Antioxidant activities of elaeis guineensis leaves

Fresh leaves from elaeis guineensis fronds were subjected to ultrasonic-assisted methanol extraction. the crude methanolic extract (meoh) was then fractionated by repeated extractions,sequentially with solvents of different polarity into n-hexane (hex),ethyl acetate (ea),water (water) and insoluble residue (insol) fractions. the antioxidant activity of the crude extract and its fractions was evaluated by in vitro 2,2-diphenyl-1-picrylhydrazyl (dpph) radical-scavenging activity,lipid peroxidation (lpo) inhibition and beta-carotene bleaching assays. total phenolic contents (tpc) in the fractions were determined with folin-ciocalteu reagent. the results indicated that the insol fraction showed the highest activity in dpph radical-scavenging activity assay and beta-carotene bleaching assay,while ea fraction exhibited highest activity through lpo inhibition. dpph radical-scavenging activity of the fractions was negatively correlated (correlation coefficients = -0.896,-0.943 respectively,p < 0.050) with the tpc based on pearson product moment correlation and spearman rank order correlation. the findings of present study suggests that oil palm leaves have high potential to be utilised as natural source of antioxidants in palm oil producing countries such as indonesia,malaysia and thailand,where oil palm leaves are abundantly available.