The toxicity of macrocyclic trichothecenes administered directly into the rat brain.

The tested macrocyclic trichothecenes are produced by Myrothecium fungi and by the plant Baccharis megapotamica. The toxicity of five macrocyclic trichothecenes has been measured by intracerebral and subcutaneous injection into rats. It is assumed that the toxic effects are based on inhibition of protein synthesis. Intoxication of rats by these compounds finds expression in slowly progressing respiratory depression and paralysis of skeletal muscles. The macrocyclics are derived from verrucarol, which lacks ring D and exhibits only low toxicity. The high toxicity of the macrocyclics, established by intracerebral and subcutaneous applications, may thus be attributed to the presence of the large ring D.