Panax quinquefolius (North American ginseng) cell suspension culture as a source of bioactive polysaccharides: Immunostimulatory activity and characterization of a neutral polysaccharide AGC1

Int J Biol Macromol. 2019 Oct 15;139:221-232. doi: 10.1016/j.ijbiomac.2019.07.215. Epub 2019 Jul 31.

Abstract

In this study, we propose the use of a plant tissue culture-based system for the production of polysaccharides with consistent chemical characteristics and reduced endotoxin content. Polysaccharides were isolated from suspension cultures of Panax quinquefolius (American ginseng), a widely used medicinal herb. A neutral fraction, AGC1, purified by anion exchange and size exclusion chromatography, displayed immunostimulatory activity in vitro and ex vivo. AGC1 (average molecular weight: 5.2kDa) was predominantly composed of galactose (>60%) along with the presence of several other neutral sugars such as arabinose, xylose, glucose, mannose and rhamnose in minor amounts. The major glycosidic linkages were found to be 3-Galp (48.5%), 3,6-Galp (10.2%), t-Galp (5.2%), 6-Galp (4.4%), 4-Glcp (5.7%), 4-Arap/5-Araf (4.0%) and t-Araf (4.5%). AGC1 significantly (p<0.05) stimulated the expression of a range of proinflammatory mediators in RAW 264.7 murine macrophages such as IL-6, TNF-α, MCP-1 and GM-CSF. Additionally, AGC1 treatment of RAW 264.7 cells stimulated NOS2 gene expression, leading to increased levels of iNOS and downstream NO. Consistent with this, AGC1 was able to act as an immunostimulant in primary murine splenocytes, enhancing cell proliferation, as well as NO and TNF-α production. Our results also indicate the partial role of NF-κB pathway in the immunostimulatory response.

Keywords: Immunomodulation; NOS2 reporter; Suspension culture polysaccharides.

MeSH terms

  • Animals
  • Cells, Cultured
  • Culture Media, Conditioned / chemistry*
  • Culture Media, Conditioned / pharmacology*
  • Cytokines / metabolism
  • Immunologic Factors / chemistry
  • Immunologic Factors / pharmacology
  • Immunomodulation / drug effects
  • Macrophages / drug effects
  • Macrophages / immunology
  • Macrophages / metabolism
  • Mice
  • Molecular Weight
  • Nitric Oxide / metabolism
  • Panax / chemistry*
  • Panax / cytology
  • Panax / metabolism
  • Phytochemicals / chemistry*
  • Phytochemicals / isolation & purification
  • Phytochemicals / pharmacology*
  • Plant Extracts / chemistry
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology
  • Polysaccharides / chemistry*
  • Polysaccharides / isolation & purification
  • Polysaccharides / pharmacology*
  • RAW 264.7 Cells

Substances

  • Culture Media, Conditioned
  • Cytokines
  • Immunologic Factors
  • Phytochemicals
  • Plant Extracts
  • Polysaccharides
  • Nitric Oxide