Toxicity studies on clove cigarette smoke and constituents of clove: determination of the LD50 of eugenol by intratracheal instillation in rats and hamsters.

Eugenol, eugenol acetate, beta-caryophyllene, and alpha-humulene are constituents of clove and clove cigarette smoke. The toxicity of these compounds was evaluated by intratracheal instillation in male F-344 rats. Eugenol was most toxic in this assay. The LD50 of eugenol was 11 mg/kg in male F-344 rats and 17 mg/kg in male Syrian golden hamsters. Congestion of the lung with interstitial hemorrhages, acute emphysema, and acute pulmonary edema were among the macroscopic and histologic findings observed in the animals after intratracheal administration of eugenol. Similar effects were not observed with male Syrian golden hamsters exposed to clove cigarette smoke. The estimated daily intake of eugenol for those hamsters exposed to clove cigarette smoke was below 2 mg/kg.