Structural Characterization and Antioxidant Activity of Five Kinds of Edible Fungus Polysaccharides

Five kinds of edible fungus polysaccharides were studied, including TFP (Tremella fuciformis polysaccharides), AAP (Auricularia auricula-judae polysaccharidses), PEP (Pleurotus eryngii polysaccharides), FVP (Flammulina velutipes polysaccharides) and HEP (Hericium erinaceus polysaccharides). The monosaccharide composition of polysaccharide was studied by columnar derivatization and high performance liquid chromatography (HPLC). Their structural characteristics were analyzed using Fourier transform infrared spectroscopy, Congo red test and X-ray diffraction. Then, their antioxidant activities were analyzed. Pearson correlation analysis test were used to analyze the relationship between the antioxidant activity and composition of polysaccharides, The results showed that TFP and AAP were mainly composed of mannose (38.4%, 44.4%) and glucose (28.2%, 24.4%), PEP, FVP and HEP were mainly composed of glucose (51.5%~59.9%) and galactose (18.9%~28.4%). Five kinds of edible fungus polysaccharides all contain polysaccharides feature peaks, HEP had three-helix structure and its degree of crystallinity was significantly higher than that of the other four kinds of polysaccharides. All the five edible fungal polysaccharides had antioxidant activity, the contents of uronic acid and glucuronic acids were negatively correlated with the IC₅₀ values of ABTS⁺·and DPPH·, the contents of sulfuric acid were positively correlated with the IC₅₀ values of DPPH·;the content of protein and glucose was negatively correlated with the IC₅₀ value of·OH, the content of mannose was positively correlated;the contents of fucose were positively correlated with the IC₅₀ values of the superoxide anion scavenging activity. Results indicated that the high antioxidant activity of fungal polysaccharides was related to their chemical structure and composition. At the same time, results elucidated the structural characteristics of polysaccharides with high antioxidant activity.