A polysaccharide from Umbilicaria yunnana: Structural characterization and anti-inflammation effects

A polysaccharide JUYP was isolated and purified from Umbilicaria yunnana. The detailed structure of JUYP was studied using gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR), methylation-GC-MS, nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). A homogeneous polysaccharide JUYP was obtained with the yield of 21.2% and average molecular weight (Mw) of 577 kDa. Monosaccharide composition analysis indicated that JUYP was composed of glucose, galactose and mannose with a molar ratio of 2.3:1:0.7. Structural analyses demonstrated that the dominate components in JUYP were 6-β-D-Glcp, and other sugar residues included 2,4-β-D-Manp and T-β-D-Galf. TEM images further revealed JUYP was a linear branched molecule with entangled chains. Based on the anti-inflammatory assays, 1 μg/mL of JUYP exhibited good inhibitory effects on TNF-α, IL-6, IL-1β and COX-2 mRNA expressions in LPS-stimulated RAW 264.7 cells, while the inhibitory effects (87.8% for mRNA, 55.89% for protein) of JUYP on IL-1β expressions were more significant than that of dexamethasone (DXMS, 61.6% for mRNA, 35.15% for protein) (p<0.01).