Antioxidant Activity and Hepatoprotective Effect of an Aqueous Extract of <i>Alchornea cordifolia</i> Leaves

Abstract

Alchornea cordifolia is a medicinal plant, whose ethanolic and methanolic extracts have shown antioxidant activity which could confer hepatoprotective effect, knowing that liver cells are attacked by free radicals. The hepatoprotective effect of these extracts has been demonstrated in models of hepatotoxicity induced by paracetamol high doses in animals. However, anti-tubercular drugs at the usual dose present hepatotoxicity risk. Could Alchornea cordifolia help to limit hepatotoxicity induced by anti-tubercular drugs? This work aimed to evaluate the antioxidant activity and the hepatoprotective effect of an aqueous extract of A. cordifolia leaves (AEAC). The antioxidant activity of A. cordifolia leaves was studied in vitro by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals scavenging assay and by the iron reduction ability. A phytochemical screening was carried out to identify the chemical groups that could be responsible for this activity. The hepatoprotective effect was demonstrated in a model of hepatotoxicity induced by isoniazid and rifampicin in rats. Two hours after induction of hepatotoxicity, the animals were orally administered the AEAC at 200 mg/kg, 400 mg/kg, 800 mg/kg for 10 consecutive days. A blood sample was taken on the 11 th day for the evaluation of transaminases, markers of hepatic cytolysis. A totally of 96 rats were used in this study. AEAC showed dose-dependent antioxidant activity. Phytochemical screening revealed the presence of flavonoids, tannins and alkaloids. Administrated alone, aqueous extract of A. cordifolia leaves didn’t modificate the transaminases, isoniazid and the isoniazid + rifampicin combination resulted in increasing transaminases (ALT and AST) by more than 48%. AEAC at 800 mg/kg reduced AST and ALT levels by more than 45%. AEAC at 200 mg/kg and 400 mg/kg decreased ALT more than 40%. Knowing that antioxidant activity protects liver, the AEAC may by its antioxidant activity, contribute to protect against the hepatotoxicity induced by anti-tubercular drugs in the rat.