In-vitro α-amylase and α-glucosidase inhibitory activity of Adiantum caudatum Linn. and Celosia argentea Linn. extracts and fractions

Objective: The objective of the present study was to provide an in-vitro evidence for the potential inhibitory activity of extracts and fractions of Adiantum caudatum Linn. and Celosia argentea Linn. on alpha-amylase and alpha-glucosidase enzymes. Materials and Methods: The plant extracts were prepared, first with cold maceration (70% v/v ethanol) and then by Soxhlation techniques (95% v/v ethanol). Subsequently, the combined extracts were subjected for fractionation. Different concentrations (0.1, 0.2, 0.3, 0.4, and 0.5 mg/ml) of extract and fractions were subjected to alpha-amylase and alpha-glucosidase inhibitory assay. The absorbance was measured at 540 and 405 nm using multiplate reader and the percentage of alpha-amylase and alpha-glucosidase inhibitory activity and IC50 values of extract and fractions were calculated. Results: Fraction 2 of A. caudatum and fraction 4 of C. argentea has shown highest alpha-amylase and alpha-glucosidase inhibitory potential with IC50 values of 0.241, 0.211 and 0.294, 0.249 mg/ml, respectively, which was comparable with acarbose (0.125 and 0.93 mg/ml). Whereas, extracts and remaining fractions of both the plants have shown lesser activity. Conclusion: The results of the present study indicate that, fraction 2 of A. caudatum, rich in triterpenoids and phenolics and fraction 4 of C. argentea, rich in flavonoids, are effective alpha- amylase and alpha-glucosidase inhibitors, which may be helpful to reduce the postprandial glucose levels. Hence, further studies may throw light on the antidiabetic potential of A. caudatum and C. argentea, especially in the management of type 2 diabetes.