Oligosaccharides of κ/β-carrageenan from the red alga Tichocarpus crinitus and their ability to induce interleukin 10

The structural peculiarities of oligosaccharide mixture (LMW-carr) obtained by mild acid hydrolysis of κ/β-carrageenan from the red alga Tichocarpus crinitus were investigated by negative-ion MALDI-TOFMS. An analysis suggested the presence of β-, ι- and γ-carrageenan (the precursor of β-carrageenan) blocks. MS/MS analysis revealed the presence of β/ι-hybrid structures, which co-existed in the hydrolysis mixture along with κ/β-tetrasaccharide. The effect of source polysaccharide (400 kDa) and purified oligosaccharides LMW-carr (1.7 kDa) on the production of anti-inflammatory cytokine IL-10 was examined in experiments in vivo and ex vivo. Both samples of carrageenan stimulated induction of IL-10 in human and in mice blood cells that depended on their molecular weights. LMW-carr (administered orally) induced more IL-10 in vivo production than source polysaccharide. The ex vivo cytokine-induced activity of HMW-carr did not depend on its concentration. LMW-carr caused strong increase in the level of cytokines at high concentration (10 μg mL⁻¹).