Polysaccharides from fungi: A review on their extraction, purification, structural features, and biological activities

•A variety of extraction methods of polysaccharides from fungi are reviewed and compared.•Purification methods, structure of fungal polysaccharides were reviewed.•Diverse biological activities of fungal polysaccharides were outlined.•Structure-activity relationships of fungal polysaccharides were discussed. Fungi, as the unique natural resource, are rich in polysaccharides, proteins, fats, vitamins, and other components. Therefore, they have good medical and nutritional values. Polysaccharides are considered one of the most important bioactive components in fungi. Increasing researches have confirmed that fungal polysaccharides have various biological activities, such as antioxidant, immunomodulatory, anti-tumor, hepatoprotective, anti-aging, anti-inflammatory, and radioprotective activities. Consequently, the research progresses and future prospects of fungal polysaccharides must be systematically reviewed to promote their better understanding. This paper reviewed the extraction, purification, structure, biological activity, and underlying molecular mechanisms of fungal polysaccharides. Moreover, the structure–activity relationships of fungal polysaccharides were emphasized and discussed. This review can provide scientific basis for the research and industrial utilization of fungal polysaccharides.