A bioassay of benzoin for possible carcinogenicity was conducted by incorporating the test chemical in diets of F344 rats and B6C3F1 mice. Benzoin is used as a photopolymerization catalyst, chemical intermediate, and flavor ingredient.
Groups of 50 male rats were fed diets containing 125 or 250 ppm benzoin for 104 weeks, and similar groups of female rats received feed containing 250 or 500 ppm. Groups of 50 mice of each sex were fed diets containing 2,500 or 5,000 ppm, benzoin for 104 weeks. Groups of 50 untreated rats and mice of each sex were used as matched controls. Rats and mice of either sex probably could have tolerated higher doses. An increased incidence of lymphomas or leukemia occurred in dosed male rats, but the observed dose-related trend was not statistically significant.
Mean body weights and clinical signs of low-dose, high-dose, and control male and female rats and male mice were comparable throughout the study. After week 44, mean body weights of dosed female mice were slightly lower (10% or less) than those of the controls.
The incidences of lymphomas that occurred in male mice varied with each dose but were not statistically significant when compared with those of matched controls.
Lymphomas or leukemias occurred in low-dose female mice at an incidence that was significant when compared with the matched controls. However, because the incidence of lymphomas or leukemias in the high-dose female mice was not significant, the occurrence of these tumors was not clearly related to administration of the test compounds.
Under the conditions of this bioassay, benzoin was not carcinogenic for F344 rats or B6C3F1 mice.