Structural characterization of a polysaccharide from Trametes sanguinea Lloyd with immune-enhancing activity via activation of TLR4.

A bioactive polysaccharide (TS2–2A) with a molecular weight of 15 kDa was isolated from Trametes sanguinea Lloyd, a medicinal food homologous fungus, by water extraction-alcohol precipitation and chromatographic separation. NMR analysis of polysaccharide and MS/MS analysis of its oligosaccharide indicated that TS2–2A featured a novel straight chain with a backbone of 1,3-α- d -glucopyranose and 1,4-β- d -glucopyranose at a molar ratio of 1:4. Moreover, TS2–2A, recognized by Toll-like receptor 4 (TLR4), stimulated RAW 264.7 macrophages to release related cytokines and contributed to immune-enhancing effects. Briefly, with remarkable immune-enhancing activity and noncytotoxicity, TS2–2A was proposed to be a potential immune enhancer for supplementing drugs or functional foods. [Display omitted] • Polysaccharide (TS2–2A) was isolated from Trametes sanguinea Lloyd. • TS2–2A mainly comprised glucose with a molecular weight of 15 kDa. • The main structure of TS2–2A was a straight chain with a backbone of →3)-α-D-Glc p -(1 → and →4)-β-D-Glc p -(1 → at a molar ratio of 1:4. • TS2–2A exerted immune-enhancing effects via activation of TLR4. [ABSTRACT FROM AUTHOR]