Effects of different solvents on the phenolic compounds and antioxidant properties of brown seaweeds, Nizimuddinia zanardinii (Schiffner) P.C.Silva and Padina australis Hauck

Seaweeds are one of the most important resources for extraction of natural bioactive components. In the present study, effect of different solvents (methanol 100%, methanol 70%, acetone 100%, and acetone 70%) was evaluated on the phenolic components extraction and antioxidant properties of two brown seaweed species (N. zanardinii and P. australis) from Chabahar coasts. Antioxidant activities of the first extract and its fractions including chloroform, dichloromethane, ethyl acetate and aqueous phase were measured using total phenolic content, DPPH free radical scavenging activity, reduction power and metal chelating activity methods. Phenol content and antioxidant properties were higher in 100% methanolic extract compared to other treatments for both algae. Ethyl acetate fraction of N. zanardinii showed the best antioxidant activities. Antioxidant properties of N. zanardinii were considerably higher than P. australis. The results showed that N. zanardinii can be considered as potential sources of natural antioxidants.