Immunomodulatory and antivirus activities of bioactive polysaccharides and structure-function relationship

Bioactive polysaccharides with immunomodulatory and antivirus effects have been widely investigated. However, due to the complexity of molecular structure and insufficient characterization, the correlation between structure and immunomodulatory/antivirus bioactivities have not been well summarized. This review highlights three most studied polysaccharides (i.e. mannan, pectin and glucan) with promising immunomodulatory activities, and the antivirus effects of sulfated polysaccharides and possible mechanisms are also discussed. The proposed structure-function relationship will help extend the application of bioactive polysaccharides as key ingredients in plant-based food, cosmetics, or therapeutic products.