Phytochemical screening, free radical scavenging, antioxidant activity and phenolic content of Dodonaea viscose Jacq.

The purpose of this study was to evaluate the antioxidant potential of Dodonaea viscosa Jacq. A methanolic extract of the plant was dissolved in distilled water and sequentially partitioned with n-hexane, chloroform, ethyl acetate and n-butanol. Phytochemical screening showed the presence of phenolics, flavonoids and cardiac glycosides in large amounts in the chloroform, ethyl acetate and n-butanol fraction. The antioxidant potential of all these fractions and remaining aqueous fraction was evaluated by four methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, total antioxidant activity, the Ferric reducing antioxidant power (FRAP) assay and ferric thiocyanate assay along with the determination of their total phenolics. The results revealed that the ethyl acetate soluble fraction exhibited the highest percent inhibition of the DPPH radical as compared to the other fractions. It showed 81.14 +/- 1.38 % inhibition of the DPPH radical at a concentration of 60 mu g ml(-1). The concentration of this fraction leading to 50 % inhibition of the DPPH radical (IC50) was found to be 33.95 +/- 0.58 mu g ml(-1), relative to butylated hydroxytoluene (BHT), having an IC50 of 12.54 +/- 0.89 mu g mL(-1). It also showed the highest FRAP value (380.53 +/- 0.74 mu M of trolox equivalents) as well as the highest total phenolic contents (208.58 +/- 1.83 gallic acid equivalent (GAE) mu g g(-1)) and highest value of inhibition of lipid peroxidation (58.11 +/- 1.49 % at a concentration of 500 mu g ml(-1)) as compared to the other studied fractions. The chloroform fraction showed the highest total antioxidant activity, i.e., 1.078 +/- 0.59 (eq. to BHT).