12,13-エポキシ-3α,7α,15-トリヒドロキシトリコテカ-9-エン-8-オン

There are no known antidotes to trichothecene mycotoxins. Treatments are directed at supporting hemopoietic abnormalities, gastrointestinal damage, and skin damage. Administer charcoal as a slurry in case of acute oral exposure. In case of inhalation: Move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with inhaled beta2 agonist and oral or parenteral corticosteroids. In case of eye exposure, Irrigate exposed eyes with copious amounts of room temperature water for at least 15 minutes. In case of dermal exposure, Remove contaminated clothing and wash exposed area thoroughly with soap and water. (A704)

Trichothecenes have multiorgan effects including anoerxia and weight loss, growth retardation, nervous disorders, cardiovascular alterations, immunodepression, hemostatic derangements, skin toxicity, decreased reproductive capacity, bone marrow damage, and alimentary toxic aleukia. (L1948, L1949, A2964)

Unlike many other mycotoxins, trichothecenes do not require metabolic activation to exert their biological activity, instead directly reacting with cellular components. Trichothecenes are cytotoxic to most eukaryotic cells due to their powerful ability to inhibit protein synthesis. They do this by freely moving across the plasma membrane and binding specifically to ribosomes with high-affinity. Specifically, they interfere with the active site of peptidyl transferase at the 3'-end of large 28S ribosomal RNA and inhibit the initiation, elongation or termination step of protein synthesis, as well as cause polyribosomal disaggregation. Protein synthesis is an essential function in all tissues, but tissues where cells are actively and rapidly growing and dividing are very susceptible to the toxins. Additionally, binding to ribosomes is thought to activate proteins in downstream signalling events related to immune response and apoptosis, such as mitogen-activated protein kinases. This is known as ribotoxic stress response. Trichothecenes may also induce some alterations in membrane structure, leading to increased lipid peroxidation and inhibition of electron transport activity in the mitochondria. They can further induce apoptosis through generation of reactive oxygen species. Further secondary effects of trichothecenes include inhibition of RNA and DNA synthesis, and also inhibition of mitosis. (L1948, L1949, A2962, A2963, A2964, A2980)

Trichothecenes are lipophilic and thus easily absorbed through the skin, gut, and pulmonary mucosa. They are metabolized mainly by cytochrome P-450 and trichothecene-specific carboxylesterase activity in the liver, although other tissues such as the kidney, spleen, and intestine also show some metabolic activity. Trichothecenes are metabolically transformed to less toxic metabolites by such reactions as hydrolysis, hydroxylation, de-epoxidation, and glucuronidation. Deoxynivalenol is metabolized mainly to the de-epoxy metabolite. Metabolites are excreted in the urine and feces. (L1910, L1949, A738)

Vomitoxin, also known as deoxynivalenol (DON), is a type B trichothecene, an epoxy-sesquiterpeneoid. Trichothecenes are a very large family of chemically related mycotoxins produced by various species of Fusarium, Myrothecium, Trichoderma, Trichothecium, Cephalosporium, Verticimonosporium, and Stachybotrys. Vomitoxin occurs predominantly in grains such as wheat, barley, oats, rye, and maize, and less often in rice, sorghum, and triticale. The occurrence of deoxynivalenol is associated primarily with Fusarium graminearum (Gibberella zeae) and F. culmorum, both of which are important plant pathogens which cause Fusarium head blight in wheat and Gibberella ear rot in maize. (L1948, L1951)