Abstract

This paper describes the natural occurrence of the toxin, cylindrospermopsin, in two species of cyanobacteria found in Australia. The structure and chemical properties of this compound are described along with a nontoxic analog of cylindrospermopsin. The results of both intraperitoneal (IP) and oral dosing of mice show that hepatotoxicity is the main effect of cylindrospermopsin in vivo, but that a thrombohemorrhagic phenomenon is observed in a proportion of dosed animals. It has been shown that the toxin can be metabolized in vivo and that a bound metabolite occurs in the liver. Cytotoxicity experiments using cell cultures show that cylindrospermopsin is more cytotoxic to isolated rat liver hepatocytes than to other cell types. Risk assessment calculations show that guideline values for cylindrospernopsin in drinking water should lie in the low microgram per liter range.