Characterization and anti-allergic effect of a polysaccharide from the flower buds of Lonicera japonica

A water-soluble polysaccharide (LJP-1), with a molecular weight of 1.8 × 105 Da, was isolated from the flower buds of Lonicera japonica. Gas chromatography (GC) analysis showed that the LJP-1 was mainly composed of d-glucose and a small amount of d-arabinose. On the basis of methylation analysis, LJP-1 had the backbone chain mainly consisting of 1,6-linked Glc and 1,3,6-linked Glc, which was terminated with 1-linked Ara residues at the O-3 position of 1,3,6-linked Glc in a relative molar ratio of 2.9:1:0.9. The anti-allergic effect of LJP-1 was evaluated on allergic contact dermatitis (ACD) induced by picryl chloride (PC) in mouse ear. Similar to prednisolone, orally administrated LJP-1 (20, 40 and 80 mg/kg) potently inhibited the PC-induced ACD, leading to substantial reductions in ear thickness, serum level of IgE and histamine, as well as tissue TNF-α. These results demonstrate that treatment with LJP-1 may be effective for preventing the development of PC-induced ACD.