Inonotus obliquus Polysaccharides: Preparation, Structural Characteristics, Structure–Activity Relationships, Biological Activities and Applications

Inonotus obliquus, a rare medicinal and edible fungus, is rich in bioactive polysaccharides. These polysaccharides exhibit diverse biological activities, including gut microbiota-modulating, hypoglycemic, immunomodulatory, antitumor, antioxidant, hypolipidemic, and antiviral activities. Owing to these remarkable bioactivities and favorable safety profiles, Inonotus obliquus polysaccharides (IOPs) have garnered considerable research interest as promising candidates for the development of functional foods and therapeutic agents, particularly for the management of metabolic diseases and cancers. Based on the latest advances in the research on IOPs, this review summarizes its isolation and purification methods, structural characteristics, structure–activity relationships, biological properties and mechanisms, as well as their potential applications. It aims to provide valuable theoretical references for the further development and practical application of IOPs in the fields of medicine and functional foods.