The Main Structural Unit Elucidation and Immunomodulatory Activity In Vitro of a Selenium-Enriched Polysaccharide Produced by Pleurotus ostreatus

In recent years, the structure of selenium-enriched polysaccharides and their application in immunomodulation have attracted much attention. In previous studies, we extracted and purified a novel selenium-enriched Pleurotus ostreatus polysaccharide called Se-POP-21, but its structure and immunomodulatory activity were still unclear. In this study, the main structural unit formula of Se-POP-21 was characterized by methylation analysis and an NMR experiment. The results showed that the backbone of Se-POP-21 was ->[2,6)-alpha-D-Galp-(1 -> 6)-alpha-D-Galp-(1](4)-> 2,4)-beta-L-Arap-(1 ->[2,6)-alpha-D-Galp-(1 -> 6)-alpha-D-Galp-(1](4)->, branched chain of beta-D-Manp-(1 -> and beta-D-Manp-(1 -> 4)-beta-L-Arap-(1 -> connected with -> 2,6)-alpha-D-Galp-(1 -> and -> 2,4)-beta-L-Arap-(1 ->,respectively, through the O-2 bond. In vitro cell experiments indicated that Se-POP-21 could significantly enhance the proliferation and phagocytosis of RAW264.7 cells, upregulate the expression of costimulatory molecules CD80/CD86, and promote RAW264.7 cells to secrete NO, ROS, TNF-alpha, IL-1 beta, and IL-6 by activating the NF-kappa B protein. The results of this study indicate that Se-POP-21 can effectively activate RAW264.7 cells. Thus, it has the potential to be used in immunomodulatory drugs or functional foods.

Automated summary

The structure of a selenium-enriched polysaccharide, Se-POP-21, was characterized and its immunomodulatory activity was investigated. The polysaccharide was found to enhance cell proliferation and phagocytosis, increase expression of costimulatory molecules, and induce secretion of immune-related molecules. This study suggests the potential application of Se-POP-21 in immunomodulatory drugs or functional foods.