ANTIOXIDANT ACTIVITY OF THE LEAVES AND BARKS OF SELECTED PLANTS USED AS ANTIMALARIAL REMEDY

Nigeria has been known for its rich biological diversity. The removal of barks is a vital point of concern in conservational studies because of its importance to the survival of the plants. In previous studies, the combination of leaves and barks used for research have proved to have antimalarial properties. This study was conducted to ascertain the antioxidant activity of the leaves and barks of the selected plants and to determine whether leaves and barks can be used independently. Five medicinal plants were used, which include Kigelia africana, Alstonia boonei, Mangifera indica, Telfairia occidentalis and Anacardium occidentale. Successive extraction was done using hexane, chloroform, ethyl acetate, and methanol. Qualitative screening showed the presence of tannins, flavonoids, saponins, and terpenoids in varying proportions with the polar solvents having more presence than the non-polar solvents. The total flavonoids, tannins, terpenoids, and saponins contents for all the leaves samples, determined through quantitative screening, ranged from 10.33 ± 0.02 to 20.53 + 0.05 mg/ml, 0.03 + 0.01 to 0.16 ± 0.01 mg/ml, 0.05 + 0.01 to 0.33 ± 0.03 mg/ml and 0.03 ± 0.01 to 0.16 ± 0.01 mg/ml respectively. Meanwhile, the total flavonoids, tannins, terpenoids, and saponins contents for all the bark samples ranged from 6.87 ± 0.03 to 15.89 ± 0.05 mg/ml, 0.06 ± 0.01 to 0.11 ± 0.02 mg/ml, 0.02 ± 0.01 to 0.21 ± 0.02 mg/ml and 0.01 to 0.11 ± 0.01 mg/ml respectively. Comparison between both extracts showed that the leaves extracts exhibited better antioxidant activity compared to the bark extracts. This implies that leaves can function independently of barks for antimalarial remedy which then allows the usage of more leaves and less or no barks leading to the conservation of medicinal plants.