Structural characterization of a pectin-like polysaccharide from Clematis chinensis Osbeck and its anti-rheumatoid...

Clematis chinensis Osbeck is a traditional Chinese medicine to treat rheumatic arthritis (RA). We hypothesized that C. chinensis polysaccharide, as a bioactive ingredient, might have the anti-RA function. However, the structure and bioactivity of C. chinensis polysaccharides are less explored. A pectin-like polysaccharide CCPB-2-2 was isolated from C. chinensis root. The putative chemical structure of CCPB-2-2 was characterized through monosaccharide composition, uronic acid reduction, partial acid hydrolysis, methylation reaction, and nuclear magnetic resonance spectroscopy. CCPB-2-2 was composed of the RG-I domain of the pectin moiety and the non-pectin moiety with a backbone with →3)-β-D-Galp-(1→, →6)-β-D-Galp-(1→, →4)-α-D-GlcAp-(1→, →4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, →4)-β-D-Galp-(1→, and →3,6)-α-D-Manp-(1→ residues. Moreover, the anti-RA activity of CCPB-2-2 was evaluated in MH7A cells. CCPB-2-2 could inhibit lipopolysaccharide-induced MH7A cell proliferation, down-regulate the expression of pro-inflammatory factors (interleukin-6, interleukin-8, and interleukin-1 beta) and matrix metalloproteinase genes (matrix metallopeptidase 1 and matrix metallopeptidase 3), regulate apoptosis proteins (B-cell lymphoma-2-associated X and B-cell lymphoma-2) and inhibit cell migration. In conclusion, C. chinensis polysaccharide CCPB-2-2 exhibited great potential as a drug candidate for the treatment of RA, which is worth of further research and development.