In vitro Studies on α-Amylase and α-Glucosidase Inhibitory Activity of Some Bioactive Extracts

Objectives: To investigate the therapeutic effects of methanolic leaf extracts of Lindernia ciliata, Phyllanthus reticulatus and Bambusa vulgaris were evaluated for their effect on α-amylase and α-glucosidase inhibition by using in vitro assays. Methods: Leaves of Lindernia ciliata, Phyllanthus reticulatus and Bambusa vulgaris extracted with methanol and these extracts are concentrated under reduced pressure. The inhibitory effect of these extracts on α-amylase and α-glucosidase inhibitory activities as well as some antioxidant parameters was determined in vitro. Results: The results revealed that these methanolic bioactive extracts inhibited α-amylase and α-glucosidase activities in a dose dependent manner. The plant extracts were used at varying concentrations to ensure which concentration of the extract causes the most inhibition. Among all, Lindernia ciliata has shown the prominent enzyme inhibitory activity (for α-amylase IC50 6.11 mg/ml and for α-glucosidase 6.10 mg/ml) and was well comparable with the standard drug acarbose (for α-amylase IC50 5.03 mg/ml and for α-glucosidase IC50 5.13 mg/ml). Phytochemical analysis of the extracts indicated the presence of alkaloids, flavonoids, steroids/triterpenoids and their glycosides, tannins, coumarins, sterols and fatty alcohols. Further, the total phenolic and total flavonoid contents were estimated. These results substantiate the use of Lindernia ciliata in traditional medicine for the treatment of diabetes by controlling postprandial hyperglycemia. Conclusion: The antioxidant properties and enzyme inhibition could be part of the mechanism by which they are used in the treatment/prevention of type-2 diabetes. These findings suggest that the plants may be a potential source for the development of new oral hypoglycemic agent.