Evaluation of Alpha-Amylase and Alpha-Glucosidase Inhibitory Activities of Shilajit

Shilajit is considered as a panacea in Ayurveda, as it is effective in number of ailments including diabetes. In the present study, 2 extracts namely, aqueous and ethanol of Shialjit were evaluated for their effect on alpha-amylase and alpha-glucosidase enzymes using in vitro assays. Alpha-Amylase inhibitory activity of Shilajit extracts was evaluated using Porcine pancreatic alpha-amylase (PPA) with starch as a substrate, whereas, alpha-glucosidase inhibitory activity was evaluated using p-nitrophenyl-?-D-Glucopyranoside (PNPG) as a substrate. Further, the antioxidant activity of extracts was monitored using DPPH assay, whereas, phenolic content was estimated using Folin-Ciocalteu reagent. Ethanol extract showed the highest inhibitory activity against alpha-amylase (IC50= 95.05 µg/ml) as well as alpha-glucosidase (IC50= 1.87 µg/ml) than aqueous extract. Both the extracts were strong inhibitors of alpha-glucosidase than alpha-amylase and inhibited the enzyme more potently than the standard acarbose. The alpha-amylase and alpha-glucosidase inhibitory activities of Shilajit correlated to antioxidant activity and phenolic content of extracts. Thus Shilajit can be effective in treatment of diabetes not only through inhibition of alpha-amylase and alpha-glucosidase enzymes, but also by its antioxidant effect.