Chemical Modifications and Biological Activities of Polysaccharides.

The chemical modifications of polysaccharides involve the use of chemical methods to modify some special structures or functional groups of polysaccharides on the main chains or side chains. The chemical methods include sulfation, phosphorylation, acetylation, carboxymethylation etc. Therefore, spatial structures, and physical and chemical properties of polysaccharides change, which enhance the biological activities of polysaccharides, e.g., immune regulation, antivirus, anti-tumor, anti-oxidation, etc.