Toxicity of hymenoxon in Swiss white mice following pretreatment with microsomal enzyme inducers, inhibitors and carbon tetrachloride.

Pretreatment of mice with the microsomal enzyme inducers, phenobarbital or polychlorinated biphenyl, or microsomal enzyme inhibitor, chloramphenicol, did not significantly alter the toxicity of hymenoxon. Pretreatment of mice with the hepatotoxin, carbon tetrachloride, provided significant protection against challenge dosages of hymenoxon. The LD50 of hymenoxon following carbon tetrachloride pretreatment was increased to 630 +/- 20.5 mg/kg as compared to the known oral LD50 of 241 +/- 10 mg/kg. These results suggest that a metabolite of hymenoxon may be responsible for the toxicity of this sesquiterpene lactone.