Characterization of a neutral polysaccharide from pumpkin (Cucurbita moschata Duch) with potential immunomodulatory activity

Int J Biol Macromol. 2021 Oct 1;188:729-739. doi: 10.1016/j.ijbiomac.2021.08.053. Epub 2021 Aug 11.


A neutral polysaccharide designated as CMDP-1a (molecular mass 9.263 kDa) was isolated from Cucurbita moschata Duch through hot water extraction, ethanol precipitation, and column chromatography. On the basis of methylation, fourier-transform infrared, monosaccharide composition, and one- and two-dimensional nuclear magnetic resonance spectroscopy analyses, the structure of CMDP-1a was determined to be a backbone composed of α-1,4 linked glucopyranosyl residues with α-Glcp residue linkage at backbone C-6. Atomic force microscopy and scanning electron microscopy analyses revealed that CMDP-1a had a spherical conformation in solution. In immunostimulation assays, CMDP-1a promoted the proliferation of RAW 264.7 macrophages and significantly enhanced their pinocytic and phagocytic capacity. Furthermore, CMDP-1a induced the M1 polarization of original macrophages and the conversion of macrophages from M2 to M1, thereby modulating the balance of M1/M2 macrophages. These results indicated that CMDP-1a might be a potential immunomodulator for food purposes.

Keywords: Immunomodulatory activity; Macrophages; NMR; Polysaccharide; Pumpkin; Structure characterization.

MeSH terms

  • Animals
  • Cell Polarity / drug effects
  • Cucurbita / chemistry*
  • Cytokines / genetics
  • Cytokines / metabolism
  • Immunologic Factors / pharmacology*
  • Macrophages / drug effects
  • Macrophages / immunology
  • Magnetic Resonance Spectroscopy
  • Methylation
  • Mice
  • Models, Biological
  • Molecular Weight
  • Monosaccharides / analysis
  • Phagocytosis / drug effects
  • Pinocytosis / drug effects
  • Polysaccharides / isolation & purification
  • Polysaccharides / pharmacology*
  • Polysaccharides / ultrastructure
  • RAW 264.7 Cells
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Spectrophotometry, Ultraviolet
  • Spectroscopy, Fourier Transform Infrared


  • Cytokines
  • Immunologic Factors
  • Monosaccharides
  • Polysaccharides
  • RNA, Messenger