A new polysaccharide from fruit bodies of Morchella elata: Chemical structure and immunomodulation abilities.

A new polysaccharide (MEPS, Morchella elata polysaccharide) obtained through alkali extraction from fruit bodies of Morchella elata was purified by dialysis and sepharose-6B column chromatography. Chemical and spectroscopic analysis including GLC, GLC-MS, FT-IR, 1D NMR (1H, 13C, DEPT-135) and 2D NMR (TOCSY, HMQC, NOESY, DQF, ROESY, and HMBC) revealed that the backbone of its repeating unit was →6)-β-d-Manp-(1 → 3)-α-d-Glcp-(1 → 4)-α-d-Glcp-(1→, branched at C-3 of (1 → 4)-linked- α-d-Glcp by α-d-Manp-(1 → 4)-α-d-Glcp-(1 → 4)-α-d-Galp-(1 → . It was also found that a terminal β-l-fucopyranosyl residue was attached at C-3 of α-d-glucopyranosyl residue of the branched chain. In vitro evaluation of immune modulation of the polysaccharide revealed the significant macrophage polarizing properties and capability to induce an alternative phenotype M2 in peritoneal macrophages obtained from BALB/c mice. It was further confirmed by the ability to induce the expression of M2 polarizing cytokines, specifically IL-10.