Acetylation/Deacetylation Reactions of T-2, Acetyl T-2, HT-2, and Acetyl HT-2 Toxins in Bovine Rumen Fluid in Vitro

A tritiated preparation of the trichothecene mycotoxin, T-2 toxin, underwent both acetylation and deacetylation reactions when incubated with bovine rumen fluid in vitro. Products from incubations of T-2 in rumen fluid included acetyl T-2, HT-2, and acetyl HT-2. Direct studies with tritiated samples of each of these metabolites confirmed their relatively facile interconversion in the rumen. Studies with [³H]HT-2 under conditions of inhibited esterase activity (added diisopropyl fluorophosphate) showed that acetylation is preferred at C-3 vs. C-4. Studies with [³H]acetyl T-2 indicated that deacetylation similarly occurs with greater rapidity at C-3. There were no indications that ester hydrolysis of these trichothecenes occurred at C-8 or C-15 or that they were subjected to epoxide reduction reactions. These data suggest that acetylation of T-2 and other trichothecenes in the rumen in situ may ultimately result in the absorption of more lipophilic metabolites whose toxicological and residual properties are at present unknown.