Antioxidant Properties of Ethanol Crude Extract, Partitioned and Chromatographic Fractions of Acacia ataxacantha DC (Fabaceae) stem bark

Acacia ataxacantha is used in the management of several diseases in many parts of Nigeria. The study was carried out to evaluate the antioxidant potential of ethanol crude extract, partitioned and chromatographic fractions of the stem bark of Acacia ataxacantha. The dried powdered stem bark was extracted with 70% ethanol and the extract was partitioned with ethyl acetate (EA) and 1-butanol (BT) in succession. The EA fraction was subjected to flash column chromatography while the BT fraction was further fractionated by gel filtration using sephadex LH20. The eluates from the EA fraction eluted with dichloromethane /ethyl acetate (95:5) produced a single spot in iodine tank and were pooled together to give a white solid (EAF). The eluates from the BT fraction which produced one spot in iodine tank were pulled together and coded BTF. The crude extract, EA, BT, EAF and BTF were screened for antioxidant properties using 2, 2- diphenyl-1-picrylhydrazyl (DPPH), 2, 2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) assay procedures with ascorbic acid (AA) used as the standard. The crude extract produced the greatest inhibition in the ABTS assay with IC50 of 0.46±0.03 while the EAF produced the least activity in the FRAP assay with IC50 of 37.45±0.06. The crude extract and BF produced the best antioxidant properties in all the assay methods employed hence, the plant has the potential to be developed into an antioxidant compounds.