Chemical synthesis of the trichothecenes

Toxicology of novel macrocyclic trichothecenes, baccharinoid B4, myrotoxin B, and roritoxin B

Baccharinoid B4, Myrotoxin B and Roritoxin B, some recently identified macrocyclic trichothecenes, were tested in Swiss mice with respect to their toxicity after oral and topical application. For oral dosing, the mycotoxins were dissolved in propylene glycol, and doses from 0 to 8.0 mg/kg body weight (BW) were employed. For topical application, toxins were dissolved in DMSO. A dose of 40 mg/kg BW was applied, except for Roritoxin B, where a dose of 10 mg/kg BW was also utilized. Animals were observed until death, or until 14 days after application and histopathological examinations were performed. It was found that Baccharinoid B4 was only moderately toxic, but this macrocyclic trichothecene appeared to exert its toxicity particularly on the intestine. Myrotoxin B was found to be quite toxic, and Roritoxin B was determined to be the most potent and toxic macrocyclic trichothecene of the three investigated. Oral administration of Roritoxin B resulted in death of 70-90% of mice at doses up to 1.0 mg/kg BW, and topical application of 10 or 40 mg/kg BW caused 100% death within 18 hours after application.

Mass spectral investigations on trichothecene mycotoxins. I. Application of negative ion chemical ionization techniques for the simultaneous and accurate analysis of simple trichothecenes in picogram levels

A fast and sensitive gas chromatographic/negative ion chemical ionization mass spectrometric method for the simultaneous detection and quantification of several simple trichothecene mycotoxins and related molecules with good precision has been developed. The method consists of the conversion of the polar trichothecenes into their volatile and stable heptafluorobutyryl esters, followed by gas chromatographic/mass spectrometric analysis of the derivatives. The derivatives were ionized under chemical ionization conditions and the negative ions were monitored. The samples were screened for the presence of trichothecenes by monitoring one characteristic ion by selected ion monitoring for each analyte. The detected compounds were confirmed by monitoring 5-6 characteristic ions by selected ion monitoring whenever the amount of analyte present was insufficient to obtain a full scan negative ion chemical ionization mass spectrum. Two semi-synthetic trichothecenes, 4-deoxyverrucarol and 16-hydroxyverrucarol, were investigated and found to be adequate internal standards both for detection and quantification of these toxic compounds. Femtogram and low picogram (1-5 pg) quantities of these compounds could be detected and confirmed, respectively, by this procedure. A short clean-up procedure using Sep-Pak (silica gel) cartridges was developed and found to be applicable for the analysis of some real samples. Several spiked and real samples were analysed by this method, with excellent sensitivity and precision.