Structural analysis, in vitro antioxidant and lipid-lowering activities of purified Tremella fuciformis polysaccharide fractions

To investigate the composition, structure, and physical and chemical properties of Tremella fuciformis polysaccharide (TFPS), four new polysaccharide fractions (TFPS1, TFPS2, TFPS3, and TFPS4) were successfully isolated from hot water-extracted crude polysaccharides using a DEAE-52 cellulose column. Their structures were analyzed using FT-IR, SEM, HPGPC, monosaccharide composition, Congo red and I2-KI experiments. TFPS1 was found to be a heteropolysaccharide with a molecular weight of 742 Da for the major polysaccharide fragment. TFPS2, TFPS3, and TFPS4 were identified as single-component homogeneous polysaccharides with molecular weights of 350774 Da, 622675 Da, and 624724 Da, respectively. Glucose was the dominant monosaccharide of TFPS1 and TFPS2, while mannose was the major monosaccharide of TFPS3 and TFPS4. The results showed that TFPS1 and TFPS2 displayed a stable triple helix structure in aqueous solution, while TFPS3 and TFPS4 had longer side chains and more branched chains. Additionally, all four TFPSs showed in vitro antioxidant activity, as well as significant cholesterol binding and sodium taurocholate binding abilities.