Current research on mycotoxins: Fumonisins

Currently, the most active areas of research on established mycotoxin groups (notably aflatoxins, tricothecenes and ochratoxins) involves cloning and characterization of biosynthesis genes, and elucidating the role of mycotoxins in the etiology of important diseases. The most recently discovered group of mycotoxins, first identified in 1988, are the fumonisins, the most abundant of which is FB₁. They are sphingosine analogs which exert all or most of their effects by inhibition of sphingolipid biosynthesis. FB₁ is cytotoxic, phytotoxic and causes equine leucoencephalomalacia and porcine pulmonary edema. However, the major reason for interest in fumonisins is their possible role as environmental tumor promoters in causing human cancer. Because the producing organism, F. moniliforme, is a ubiquitous contaminant of corn, and the toxins are stable enough to at least partially survive most food processing techniques, readily detectable amounts contaminate most corn-derived products available for human consumption. Studies on structure-activity relationships among fumonisins indicate that biological activity is retained through most structural changes, including loss of the side chains which constitute up to half the molecular weight. These observations led us to investigate the fate of radiolabeled FB₁ during food processing. Preliminary studies indicate a substantial amount of FB₁ binds covalently to protein and starch in ways that may result in release of an active form upon digestion.