Evaluation of the acute toxicity and antidiabetic activity of Coutoubea spicata "nicolau" ethanolic extract and ethyl acetate fraction

In order to understand antidiabetic potential and toxicity, this study aimed to evaluate the acute toxicity and antidiabetic activity of ethanolic extract and ethyl acetate fraction obtained from Coutoubea spicata "nicolau" shoots. Chemical constituents and acute toxicity were investigated. In alloxan-induced diabetic rats, extract and fraction were tested at dose of 100 mg/kg, p.o. Body weight gain, glucose, lipid profile and oxidative stress markers in serum and tissues were determined. In vitro antioxidant activity was performed. Swertiamarin, gentiopicrin, deoxyloganic acid, clovin and robinin, and their p-coumaric ester were identified. Extract and fraction were classified as safe (category 5). In diabetic rats, Coutoubea spicata reduced glycaemia, which was accompanied by body weight recovery gain and attenuation in oxidative stress markers. Fraction showed scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical (ABTS) radicals and reducing power higher than that of the extract. Extract and fraction of Coutoubea spicata didn't present significant toxicity and it can be investigated as a therapeutic alternative in diabetes.