Purification, structural characterization and immunomodulatory activities of a polysaccharide from the fruiting body of Morchella sextelata

A novel polysaccharide (MSP-1) was isolated from the fruiting body of Morchella sextelata and purified using DEAE-52 and Sephadex G-75. The molecular weight of MSP-1 was 1.17 × 104 Da, as detected by HPLC analysis. The monosaccharide composition of MSP-1 was mannose and glucose at a ratio of 1.00: 1.25. Methylation and NMR results revealed that the backbone of MSP-1 was composed of →4)-β-D-Manp-(1→, →4)-β-D-Glcp-(1→, →4)-α-D-Glcp-(1→, and →4, 6)-α-D-Glcp-(1→. SEM images of MSP-1 presented a dense network structure with porous characterizations. The immunomodulatory activities of MSP-1 were evaluated using RAW264.7 cells, and the results showed that MSP-1 promoted proliferative and phagocytic activity and increased the production of NO, TNF-α and IL-6. These results indicated that MSP-1 exhibited significant immunomodulatory activities. •A novel heteropolysaccharide (MSP-1) was purified from the fruiting body of Morchella sextelata.•The complete structure of M. sextelata polysaccharide was exhibited for the first time in the present study.•The 3D structure of MSP-1 presented a dense network structure with porous characterizations.•MSP-1 exhibited strong immunomodulatory activities by promoting proliferative and phagocytic activity and obviously increasing the production of NO, TNF-α and IL-6 on RAW264.7 cells.