Protective Effects of Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Agaricomycetes) Polysaccharides Extracted via Free Radical-Assisted Method on DSS-Induced Ulcerative Colitis in Mice.

This study investigated the protective effects of Ganoderma lucidum polysaccharides against ulcerative colitis (UC), addressing the challenges posed by the rigid cell wall structure and low solubility of its polysaccharides, as well as the unclear anti-ulcerative colitis potential. G. lucidum polysaccharides were extracted using a free radical-assisted extraction method, followed by ethanol precipitation and deproteinization. Monosaccharide composition and molecular weight were then analyzed. A dextran sulfate sodium (DSS)-induced UC mouse model was established to evaluate the protective effects of G. lucidum polysaccharides. Monosaccharide composition analysis revealed that G. lucidum polysaccharides primarily consisted of D-mannose, D-glucuronic acid, and D-glucose, with molar percentages of 2.49:2.36:88.16, respectively. The weight-average and number-average molecular weights were 50.017 and 22.851 kDa, respectively. Compared with the negative control group, G. lucidum polysaccharides mitigated DSS-induced weight loss and reduced the disease activity index (DAI) score in mice. G. lucidum polysaccharides significantly enhanced the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum (P < 0.05). Furthermore, G. lucidum polysaccharides significantly reduced the levels of inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in colonic tissues (P < 0.05) and alleviated the DSS-induced increase in colonic permeability. 16S rRNA sequencing of gut microbiota revealed that G. lucidum polysaccharides reduced the Firmicutes/Bacteroidetes (F/B) ratio elevated by DSS at the phylum level. At the genus level, G. lucidum polysaccharides intervention increased the abundance of beneficial bacteria such as Muribaculum. In conclusion, G. lucidum polysaccharides extracted using the free radical-assisted extraction method exhibit a protective effect against UC and holds significant potential for development.