Cylindrospermopsin, a cyanobacterial alkaloid: Evaluation of its toxicologic activity

This paper describes the natural occurrence of the toxin, cylindrospermopsi n, in two species of cyanobacteria found in Australia. The structure and ch emical properties of this compound are described along with a nontoxic anal og of cylindrospermopsin. The results of both intraperitoneal (IP) and oral dosing of mice show that hepatotoxicity is the main effect of cylindrosper mopsin in vivo, but that a thrombo-hemorrhagic phenomenon is observed in a proportion of dosed animals. It has been shown that the toxin can be metabo lized in vivo and that a bound metabolite occurs in the liver. Cytotoxicity experiments using cell cultures show that cylindrospermopsin is more cytot oxic to isolated rat liver hepatocytes than to other cell types. Risk asses sment calculations show that guideline values for cylindrospermopsin in dri nking water should lie in the low microgram per liter range.