Trichothecenes

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Chemical structure of trichothecenes

Trichothecenes are a very large family of chemically related mycotoxins produced by various species of fungi , including the genera Fusarium , Myrothecium , Trichoderma , Trichothecium , Cephalosporium , Verticimonosporium, and Stachybotrys . Trichothecenes belong to the sesquiterpene compounds. They were first isolated from the mold Trichothecium roseum by Freeman and Morrison in 1948 and were named after the fungus. The poisonous mushroom Podostroma cornu-damae , which is found in Japan and China, contains six trichothecenes ( satratoxin H , roridin E, verrucarin J and others).

Trichoderma harzianum - Example of a fungus that contains trichothecenes.

The most important structural features that are the reason for the biological activities of the trichothecenes are the 12,13- epoxy ring, the presence of hydroxyl or acetyl groups at suitable positions in the trichothecene core and the structure and position of the side chains . Due to their chemical structure and toxicity, they are divided into four subgroups (types A to D, according to Ueno 1983), with types A and B being the most common. Type B trichothecenes differ from type A by a carbonyl group in C-8.

A distinction is made between simple and macrocyclic trichothecenes. The latter class has a macrocyclic ring in addition to the general, central sesquiterpene ring structure of the simple trichothecenenes.

Trichothecenes have a strong influence on animal and human health e.g. B. because of their immunosuppressive effect, as some of the mold species (e.g. Stachybotrys chartarum ) also release the toxins into the air. Type A trichothecenes (e.g. T-2 toxin , HT-2 toxin , diacetoxyscirpenol) are of particular interest because they are even more toxic than the similar type B trichothecenes (e.g. deoxynivalenol, nivalenol, 3- and 15- acetyldeoxynivalenol ). Their major effects - in connection with their concentration in the environment - reduce feed intake, lead to vomiting and disruption of the immune system. They are absorbed through the skin and food and have a cell-damaging effect. Symptoms of poisoning are vomiting, diarrhea and skin reactions. They can be detected in many different types of grain such as wheat , oats or maize when attacked with different Fusarium species such as F. graminearum , F. sporotrichioides , F. poae , F.langethiae and F. equiseti .

Trichothecenes (including T-2 toxin) have been researched for military purposes in some countries, but this has been abandoned due to their lack of stability against UV light and heat.

proof

A very rough estimate of the concentration of the trichothecent deoxynivalenol in cereals can be made based on the proportion of infected wheat grains. A more precise determination allows the evaluation of the reflection spectra of wheat grains. The most accurate methods are the direct detection of the trichothecenes, for example by gas chromatography or HPLC analysis with coupled mass spectrometry.

Trichothecenes (selection)

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  1. ↑ Trichothecenes Mycotoxins (English) .
  2. ↑ Mycotoxins - Occurrence and Significance. ( Memento from April 10, 2014 in the web archive archive.today )
  3. ↑ Detection of Airborne Stachybotrys chartarum Macrocyclic Trichothecene Mycotoxins in the Indoor Environment. In: Appl. Environ. Microbiol. vol. 71, no. 11, November 2005, pp. 7376-7388.
  4. ↑ M. Beyer, MB Klix, J.-A. Verreet: Estimating mycotoxin contents of Fusarium -damaged winter wheat kernels. In: International Journal of Food Microbiology. 119, 2007, pp. 153-158, doi: 10.1016 / j.ijfoodmicro.2007.07.007 .
  5. ^ M. Beyer, F. Pogoda, FK Ronellenfitsch, L. Hoffmann, T. Udelhoven: Estimating deoxynivalenol contents of wheat samples containing different levels of Fusarium -damaged kernels by diffuse reflectance spectrometry and partial least square regression. In: International Journal of Food Microbiology. 142, 2010, pp. 370-374, doi: 10.1016 / j.ijfoodmicro.2010.07.016 .
  6. ↑ HU Melchert, E. Pabel: Reliable identification and quantification of trichothecenes and other mycotoxins by electron impact and chemical ionization-gas chromatography-mass spectrometry, using an ion-trap system in the multiple mass spectrometry mode. Candidate reference method for complex matrices. In: J Chromatogr A. 1056 (1-2), Nov 12, 2004, pp. 195-199. PMID 15595550
  7. ↑ Stefan Asam, Michael Rychlik: Analysis of Trichothecene Mycotoxins in Grain. (PDF; 19 kB), accessed on April 21, 2013.

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