Deamination of Fumonisin B sub(1) and Biological Assessment of Reaction Product Toxicity

Fumonisin B sub(1), 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 B sub(1) was deaminated in aqueous solution under conditions of acidic pH and low temperature (pH 1.0 and 5 degree C) with the addition of NaNO sub(2). The concentration of fumonisin B sub(1) 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 B sub(1) 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 B sub(1) 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 B sub(1). Optimization of this reaction could result in a rapid and practical method for the reclamation of fumonisin B sub(1)-contaminated feeds.