NERIUM OLEANDER LINN. IN VITRO ALPHA AMYLASE INHIBITORY POTENTIAL OF STEM AND ROOT EXTRACTS

Abstract

Objective: Extraction and evaluation of the antidiabetic activity of extracts from stem and roots of Nerium oleander (Apocynaceae) Linn.Methods: Stem and roots of N. oleander were collected, dried and extracted by using well-established methods for alkaloids, flavonoids, steroids and crude extracts in polar and non-polar solvents. Evaluation of their antidiabetic activity was done with salivary alpha-amylase and starch as a substrate using chromogenic DNSA (2,4-Di nitro Salicylic Acid) method and Starch-iodine method. All experiments were performed in 3 different sets each in triplicates. The data are expressed as mean±SEM (standard error of the mean).Results: The highest inhibition for stem was found in its free flavonoid extract at the concentration of 1.5 mg/ml, with percent inhibition 48.35±1.36 % and an IC50 value of 1.774 g/ml while in case of root, highest inhibition was obtained at 1.5 mg/ml of pet ether extract, with % inhibition 52±0.40 % and IC50 value 1.583 g/ml and at 1.5 mg/ml of methanol extract, with % inhibition 42.12±1.12 % and an IC50 value 1.729 g/ml. 8 (5 of stem and 3 of root) out of 14 tested extracts have shown good inhibitory potential. Extracts of the stem were found to be more potent than root extracts.Conclusion: Though stem extracts were found to be a more potent hypoglycemic agent than root extracts, however, extracts of both parts have good antidiabetic potential and both might be fruitful in managing the postprandial hyperglycemia.