A therapy with natural antioxidants to support the endogenous antioxidant defense system could best protect more effectively to oxydative stress and cancer. This work aims to extract and characterize the major components of Prosopis africana first, to evaluate the antioxidant activity of compounds. The method applied to measure the antioxidant activity was the free radical scavenging by using DPPH• and ABTS•+. Ethanolic and aqueous extracts inhibited the absorbance of DPPH and ABTS radical depending on the different concentrations of each solution. The calculated IC50 are 0.97; 2.28; 2.56 and 20.83μg/ml for the quercetin, the ascorbic acid, the ethanol and aqueous extracts respectively. The phytochemical revealed that extracts contained alkaloids salts, saponins, tannins and flavonoids. Prosopis africana can be considered as an antioxidant plant.