Evaluation of the antioxidant and hypoglycaemic potentials of the leaf extracts of stachytarphyta jamaicensis (Verbenaceae)

Abstract

Stachytarpheta jamaicensis (family Verbanaceae) commonly known as blue porterweed is widely used in folk medicine for the treatment of various diseases including diabetes mellitus. The present study investigated the blood glucose lowering effect and the antioxidant activity of the leaf extracts of Stachytarpheta jamaicensis. The phytochemical screening of the powdered leaf sample was done according to standard procedures. The antioxidant activity of the methanol and ethyl acetate extracts of the leaves were investigated using the 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging assay, the total phenolic and flavonoid contents were also evaluated following standard procedures. The hypoglycaemic effect of the extracts was evaluated using streptozotocin-induced diabetes in rats. Phytochemical screening shows the presence of carbohydrates, alkaloids, saponins, tannins, phenolic compounds, and flavonoids. The extracts demonstrated appreciable and concentration-dependent radical scavenging effect with IC50 values of 16.95 µg/mL and 33.12 µg/mL, for the methanol extract and ethyl acetate extract, respectively. Oral administration of the extracts at 200 mg/kg and 400 mg/kg daily dose significant lowers blood glucose levels in streptozotocin-induced diabetes in experimental rats compared to the control group (untreated diabetic animals). The present findings have therefore shown that S. jamaicensis leaves has hypoglycaemic and antioxidant effects and may therefore serve as a potential source of hypoglycaemic agent as well as antioxidant agents for the prevention and management of free radical induced metabolic diseases.