Determination of Antioxidant Activity and Phytoconstituent Screening of Euphorbia heterophylla Linn.

ABSTRACT

Aim: To carry out qualitative determination of phytochemicals and evaluate antioxidant potential of Euphorbia heterophylla Linn. Place and Duration of Study Department of Chemistry, Government College University Lahore, Pakistan, between October, 2011 and February, 2012. Material and Method: The methanolic extract of the plant was dissolved in distilled water and partitioned with n-hexane, chloroform, ethyl acetate and n-butanol sequentially. The antioxidant potential of all these fractions and remaining aqueous fraction was analyzed by these methods: 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging activity, total antioxidant activity, Ferric Reducing Antioxidant Power (FRAP) assay, Ferric Thiocyanate (FTC) assay while Folin-Ciocalteu colorimetric method was used to analyse total phenolic content. Phytochemical analysis were performed on the plant extracts to detect the presence of secondary metabolites. Results: Phytochemical screening revealed phenolics and flavonoids in abundance inchloroform soluble fraction, ethyl acetate soluble fraction and n-butanol soluble fraction. Also the ethyl acetate soluble fraction, n-butanol soluble fraction and remaining aqueous fraction contained saponins and sugars. Terpenoids were detected in all other fractions except the aqueous fraction. Alkaloids were determined in ethyl acetate and n-butanol soluble fraction only while tannins and cardiac glycosides were present in n-butanol soluble fraction and ethyl acetate soluble fraction respectively. Antioxidant assays revealed that Ethyl acetate soluble fraction exhibited highest percent inhibition of DPPH radical i.e. 80.09±0.87% at a concentration of 120 μg/ml as compared to other fractions. IC50 value of ethyl acetate fraction was found to be 36.85±1.8 μg/ml relative to ascorbic acid having IC50 value 58.8±0.89 μg/ml. It also showed the highest value of total antioxidant activity i.e. 0.918±0.08 as well as highest FRAP value 200.05±0.4 TE μM/ml, highest amount of total phenolic compounds (190.1±1.21 GAE mg/g) and highest percentage of inhibition of lipid peroxidation (54.23±0.57%). Chloroform soluble fraction showed IC50 value of 149.84±1.02, total antioxidant activity 0.739±0.06; FRAP value115.15±0.2 μM/ml, total phenolic content 137.1±1.4 GAE mg/g and 41.31±0.53% percent inhibition of lipid peroxidation. n-Butanol soluble fraction showed IC50 value of 117.67±0.7, total antioxidant activity 0.532±0.03, FRAP value127.5±0.9 μM/ml, total phenolic content 93.5±0.3 GAE mg/g and 32.15±0.9% percent inhibition of lipid peroxidation. n-Hexane soluble fraction showed IC50 value of 769.7±1.5, antioxidant activity 0.174±0.07, FRAP value 98.26±0.8 μM/ml, total phenolic content 19.5±1.23 GAE mg/g and 12.09±0.8% percent inhibition of lipid peroxidation. Aqueous fraction showed IC50 value of 669.3±1.04, antioxidant activity 0.152±0.041; FRAP value 68.7±0.3 μM/ml, total phenolic content 36.3±0.9 GAE mg/g and 25.01±0.96% percent inhibition of lipid peroxidation. Conclusion: Ethyl acetate soluble fraction was found to be rich in natural antioxidants and a good source of phytochemicals.