Structural Elucidation of a Polysaccharide from Flammulina velutipes and Its Lipid-Lowering and Immunomodulation Activities.

FVPT1, a novel heteropolysaccharide, was purified from the fruiting body of Flammulina velutipes using magnetic-field-assisted three-phase partitioning and gel permeation chromatography. The structure was characterized using monosaccharide composition and methylation analysis, infrared spectroscopy and nuclear magnetic resonance (NMR). The FVPT1 (~1.64 × 10 4 Da) was composed of L-fucose, D-galactose, D-glucose and D-mannose at a molar ratio of 1.0:3.5:1.0:1.4. The polysaccharide repeating unit of FVPT1 was established with methylation analyses and NMR spectroscopy. Moreover, a zebrafish larva hyperlipidemia model test demonstrated that FVPT1 can show appreciable lipid-lowering effects. In addition, the FVPT1 exhibited remarkable immunoregulatory activity by increasing nitric oxide, interleukin (IL)-1β and IL-1 secretion in macrophages. Therefore, these results suggest that FVPT1 has the potential to be developed into a new immune or hypolipidemic health product.