Extraction, Structural Characterization and Biological Activities of Polysaccharides Derived From <i>Hericium erinaceus</i>

<i>Hericium erinaceus</i> is acknowledged for its dual roles in medicinal and culinary contexts. The polysaccharides derived from <i>H. erinaceus</i> have attracted the attention of scientists owing to their bioactivities. This review focuses on the methodologies utilized for extraction and purification of <i>H. erinaceus</i> polysaccharides (HEP), as well as their structure and biological functions. We overview extraction and purification techniques, with hot water extraction and column chromatography being the most common. Subsequently, a thorough analysis of the structural characteristics of HEP was performed. The molecular weights of HEP ranged from 2.1 to 75,000 kDa. The monosaccharide composition of HEP was predominantly glucose. Additionally, the glycosidic bonds within HEP were primarily of the β-glycosidic type, with β-glucans characterized by 1 → 3 and 1 → 6 linkages representing the most prevalent structure. Furthermore, we summarize the biological activities and potential mechanistic pathways linked to HEP, which include immunomodulatory effects, antioxidant properties, hypoglycemic and hypolipidemic activities, as well as benefits in alleviating colitis and providing gastroprotective effects. Finally, we address the current challenges and limitations in the research surrounding <i>H. erinaceus</i> polysaccharides, while proposing promising directions for future investigations to further advance this area of study.