Toxicity, metabolism, and impact of mycotoxins on humans and animals.

Trichothecene mycotoxins are found worldwide in cereal grains and in animal feed and human food produced from contaminated grains, which creates a food safety risk. Chemical and biological reactions are being evaluated for their usefulness in transforming trichothecene mycotoxins into other, less toxic, compounds for improved safety in food chains. Trichothecene transformation reactions discovered to date include alkalization, oxidation, reduction, hydrolysis, hydration and conjugation. Many of these reactions can change the structures of selected mycotoxins but not necessarily reduce their toxicity. More emphasis should be placed on understanding detoxification reactions, the toxicity of transformation products, and enzymes responsible for the transformations.

Chemical and biological transformations for detoxification of trichothecene mycotoxins in human and animal food chains: a review

To date, the use of biomarkers has become generally accepted. Biomarker-driven research has been proposed as a successful method to assess the exposure to xenobiotics by using concentrations of the parent compounds and/or metabolites in biological matrices such as urine or blood. However, the identification and validation of biomarkers of exposure remain a challenge. Recent advances in high-resolution mass spectrometry along with new analytical (post-acquisition data-mining) techniques will improve the quality and output of the biomarker identification process. Chronic or even acute exposure to mycotoxins remains a daily fact, and therefore it is crucial that the mycotoxins' metabolism is unravelled so more knowledge on biomarkers in humans and animals is acquired. This review aims to provide the scientific community with a comprehensive overview of reported in vitro and in vivo mycotoxin metabolism studies in relation to biomarkers of exposure for deoxynivalenol, nivalenol, fusarenon-X, T-2 toxin, diacetoxyscirpenol, ochratoxin A, citrinin, fumonisins, zearalenone, aflatoxins, and sterigmatocystin.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12367

Mycotoxin Biomarkers of Exposure: A Comprehensive Review.

Trichothecenes comprise a large family of structurally related toxins mainly produced by fungi belonging to the genusFusarium. Among trichothecenes, type A and type B are of the most concern due to their broad and highly toxic nature. In order to addressstructure-activity relationships (SAR) of trichothecenes, relationships between structural features and biological effects of trichothecenemycotoxins in mammalian systems are summarized in this paper. The double bond between C-9-C-10 and the 12,13-epoxide ringare essential structural features for trichothecene toxicity. Removal of these groups results in a complete loss of toxicity. A hydroxylgroup at C-3 enhances trichothecene toxicity, while this activity decreases gradually when C-3 is substituted with either hydrogen or anacetoxy group. The presence of a hydroxyl group at C-4 promotes slightly lower toxicity than an acetoxy group at the same position. Thetoxicity for type B trichothecenes decreases if the substituent at C-4 is changed from acetoxy to hydroxyl or hydrogen at C-4 position.The presence of hydroxyl and hydrogen groups on C-15 decreases the trichothecene toxicity in comparison with an acetoxy group attachedto this carbon. Trichothecenes toxicity increases when a macrocyclic ring exists between the C-4 and C-15. At C-8 position, anoxygenated substitution at C-8 is essential for trichothecene toxicity, indicating a decrease in the toxicity if substituent change fromisovaleryloxy through hydrogen to the hydroxyl group. The presence of a second epoxy ring at C-7-C-8 reduces the toxicity, whereas epoxidationat C-9-C-10 of some macrocyclic trichothecenes increases the activity. Conjugated trichothecenes could release their toxic precursorsafter hydrolysis in animals, and present an additional potential risk. The SAR study of trichothecenes should provide some crucialinformation for a better understanding of trichothecene chemical and biological properties in food contamination.

Y. Ueno

Papers

The cytochrome P-450-dependent hydroxylation of T-2 toxin in various animal species