the antidiabetic potential of APE especially in the management of type 2 diabetes.