Abstract
The carcinogenicity of commercial safflower yellow was examined in Fischer 344 rats of both sexes. Commercial safflower yellow was mixed in basal diet at levels of 0, 2.5 or 5.0%, and groups of 50 male and 50 female rats were administered each of these diets ad libitum. for 108wk. At final sacrifice no statistically significant differences between treated and control rats regarding mean body weight, or mortality, which was very low, were observed in either male or female. Many tumors developed in all groups including the controls and the organ distribution of neoplasms and their histological characterisitics did not differ significantly from those reported to occur spontaneously in this strain of rats. With the exception of C-cell adenomas of the thyroid gland which were increased in males receiving the 5.0% dose, no significant compound-related increases in tumor incidence over the corresponding control group were observed. Furthermore, such C-cell adenomas of the thyroid gland are frequent spontaneous tumors in F344 rats and the observed level was within the reported treatment-independent range. Moreover, no equivalent trend could be distinguished in the females. From these findings, it is concluded that commercial safflower yellow dose not induce tumors in F344 rats, when administered orally at doses of up to 5.0% mixed in basal diet for as long as 108wk.
