In the present study, a novel water-soluble polysaccharide (DNP-1) was isolated and purified from the root of Duhaldea nervosa via column chromatography. Structural analyses indicated that DNP-1 had a linear backbone consisting of (2→1)-linked β-D- fructofuranosyl residues, ending with a (2→1) bonded α-D-glucopyranose. DNP-1 was a homogeneous polysaccharide with an average molecular weight of 3.7 kDa. Furthermore, the anti-inflammatory activity of DNP-1 was investigated in vitro. The concentration of pro-inflammatory cytokines, including NO, TNF-α, MCP-1, IL-2, and IL-6, in the DNP-1 treatment group was suppressed in LPS-induced RAW 264.7 cells. DNP-1 was able to improve inflammatory injury by inhibiting the secretion of pro-inflammatory cytokines. These investigations into this polysaccharide from the root of Duhaldea nervosa provide a scientific basis for the further development of this plant. The results indicate that this Duhaldea nervosa polysaccharide could be used as a potential natural source for the treatment of inflammatory injury.
Keywords: DNP−1; Duhaldea nervosa; RAW 264.7 cells; anti-inflammatory activity; isolation; polysaccharide; roots; structural characterization.