Trichothecene mycotoxins diacetoxyscirpenol

Swanson, S.P. et ah. Metabolism of three trichothecene mycotoxins, T-2 toxin, diacetoxyscirpenol and deox5mivalenol, by bovine rumen microorganisms, J. Chromatogr., 414, 335, 1987. 

Trichothecene mycotoxins are a group of sesquiterpenoid mycotoxins produced by fungi from the Fusarium family. There are four types Type-B such as nivalenol differs from Type-A such as diacetoxyscirpenol by the presence of the keto-group in the C8 position. Type-C has an additional epoxide group, and Type-D are macrocyclic trichothecenes. Human and animal toxicoses by these toxins have been dne to the consnmption of contaminated grain. The structure of some of the Type-A and Type-B componnds is shown in Table 14.2. 

The separation of trichothecene mycotoxins from biological materials by UV absorption or fluorescence absorption is difficult, but the most suitable analytical methods are gas chromatography mass spectrum analysis. Recently, radioimmunoassay and enzyme linked immunosorbant assay have been developed for T-2 toxin and diacetoxyscirpenol (DAS) and deoxyverrucarol, which are highly sensitive as compared to other biological and chemical methods. 

The need for detoxification of commodities contaminated by trichothecene mycotoxins has been known to be of significance by Bamburg et al. (1971). The yellow rain controversy (Mirocha, 1983) has made the interest in trimethecenes world-wide. Stahr, et al. (1985) has shown that T-2 toxin and diacetoxyscirpenol can be volatilized and trapped for analysis. Thermally removing the toxins from commodities was attempted in this work. 

TRICHOTHECENE MYCOTOXINS. A family of structurally related poisonous substances produced by various species of fungi, especially Acremorium (Cephalosporium), Fusarium, Myrothe-cium, Stachybotrys, Trichderme, and Verticumonosporium. Tri-chothecene mycotoxins are toxic to humans because they inhibit cellular protein synthesis. Prominent examples are deoxynivalenol (sometimes referred to as vomitoxin because it induces vomiting), diacetoxyscirpenol, HT-2, nivalenol, and T-2. These five toxins gained some notoriety in the so-caUed yellow rain events in Southeast Asia because of allegations that they were associated with Soviet-inspired use of chemical weapons (CW). 

Contamination occurs primarily in wheat, barley, rye, and maize. Type A trichothecenes include mainly T-2 toxin, HT-2, and diacetoxyscirpenol (DAS) mycotoxins of the group B include mainly 4-deoxynivalenol (DON), commonly known as vomitoxin, and nivalenol (NIV). Toxic effects include nausea, vomiting, visual disorder, vertigo, throat irritation, and feed refusal in farm animals. The most toxic is T-2, followed by DAS and NIV, with DON being the least toxic in acute toxicity studies but the most widespread in grains worldwide and therefore the most studied. Issues related to chemical and physical data, occurrence, toxicity, absorption, distribution, and metabolism of trichothecenes are reviewed in WHO (89) and IARC (34). Physicochemical data for some selected Fusarium toxins is given by Sydenham et al. (90). The molecular structures of the main trichothecenes are shown in Fig. 9. 

A potentially important application area for capillary SFC and SFC-MS is in the analysis of thermally labile molecules not readily amenable to gas chromatography, such as mycotoxins of the trichothecene group (48,49). Figure 14 shows a fast separation of four trichothecenes on a short 0.8 m x 25 pm column at 100 C with supercritical CO2 as the mobile phase. Diacetoxyscirpenol (DAS) and T-2 toxin are easily resolved while the two macrocyclic compounds, roridin A and verricarin J, are not well separated. However, even this level of separation is often sufficient given a highly selective detector such as the mass spectrometer. Application of SFC-MS to these compounds is described in detail elsewhere ( ). 

Methods exist for many matrix/mycotoxin combinations including patulin in apple juice using atmospheric pressure photoionization, zearalenone and its metabolites in fish tissue and porcine urine, muscle, and liver tissues using electrospray ionization, trichothecenes (T-2 toxin, HT-2 toxin, acetyl T-2 toxin, diacetoxyscirpenol, neosolaniol, and mono-acetoxyscirpenol) in grain using atmospheric pressure chemical ionization, and trichothecenes (T-2 toxin, HT-2 toxin, deoxynivalenol, nivalenol), zearalenone and its metabolites (a- and jS-zearalenol and a- and jS-zearalanol) in eggs. 

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