In vitro α-amylase and α-glucosidase inhibitory effects and cytotoxic activity of Albizia antunesiana extracts

Context: Diabetes mellitus is a chronic disease, and its incidence is tremendously increasing globally. Decreasing postprandial hyperglycemia by retarding glucose absorption through inhibiting carbohydrates digesting enzymes (alpha-amylase and alpha-glucosidase) is one of many approaches used for the management of this disease. Objectives: The leaf and root aqueous and ethanol extracts of Albizia antunesiana were investigated for alpha-amylase and alpha-glucosidase inhibitory and cytotoxic activity in vitro. Materials and Methods: The alpha-amylase and alpha-glucosidase activities were measured in the presence of aqueous and ethanol extracts of the plant parts using starch and p-nitrophenyl-D-glucopyranoside as substrates respectively. Furthermore, cytotoxic effects of the extracts were investigated on HEK (human embryonic kidney) 293 cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. Results: The results showed that ethanolic root extract of A. antunesiana had mild alpha-amylase and strong alpha-glucosidase inhibitory activity with half-maximal inhibitory concentration values of 30.68 and 4.35 mu g/mL, respectively. The aqueous root extract showed mild alpha-glucosidase but no alpha-amylase inhibitory activity. Cytotoxicity studies on the extracts using the MTT assay revealed that the ethanolic (leaf and root) extracts were relatively nontoxic at tested concentrations on the HEK 293 cell lines. However, the aqueous extracts (leaf and root) were cytotoxic at concentrations above 50 mu g/mL. Conclusion: Data from this study suggest that the ethanolic root extract of A. antunesiana possess in vitro alpha-amylase and alpha-glucosidase inhibitory activities and are not cytotoxic at least in an in vitro condition.