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.
Keywords: Xylaria nigripes; anti-inflammatory activity; physicochemical properties; synergistic effect; water soluble polysaccharides.
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