Augmentation of anti-viral immune responses in flu infected mice by supplementation with a seaweed-derived sulfated polysaccharide, Fucoidan 3427

Description Fucoidan is sulfated polysaccharides found in their viscous component covers surface of brown algae. We previously revealed that fucoidan could augment anti-tumor immune responses and prevent tumor growth and reported that fucoidan from Okinawamozuku (Cladosiphon okamuranus) cooperatively activated innate immune cells which were moderately stimulated with several PRR ligands. The results have been promoting usage of fucoidan as an ingredient for immune-enhancing dietary supplements. In this study, we evaluated the capacity of fucoidan to prevent viral infection. At first, Okinawamozuku-derived fucoidan was intragastrically administered to BALB/c mice by 30, 80, and 240 mg/kg for 14 consecutive days, then, these mice were infected with A/PR/8/34 influenza virus strain and monitored up to 10 days. Whereas the morbidity scores were rapidly increased in the control mice from the 5th day of infection and all the mice died until day 9, the treatment with over 80 mg/kg of fucoidan ameliorated the symptoms and protected from death with the flu infection. Next, we evaluated the anti-viral effect of 80 mg/kg fucoidan and revealed that fucoidan significantly inhibited viral propagation in the lungs during 3 days after infection. Furthermore, the oral administration of fucoidan induced effective anti-viral responses as represented by enhanced expression of type I and II interferon in the lung. These results clearly indicated usefulness of dietary fucoidan in prevention of flu infection.