Antioxidant Properties and Total Phenolic Contents of Extracts from Three Macroalgae Collected from Chabahar Coasts

Water, ethanol and ethanol/water extracts from three species of seaweeds ( Padina australis , Stoechospermum marginatum and Ahnfeltiopsis pygmaea ) collected along Chabahar coasts were investigated for antioxidant activity with five in vitro antioxidant assays including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), Trolex equivalent antioxidant capacity (TEAC), ferric-reducing antioxidant power assay (FRAP), phosphomolybdenum (PMB) and the reducing power (RP). In addition, Folin–Ciocalteu was used to measure phenolic content (TPC) to determine the antioxidant components. In the three seaweeds species, ethanol extracts showed higher amounts of the phenolic compounds and antioxidant capacities (by DPPH, PMB, FRAP and TEAC) when compared to water and ethanol/water. The total phenolic content of analyzed seaweeds, ranged from 69.66 to 76 mg GAE/g extract in the water, from 96 to 126.66 mg GAE/g extract in ethanol and from 81.66 to 92.66 mg GAE/g extract in ethanol/water. The ethanol extract of brown alga S. marginatum contained significantly ( p < 0.05) higher levels of phenolic compounds and antioxidant activities in five different methods when compared to other extracts, and the next ranks, respectively, belonged to ethanol and ethanol/water extracts of brown and red algal species P. australis and A . pygmaea . This study clearly demonstrated that ethanol had higher efficiency to extract phenolic in comparison to the water and ethanol/water. Furthermore, the mentioned seaweeds may be potent rich resources of the natural antioxidants for food utilizations and thus were recommended for additional assessment of the antioxidant activities in the real food systems.