Phytochemical Assessment and Antioxidant Activities of Alcoholic and Aqueous Extracts of Acacia mearnsii De Wild

Phenolic compounds are well known for their antioxidant activities. The objectives of this study were to determine the phenolic content of the crude extracts of Acacia mearnsii De Wild and to evaluate the antioxidant properties of these extracts. The Folin-ciocalteu procedure was used to assess the total phenolic compositions of the extracts as garlic acid equivalents. Antioxidant activity was evaluated using 2,2-Azinobis-3-ethyl benzothiazoline-6-sulfonic acid (ABTS) diammonium salt and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging methods. All the extracts showed antioxidant potential. Ethanolic extract had the highest total flavonoids. Acetone extract had the highest total phenolic contents. The total proanthocyanidins was highest in the methanol extract while aqueous extracts had the least of these phytochemicals. The reducing power of the extracts of A. mearnsii was dose dependent. Aqueous extract showed the least reducing power, methanol extract indicated the highest reducing power. The reducing power of the extracts is lower than those obtained from the reference standard such as Butylated Hydroxytoluene (BHT), Rutin and ascorbic acid. 2,2-Azinobis-3-ethyl Benzothiazoline-6-Sulfonic acid (ABTS) diammonium salt showed that ethanol extract exhibited the highest activity at the highest concentration tested. 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay indicated that ethanol extract had the highest activity at the lowest concentration and the activities of all the extracts decreased with increase in their concentrations. This study revealed a positive linear correlation between the total phenolic content and antioxidant activity of the extracts of A. mearnsii.