Aflatoxin B1 (AFB1) is a class 1 carcinogen and a common food contaminant worldwide. It is also a major cause of the development of hepatocellular carcinoma (HCC), and is estimated to play a causative role in up to 28% of all HCC cases. Existing strategies to reduce AFB1 exposure are limited and thus, many people are exposed to uncontrollable levels of AFB1. Our study aims to: 1) develop a new chemical treatment process to modify AFB1 into a non-carcinogenic form using benign, dietary reagents and 2) verify that these new products have reduced genotoxicity. Our treatment strategy targets the mutagenic site of the AFB1 molecule, the 8,9-double bond, by adducting it to selected amino acids. Identification and quantification of aflatoxins was carried out using high performance liquid chromatography-electrospray ionization-time of flight mass spectrometry (HPLC-ESI-TOFMS). Optimization of AFB1 hydration was carried out by incubating in various organic acids as well as increasing temperature. Newly formed AFB2a was introduced to alkaline solutions containing individual amino acids to form adducts. Products were identified based on changes in retention times and accurate mass values. A combination of citric and phosphoric acid along with individual amino acids was found to be the most effective while forming a singular product. Accurate mass measurements, fragmentation patterns, and nuclear magnetic resonance (NMR) data of AFB2a-amino acid adducts suggest a different chemical structure than previously proposed. AFB2a-arginine was chosen as the top detoxification candidate due to no significant breakdown in simulated digestive fluids, microsomal incubations, high polarity, and a 10,000-fold decrease in its octanol-water partition coefficient compared to AFB1. Genotoxicity was evaluated using the SOS-Chromotest and Ames’ test in which AFB2a-arginine has shown a complete abolishment of genotoxicity. Additionally, interactions between these toxins and DNA were evaluated by identifying the formation of base pair adducts using mass spectrometry. Results show clear adduct formation with AFB1 while AFB2a-Arg was completely unreactive. Together the data support that when adducted to arginine, AFB1 loses its mutagenicity. In conclusion, this study has identified a novel structure of the AFB2a-arginine which can be formed with compounds that are safe to introduce to foods meant for human consumption.

Protective toxicokinetic and toxicodynamic changes associated with aflatoxin B1 detoxification

254th National Meeting (2017)

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