Effects of structural peculiarities of carrageenans on their immunomodulatory and anticoagulant activities

Biological activity of five carrageenan types - kappa, kappa/beta, kappa/iota, lambda and new type - iks - isolated from the most abundant species belonging to Gigartinaceae and Tichocarpaceae collected from the Pacific coast was investigated. The ability of carrageenans to influence on the cytokine production by human cells is greatly dependent on concentration and structure of polysaccharides. At high concentrations all types of carrageenans increased the level of pro-inflammatory IL-6 and TNE-alpha, while at low concentration (1-10 ng/mL) their activity was insignificant. All types of carrageenans induced the secretion of anti-inflammatory IL-10 in dose-dependent manner. Hybrid kappa/beta-carrageenan showed fairly high activity independent on concentration. At low concentrations (10 ng/mL) its activity was more than that of LPS. The structural analysis of polysaccharides suggests that additional sulphate ester residue of lambda-carrageenan increases the concentration of calcium in macrophage cytoplasm and may have an important role in the activation process of the formation of active oxygen forms. Kappa/iota carrageenan possessed for the potential anticoagulant activity, which was extremely strong in low concentration. These results suggest that the immunomodulation and anticoagulant activity of carrageenans depends on the monosaccharide composition of polysaccharides, number, position and distribution of sulphate groups along galactan chain. (C) 2011 Elsevier Ltd. All rights reserved.