Ultrasound assisted extraction of antioxidant compounds from four Persian Gulf seaweed

The antioxidant extract of four seaweeds Sargassum angustifolium, Padina astraulis, Cystoseria merica, Colopomenia sinuosa was prepared by ultrasonic methods with three solvents (water, water/ethanol and ethanol) under 25 kHz, 400W conditions. In this study, aquatic extract of S. angustifolium had the highest phenolic content (P<0.05). The amount of phenolic compounds in water/ethanol extracts of S. angustifolium were significantly higher than other seaweed extracts. (P<0.05). The aqueous extract of C. merica had the highest amount of DPPH radical scavenging relative to the aqueous extracts of other seaweeds (P<0.05). The aqueous/ethanolic extracts of S. angustifolium had significantly higher radical scavenging than other algae/ethanol extracts (P<0.05). Also, the anti-radical properties of Ethanol extract of C. merica was higher than ethanloic extract of other algae (P<0.05). The water extracts in all species had more phenolic contents, but in DPPH test, water/ethanol extracts of S. angustifolium had highest radical scavenging activity. The result show that S. angustifolium and C. merica were suitable for antioxidants extraction.