Biological Consequences of Fumonisins

[Synopsis] Fumonisins are a series of mycotoxins produced primarily by Fusarium moniliforme, a ubiquitous contaminant of corn (maize), and F. proliferatum, a common contaminant of sorghum and rice afflicted with Fusarium sheath rot disease. Fumonisins are presumed to be tumor promoters because of the bioassay used to guide their initial isolation. Fumonisin B_1 (FB_1) has been shown to cause leukoencephalomalacia in horses, pulmonary edema in swine and cancer in rats and mice. Fumonisins are structural analogs of AAL-toxins produced by Altemaria alternata, and the putative second messenger sphingosine. Fumonisins became a food safety concern when they were demonstrated to be common contaminants of corn-derived foods and feeds. In vitro studies of mammalian cytotoxicity and phytotoxicity showed that many changes can be made in the FB_1 structure without loss of biological activity. Studies on the fate of FB_1 during food processing were initiated because of concern that FB_1 apparently destroyed during cooking of corn-derived foods may be converted to other toxic forms. During cooking radiolabeled FB_1 became covalently bound to corn proteins through side chains in a manner which may allow its release in a toxic form on digestion. Further research is needed to determine the threat to food safety posed by protein-bound mycotoxins