Abstract:Grifola frondosa is a precious edible and medicinal fungus with anti-tumor, immunomodulatory, hypoglycemic, and antiviral activities. Polysaccharides are the main active component of G. frondosa, with the biological activity associated with the structure. We reviewed the structural characterization of active polysaccharides from G. frondosa. Some studies suggest that the blood sugar-lowering activity might be related to the chemical structure with β-1,6-glucan as the main chain, and the polysaccharides have better antitumor activity when the main chain is β-1,6-glucan or β-1,3-glucan. However, the complex structure makes it difficult to dissect the fine structure of G. frondosa polysaccharides. As a result, the structural characterization of G. frondosa polysaccharides is generally limited to monosaccharide composition, molecular weight, glycosidic bond type, branching structure, and rough molecular chain conformation. The advancing 2D-NMR and high-resolution mass spectrometry will help to disclose the structure-activity relationship and provide a theoretical basis for the development and utilization of G. frondosa polysaccharides.