POLYSACCHARIDES OF HIGHER FUNGI: SYSTEMATIZATION OF DATA ON EXTRACTION, STRUCTURE, BIO-LOGICAL PROPERTIES, AND PREBIOTIC POTENTIAL

The article is devoted to the study of isolation processes, determination of the chemical structure, and analysis of physicochemical and prebiotic properties of polysaccharides obtained from fruiting bodies and mycelial biomass of different representatives of higher fungi. Polysaccharides vary in structure, physicochemical properties, monosaccharide composition, glycosidic bond types, molecular mass, and solubility in water or alkaline solutions. This review article outlines the distribution of polysaccharides within the cell wall of higher fungi, organized into three distinct layers: the outer layer comprises glycoproteins; the middle layer consists of β-glucans; and the inner layer consists of a complex of chitin and β-glucan. The composition and physiological activity of polysaccharides depend on the species of fungus, cultivation conditions (type of substrate and environmental factors), stage of development, storage conditions, extraction method, and other variables. Different methods of extraction followed by purification and structural identification are discussed. The most abundant polysaccharides in edible and medicinal mushroom species are α-, β-, or mixed glucans. The review details the chemical structure and biological properties of major polysaccharides (β-glucans) isolated from diverse mushroom species: lentinan, schizophyllan, grifolan, ganoderan, and crestin. Information is presented on the correlations between the biological activity of polysaccharides and their chemical structure, monosaccharide composition, molecular weight, chemical modifications, branching patterns and conformation. The prebiotic potential of polysaccharides of higher fungi is described, with evidence showing that polysaccharide fractions of higher mushrooms promote growth of probiotic bacterial strains, modulate human intestinal microbiota, and enhance short-chain fatty acid production.