Synergistic anti-inflammatory effects of different polysaccharide components from Xylaria nigripes

Nondigestible polysaccharides are essential nutrients, which are also important bioactive constituents of mushrooms. This study aimed to investigate the physicochemical properties and anti-inflammatory effects of different polysaccharide components of Xylaria nigripes in lipopolysaccharides (LPS)-induced RAW264.7 macrophages. Results showed that X. nigripes nondigestible polysaccharide (XN) possessed a molecular weight of 910.7 kDa and mainly composed of glucose; it effectively suppressed NO, TNF-α, and IL-6 production. Based on molecular weight, two bioactive polysaccharide components (F1 and F2) were isolated from XN. F1 was a glucan with high molecular weight (885.2 kDa), whereas F2 was a low molecular weight heteropolysaccharide (24.5 kDa) composing of glucose, mannose, and galactose. F1 showed stronger inhibitory effects on NO, TNF-α, and IL-6 production than F2, however, its inhibitory effects were weaker than XN. Further analysis demonstrated that the combined treatment of F1 and F2 exhibited anti-inflammatory activity as good as XN, and they possessed synergistic effects on inhibiting pro-inflammatory mediator production. PRACTICAL APPLICATIONS: Polysaccharides are essential nutrients, and are major bioactive constituents of mushrooms. This study isolated two bioactive polysaccharide components from Xylaria nigripes, namely F1 and F2. F1 was a high molecular weight glucan, whereas F2 was a low molecular weight heteropolysaccharide. F1 showed stronger anti-inflammatory activity than F2, but was weaker than their combined treatment (F1 + F2). Different polysaccharide components were shown to possess synergistic anti-inflammatory effects, suggesting their importance in the formulation of polysaccharide-based products.