Deamination of Fumonisin B1 and Biological Assessment of Reaction Product Toxicity

Fumonisin B1, a potent mycotoxin found in grain, has been resistant to degradation and detoxification by a variety of methods, including milling, fermentation, ammoniation, and ozonation. The primary amine of this compound contributes significantly to its toxicity; therefore, the major aim of this research was to remove this moiety via diazotization. In this study, fumonisin B1 was deaminated in aqueous solution under conditions of acidic pH and low temperature (pH 1.0 and 5 °C) with the addition of NaNO2. The concentration of fumonisin B1 in the solution was analyzed by HPLC using o-phthaldialdehyde to derivatize the primary amine. Progress of the reaction was monitored as a loss of the derivatized peak as observed by HPLC with fluorescence detection. TLC analysis showed the disappearance of fumonisin B1 following diazotization. Further, TLC displayed at least four reaction products that were not primary amines. Matrix-assisted laser desorption/ionization mass spectrometry coupled with time-of-flight analysis of the diazotization products also showed a diminished amount of authentic fumonisin B1 and allowed identification of a product formed by the replacement of the primary amine with a hydroxyl group. The adult Hydra attenuata bioassay indicated a marked decrease in the toxicity of the products in comparison to parent fumonisin B1. Optimization of this reaction could result in a rapid and practical method for the reclamation of fumonisin B1-contaminated feeds.