Differences in water soluble non-digestible polysaccharides and anti-inflammatory activities of fruiting bodies from two cultivated Xylaria nigripes strains

Polysaccharides including β-glucans are important bioactive components of mushroom. Xylaria nigripes is a popular medicinal fungus that has been used for treating trauma, insomnia and mental illness. This study examined the physicochemical characteristics and anti-inflammatory activities of water soluble non-digestible polysaccharides (TXNP and CXNP) from fruiting bodies of two cultivated X. nigripes strains (TXN and CXN). Results showed that both TXNP and CXNP possessed relatively similar FT-IR spectra. TXNP had a triple helix conformation and molecular weight of 853.8 kDa, whereas the molecular weight of CXNP was 14.7 kDa. The monosaccharide composition of TXNP was predominantly glucose, whereas CXNP contained xylose, mannose and glucose. Although both TXNP and CXNP dose-dependently suppressed the production of NO, IL-1β, TNF-α and PGE2, as well as the expression of iNOS, COX-2 and NF-κB in the lipopolysaccharide-induced RAW264.7 macrophages, the potency of TXNP was stronger. This study reveals that under similar conditions of cultivation and extraction procedures, the different physicochemical characteristics of polysaccharides from TXN and CXN may have contributed to the differences in their anti-inflammatory potency.