Effect of drying methods and extraction solvents on anti-amylase activity of selected medicinal plants

Abstract

Presently, there is a blooming recognition in using the herbal medicine to treat the Diabetic mellitus due to the negative side effects of usage in synthetic drugs. The present study was aimed to evaluate the potential of anti-amylase activity of three different leaf extracts of Thebu (Costus speciosus), Kowakka (Coccinia grandis) and Masbadda (Gymnema sylvestre) following different drying techniques i.e; shade drying at room temperature, oven drying at 45 oC and freeze drying. Dried plant leaves were macerated with n-hexane, ethyl acetate and ethanol for 24 hours at room temperature separately. Obtained extracts were used to determine the anti- amylase activity. Results revealed that freeze dried ethanolic leaf extracts of all selected species showed the highest anti- amylase activity compared to the other drying methods. Further, there was a significant effect (p <0.05) on the drying techniques and solvents used to extract in inhibition of alpha amylase activity. Freeze dried C. speciosus and C. grandis ethanolic extracts displayed an effective inhibition against alpha amylase with an IC50 value of 4 mg/ml and 4.16 mg/ml respectively. Therefore, this study revealed that the drying methods significantly affected on the inhibition of alpha amylase enzyme. Freeze-drying was the most promising drying method and ethanol was the best solvent in extracting anti-amylase bioactive compounds from leaf extract of C. speciosus, C. grandis and G. sylvestre.