Structural characterization of a pectic polysaccharide from laoshan green tea and its inhibitory effects on the production of NO, TNF-<i>α</i> and IL-6

A novel pectic polysaccharide, named GTPS3-1, was isolated and purified from Laoshan green tea polysaccharide (GTPS) through DEAE Sepharose Fast Flow and Sephacryl S-300 columns, its structure was characterized and its anti-inflammatory activity was explored. GTPS3-1, with a molecular weight of 26.05 kDa, was mainly composed of galacturonic acid, galactose, rhamnose and arabinose in a molar ratio of 4.72:2.5:1.68:1 on the basis of monosaccharide composition. Structural analysis results revealed that GTPS3-1 was a highly branched pectin consisting of →3)-Galp-(1→, →2)-Rhap-(1→, →3,5)-Araf-(1→, →3)-Rhap-(1→, GalpA-(1→, →3,4)-Galp-(1→, →4)-GalpA-(1→, →5)-Araf-(1→, →2,4)-Rhap-(1→, Rhap-(1→ and Araf-(1→ according to FT-IR, methylation and NMR analyses. In addition, GTPS3-1 inhibited the production of NO, TNF-α and IL-6 in a dose-dependent manner, which resulted in the amelioration of inflammatory injury in LPS-induced RAW 264.7 cells. These results would provide a theoretical basis for practical application of the novel polysaccharide as an anti-inflammatory adjuvant.