Antioxidant properties of fucoidan extracted from brown alga Sargassum (Sargassum tenerrimum) and its ability to inhibit vannamei shrimp polyphenol oxidase enzyme

Fucoidan is one of the most important polysaccharides produced by brown seaweeds. In the present study, fucoidan was extracted from brown seaweed Sargassum tenerrimum and its properties include the extraction yield, carbohydrates, protein, sulfate, uronic acid content, antioxidant properties (DPPH free-radical scavenging and ferric reducing power) and its ability to inhibit polyphenol oxidase enzyme from vannamei shrimp (Litopenaeus vannamei) were assayed at concentrations of 0.5, 1 and 2mg/mL. The amount of the extraction yield, carbohydrate, protein, sulfates and uronic acid of the extracted fucoidan were 7.23, 36.51, 5.64, 11.57 and 9.22%, respectively. The rate of DPPH scavenging in fucoidan varied from 35.94 to 63.94% depending on the concentration (P<0.05). The rate of iron reduction varied from 0.23 in fucoidan at a concentration of 0.5mg/mL to 0.74 in treatment of 2mg/mL fucoidan. The highest inhibition of vannamei shrimp polyphenol oxidase enzyme was obtained in fucoidan with a concentration of 2mg/mL and equal to 64.72%. The results of this study showed that brown seaweed Sargassum tenerrimum is a rich source of fucoidan with significant antioxidant properties and polysaccharides extracted from this alga can be a natural and healthy inhibitor of polyphenol oxidase.