Abstract
We examined the effects of fucoidans differing in molecular weight and composition extracted from Cladosiphon okamuranus Tokida and Fucus vesiculosus on lymphocyte-mediated immunological function and the proliferative responses of normal lymphocytes and leukemic cells. Fucoidan from Fucus vesiculosus, which contains a low proportion of uronic acid and a high proportion of sulfate, strongly inhibited the proliferative responses of normal activated lymphocytes and leukemic cells and induction of apoptosis. In contrast, fucoidan from Cladosiphon okamuranus which contains a higher proportion of uronic acid and a lower proportion of sulfate, exhibited both mitogenic activity against normal T lymphocytes and efficient production of inflammatory cytokines from macrophages at low concentrations. These fucoidans showed less inhibitory activity against leukemic cells and activated lymphocytes. Our results suggest that the biological properties of fucoidans as either immuno-stimulators or apoptosis inducers may be dependent on molecular weight, or differences in the components of polysaccharides.
