A 4-week repeated oral dose toxicity study of fucoidan from the Sporophyll of Undaria pinnatifida in Sprague–Dawley rats

Fucoidan is extracted from brown seaweeds, which can have anti-coagulant, antithrombotic, antitumor, and antiviral activities. However, detailed studies on the toxicology of fucoidan have not been performed. Here we tested the toxicity of fucoidan in Sprague–Dawley rats. Fucoidan (1350 mg/kg bw/day for 4 weeks) did not induce statistically significant differences in groups matched by gender with respect to body weight, ophthalmoscopy, urinalysis, hematology, and histopathology. Fucoidan did not change prothrombin time or activated partial thromboplastin time, indicating an inability to change blood clotting. This study demonstrated that fucoidan is not toxic under this administration paradigm.