Antioxidant properties and Vannamei shrimp (Litopenaeus vannamei) polyphenoloxidase inhibitory activity of different brown seaweeds extracts

At the present study, phlorotannin content, antioxidant properties (DPPH free-radical scavenging and ferric reducing power) and inhibitory of polyphenoloxidase enzyme from Vannamei shrimp (Litopenaeus vannamei) in different extracts (first and ethyl-acetate) extracted from brown seaweeds Nizimuddinia zanardinii, Sargassum ilicifolium, Sargassum cristaefolium and Stoechospermum marginatum with methanol 100% and 70% were investigated. Among different seaweeds species, the highest amount of phlorotannin (13.21 mg PHG/g), DPPH scavenging (72.64%) and reducing power (0.96) were measured in the ethyl-acetate extract of N. zanardinii in methanol 100% treatment. Phlorotannin compounds including Eckol, Dieckol, Bieckol were identified by using of TLC in the ethyl acetate extract of N. zanardinii. The results showed that phlorotannin content and antioxidant activity varies in different species depending on seaweed specie, type of extract and type of extraction solvent. The amount of Vannamei shrimp polyphenoloxidase inhibition was different between various extract and seaweeds; and the highest amount of inhibition (71.11%) was measured in the ethyl-acetate extract of N. zanardinii. The results of present study showed that seaweed extracts with high amount of phlorotannins content could be considered as natural and safe polyphenoloxidase enzyme inhibitor.