Isolation, purification, structural analysis and biological activities of water-soluble polysaccharide from Glehniae radix

A new polysaccharide named GRP (Glehniae radix polysaccharide) was isolated and purified from Glehniae radix by hot water extraction, ethanol precipitation, anion-exchange and gel-filtration chromatography. GRP was homogeneous, with a molecular weight of 1.33×104Da, as determined by high-performance size-exclusion chromatography-refractive index detector analysis. Its structural characteristics were investigated and elucidated by methylation analysis, gas chromatography mass spectrometry, Fourier transform infrared and nuclear magnetic resonance spectroscopy. Based on obtained data, GRP was found to be α‑d‑glucan containing (1→6)-linked and (1→3)-linked backbone with a branch of one (1→6)-linked and terminal glucoses submitting at the C-4 position every fourteen residues. The biological activities of GRP upon proliferation of splenic lymphocyte, RAW264.7 cells and A549 cell, and production of nitric oxide (NO) were investigated in vitro. The results showed that GRP exhibited inhibition against A549 cells proliferation and NO production in RAW264.7 cells, and displayed promotion for proliferation of mouse spleen lymphocytes and RAW264.7 cells, which suggested that GRP may have potential immunoregulation, anti-inflammatory and anti-tumor activity.