Evaluation of comparative antioxidant potential of aqueous and organic fractions of Ipomoea carnea

Abstract

The methanolic extract of Ipomoea carnea Jacq. was dissolved in distilled water and partitioned with n-hexane, chloroform, ethyl acetate and n-butanol successively. The antioxidant potential of all these fractions and remaining aqueous fraction was evaluated by four methods: DPPH free radical scavenging activity, total antioxidant activity, FRAP assay and ferric thiocyanate assay and total phonolics were also determined. All the fractions showed significant antioxidant potential. The results revealed that n-butanol fraction showed highest value of % inhibition of DPPH radical (91.11% ± 0.68), IC50 of n-butanol fraction was 74.65 ± 1.4 µg/ml,  relative to butylated hydroxytoluene (BHT), having IC50 of 12.1 ± 0.92 mg/mL. The chloroform soluble fraction showed highest total antioxidant activity (0.9096 ± 0.1) and highest total phenolic contents (113.05 ± 1.2 mg of gallic acid equivalents) as compared to other fractions. The ethyl acetate soluble fraction exhibited highest FRAP value (511.99 ± 1.8 µg of trolox equivalents) as well as highest value of inhibition of lipid peroxidation (61.87% ± 1.2) as compared to other fractions.   Key words: Ipomoea carnea Jacq., DPPH assay, total antioxidant activity, FRAP value, total phenolics, Inhibition of lipid peroxidation (%).