Preparation, physicochemical properties, and immunomodulatory activity of glycoproteins from Syngnathoides biaculeatus

Syngnathoides biaculeatus , a potential functional food from marine sources, was found to enhance nonspecific immunity, but its functional ingredients have rarely been reported. Therefore, this study focused on the preparation and physicochemical properties of its water-soluble natural ingredients with their immunomodulatory activities and potential mechanisms. Firstly, we optimized the extraction method of glycoproteins from S. biaculeatus and prepared the crude glycoprotein SYB, from which the fraction glycoprotein SYB-1 was further purified. The carbohydrates of SYB-1 were 8.46% comprising mannose, glucose, and galactose, with an average molecular weight of 9.423 kDa. Amino acid analysis demonstrated that its major amino acids are glycine, glutamic acid, aspartic acid, and proline, with a total amino acid content of 88.81%. Furthermore, SYB-1 could significantly increase the cell viability of macrophages, and promote the release of NO, TNF- α , and IL-6. Metabolomics revealed that it was associated with arachidonic acid metabolism. The CYP450 enzyme family members and PTGS2 may be key targets for the regulatory role. These results suggested that the glycoprotein of S. biaculeatus may be an attractive functional food supplement from natural sources for immunocompromised populations. Graphical