Ethanolic extraction and solvent-solvent partitioning of antioxidant compounds from green seaweed Enteromorpha intestinalis

Secondary metabolites of Enteromorpha intestinalis were extracted and their antioxidant effects evaluated. Crude extract was isolated using 96% ethanol at 60 °C for 2 h and then fractionated in order by solvents including hexane, chloroform, ethyl acetate, butanol and water. Extraction yield for crude extract was 3.17% and it varied between 4.07%-40.83% for fractions. Crude extract and fractions exhibited DPPH radical scavenging activity (22%-72%), ABTS radical scavenging (25%-62%), ferric reducing capacity (25%-82%) and total antioxidant activity (0.17-0.34 Abs) among which ethyl acetate fraction shoed the highest antioxidant activity throughout experiments. Besides, butanol (24 mg TA/ gr extract) and ethyl acetate (22 mg TA/ gr extract) fractions contained the highest amount of phenolic contents among crude extract and fractions. Overall, the results of current study revealed that ethyl acetate fraction of seaweed E. intestinalis possess the major bioactive compounds and may be utilized as an antioxidant in food industry.