Evaluation of Traditional Indian Antidiabetic Medicinal Plants for Human Pancreatic Amylase Inhibitory EffectIn Vitro

Abstract

Pancreaticα-amylase inhibitors offer an effective strategy to lower the levels of post prandial hyperglycemia via control of starch breakdown. Eleven Ayurvedic Indian medicinal plants with known hypoglycemic properties were subjected to sequential solvent extraction and tested forα-amylase inhibition, in order to assess and evaluate their inhibitory potential on pancreaticα-amylase. Analysis of 91 extracts, showed that 10 exhibited strong Human Pancreatic Amylase (HPA) inhibitory potential. Of these, 6 extracts showed concentration dependent inhibition withIC50values, namely, cold and hot water extracts fromFicus bengalensisbark (4.4 and 125 μgmL-1),Syzygium cuminiseeds (42.1 and 4.1 μgmL-1), isopropanol extracts ofCinnamomum verumleaves (1.0 μgmL-1) andCurcuma longarhizome (0.16 μgmL-1). The other 4 extracts exhibited concentration independent inhibition, namely, methanol extract ofBixa orellanaleaves (49 μgmL-1), isopropanol extract fromMurraya koenigiileaves (127 μgmL-1), acetone extracts fromC. longarhizome (7.4 μgmL-1) andTribulus terrestrisseeds (511 μgmL-1). Thus, the probable mechanism of action of the above fractions is due to their inhibitory action on HPA, thereby reducing the rate of starch hydrolysis leading to lowered glucose levels. Phytochemical analysis revealed the presence of alkaloids, proteins, tannins, cardiac glycosides, flavonoids, saponins and steroids as probable inhibitory compounds.