Immunostimulant, anti-inflammatory, and antinociceptive effects of a mushroom-derived (1→3), (1→6)-β-D-glucan: In vivo and in vitro models.

Natural molecules with biological properties are widely investigated to better understand their broad range of functions. Among these, (1→3),(1→6)-β-D-glucans are extensively studied due to their remarkable biological activities, particularly their immunomodulatory effects. In this study, we extracted and purified a (1→3),(1→6)-β-D-glucan (Mw 6.02 × 105 g.mol-1) from the mushroom Amanita semigemmata. The polysaccharide (AS-P) was chemically characterized by 1H, 13C and HSQC-NMR, methylation, monosaccharide composition, homogeneity and molecular weight analysis. Additionally, sugar and protein content were quantified. In vitro experiments demonstrated that AS-P is non-cytotoxic at concentrations up to 500 μg.mL-1 and modulates RAW 264.7 macrophage activity. AS-P significantly reduced nitric oxide (NO) production by 50.95 % and 60.14 % at concentrations of 250 and 500 μg.mL-1, respectively, when co-incubated with lipopolysaccharide (LPS). Furthermore, AS-P induced a downregulation in the pro-inflammatory cytokine IL-6 and an upregulation of TNF and MCP-1 cytokines, indicating a dual modulatory effect. In vivo assays further demonstrated that the AS-P fraction was highly effective in reducing pain by 97 % during the inflammatory phase (15 to 30 min) at a dose of 30 mg.kg-1 following intraplantar injection of formalin solution. These findings highlight the potential of AS-P as a natural immunomodulatory compound, exhibiting dual regulation of cytokine production while exerting both anti-inflammatory and antinociceptive effects.