Evaluation of the Antioxidant Activity of Aqueous and Methanolic Extracts of Various Organs of Alchornea cordifolia by Scavenging the Radical Ion ABTS?+

Alchornea cordifolia is a shrub very widespread in sub-Saharan Africa where it is used in traditional medicine in the treatment of several aliments. Indeed, in vitro and in vivo studies on animal models have demonstrated therapeutic properties such as the antioxidant properties of extracts from A. cordifolia leaves, the antioxidant activity being variable with the extraction solvent. However, the antioxidant activity has not been evaluated on other parts of the plant. The aim of this work is to evaluate the antioxidant activity of different concentrations of aqueous and methanolic extracts of different A. cordifolia organs, namely: leaves, trunk, fruit pulp and stem. The main goal is to determine the most antioxidant organ of the plant and the extraction solvent to observe a better yield in terms of activity. The method is based on the measurement of the free radicals of the radical cation of 2, 2'-azinobis [3-ethylbenzothiazoline-6-sulfonic acid] (ABTS?+) by comparison with that of gallic acid, a reference antioxidant. The results showed on the one hand that the extraction in methanol of the bioactive compounds was superior to the aqueous extraction. In general, the methanolic extracts exhibited better antioxidant activity than the aqueous extracts. On the other hand, we have shown that the leaf is the most active organ followed by the bark of the trunk and the pulp of fruit whose activities are similar. The stem appears to be the least active organ. The IC50 values are as follows; methanolic extract of leaves ?IC50 of 1 ?g. mL-1?; methanolic extracts of trunk bark (IC50 = 3 ?g. mL-1); methanolic extract of fruit pulp (IC50 = 3.75 ?g. mL-1); 9 ?g. mL-1 IC50 aqueous leaf extract; the aqueous extract of the stem (IC50 of 100 ?g. mL-1). Gallic acid, the standard antioxidant, showed an IC50 of 0.35 ?g. mL-1.