Structural identification and immunostimulating activity of a Laminaria japonica polysaccharide.

In the present study, a new water-soluble polysaccharide (LJP-11) was obtained from Laminaria japonica by anion exchange DEAE-cellulose chromatography and Sephacryl S-500 chromatography. The average molecular weight of this polysaccharide was estimated to be about 2.89 × 10 6 Da by high performance liquid chromatography system. Gas chromatography showed that LJP-11 was composed of arabinose, mannose and glucose in a molar ratio of 1.0:1.16:6.33. LJP-11 contains a long backbone consisting of (1→4)-β- d -Glc p Ac, (1→4)-α- d -Glc p , (1→6)-β- d -Glc p and (1→3,6)-α- d -Man p . The 1-linked β- l -Ara f was linked to the C-6 of (1→3)-α- d -Man p and the sulfate group was attached to the C-4 of (1→6)-β- d -Glc p . Pharmacological tests displayed that LJP-11 can stimulate macrophages to release NO, IL-6, TNF-α and IL-10 as well as the up-regulation of their gene expressions, indicating LJP-11 has beneficial effects on immunostimulation. Moreover, LJP-11 exhibited positive effects on the translocation of NF-κB p65 from cytoplasm to nucleus and the phosphorylation of IκBα, ERK1/2, JNK1/2 and P38 in macrophages. These results suggested that the activation of MAPK and NF-κB signaling pathways is one of the mechanisms responsible for the immunostimulating activity of LJP-11. [ABSTRACT FROM AUTHOR]