Anti-inflammatory and intestinal microbiota modulation properties of Ganoderma lucidum β-d-glucans with different...

This study systematically investigated the therapeutic effects and the corresponding mechanisms of β-D-glucans from Ganoderma lucidum (G. lucidum) with different molecular weights (M_ws) on ulcerative colitis (UC). Results showed that three β-d-glucans (GLPS, GLPN and GLPW) from G. lucidum with different M_ws exhibited the significant activities on the reduction of typical symptoms of UC by regulating inflammatory cytokine levels, modulating intestinal immunity, improving intestinal microbiota and metabolism of short-chain fatty acids (SCFAs) in the dextran sulfate sodium (DSS)-induced mice model. Among them, the effects of the microwave assisted degraded fraction (GLPW) mainly containing two fractions with smaller M_w (1.33 × 10⁴ and 3.51 × 10³ g/mol) on the regulation of inflammatory factors and SCFAs metabolism were found to be comparable to those of GLPN with medium M_w (3.49 × 10⁴ g/mol), and superior to those of GLPS with large M_w (2.42 × 10⁶ g/mol). The effect of GLPW on regulation of intestinal microbiota was even better than that of GLPN. These findings suggested that lowering M_w by means of physical degradation could improve the anti-inflammatory activities of G. lucidum β-d-glucans. The analysis of anti-inflammatory mechanism also provided a feasible and theoretical basis for potential use of degraded β-d-glucans in the prevention and treatment of UC.