Review: Biological effects of organic arsenic compounds in seafood

This review describes the results of our recent experiments concerning the in vitro biological effects of water‐soluble organic arsenic compounds contained in seafood in murine immune effector cells using synthetic pure materials. A dimethyl organic arsenic compound in seaweed, viz. an arsenosugar, was weakly cytotoxic in murine alveolar macrophages during a 72 h incubation (50% lethal concentration in vitro, LC50 = 8 mmol dm−3); conversely, it increased the cell viability of peritoneal macrophages at an optimal dose of 5 mmol dm−3. Trimethyl arsenic compounds in marine animals, arsenocholine and arsenobetaine, were less toxic in murine splenocytes, thymocytes, Peyer's patch lymphocytes, peritoneal macrophages and alveolar macrophages in vitro, even over 10 mmol dm−3. Interestingly, they significantly increased the cell viability of immature bone marrow cells at doses over 100 µmol dm−3, and induced the maturation of bone marrow cells especially into granulocytes. The tetramethyl arsenic compound, tetramethylarsonium hydroxide, isolated from some lower marine animals had no in vitro cytolethality on murine immune effector cells. Taken together, organic arsenic compounds in seafood are not very toxic in living systems.