Ecklonia cava fucoidan has potential to stimulate natural killer cells in vivo

Fucoidan is a sulfated polysaccharide, derived from various marine brown seaweeds, that has immunomodulatory effects. In this study, we analyzed the effects of five different fucoidans, which were extracted from Ascophyllum nodosum, Undaria pinnatifida, Macrocystis pyrifera, Fucus vesiculosus, and Ecklonia cava, on natural killer (NK) cell activation in mice. Among these, E. cava fucoidan (ECF) promoted an increase in the number of NK cells in the spleen and had the strongest effect on the activation of NK cells. Additionally, we observed that DC stimulation was required for NK cell activation and that ECF had the most potent effect on splenic dendritic cells (DC). Finally, ECF treatment effectively prevented infiltration of CT-26 carcinoma cells in the lungs of BALB/c mice in an NK cell dependent manner. Collectively, these results suggest that ECF could be a suitable candidate for enhancing NK cell-mediated anti-cancer immunity.