Characterization and immunomodulatory effect of an alkali-extracted galactomannan from Morchella esculenta

In our continuous exploration for bioactive polysaccharides, a novel polysaccharide FMP-2 was isolated and purified from the fruiting bodies of Morchella esculenta by alkali-assisted extraction. FMP-2 had an average molecular weight of 1.09 x 10(6) Da and contained mannose, glucuronic acid, glucose, galactose, and arabinose in a molar ratio of 4.10:0.22:1.00:5.75:0.44. The backbone of FMP-2 mainly consisted of 1,2-alpha-D-Galp, 1,6-alpha-D-Galp, and 1,4-alpha-D-Manp, with branches of 1,4,6-alpha-D-Manp and 1,2,6-alpha-D-Galp. FMP-2 can stimulate phagocytosis and promote the secretion of NO, ROS, and cytokines like IL-6, IL-1 beta, and TNF-alpha in RAW264.7 cells ranging from 25 to 400 mu g/mL. FMP-2 had great repairing effect on the immune injury of zebrafish induced by chloram-phenicol. The phagocytosis ability of zebrafish macrophages and the proliferation of neutrophils can be greatly enhanced by polysaccharide FMP-2 with concentrations from 50 to 200 mu g/mL. These findings suggest that FMP-2 might be used as a potential immunomodulator in the food and pharmaceutical industries.

Automated summary

A novel polysaccharide, FMP-2, was isolated and purified from the fruiting bodies of Morchella esculenta using alkali-assisted extraction. FMP-2 exhibited immunomodulatory effects, stimulating phagocytosis and the secretion of cytokines. It also showed a repairing effect on immune injury. These findings suggest that FMP-2 has potential applications as an immunomodulator in the food and pharmaceutical industries.