Toxicity and tumorigenicity of purpurin, a natural hydroxanthraquinone in rats: induction of bladder neoplasms.

Chronic toxicity and tumorigenicity of purpurin, a natural hydroxyanthraquinone, was examined in two groups of male F344 rats. One group was given a basal diet mixed with purpurin at a concentration of 1% throughout the experiment (520 days). Another group was kept on the basal diet without purpurin during the experiment. Almost all animals given purpurin developed conspicuous changes of kidney resembling 'progressive chronic nephropathies', the severity and frequency of which were much stronger than in controls. In rats with purpurin treatment, marked hyperplasia of pelvic epithelium was frequently seen and several rats developed urinary bladder tumors (papilloma and carcinoma). Prominent crystallization in the renal pelvis and urinary bladder seems to be initially related to the toxic effects of this hydroxanthraquinone on the renal tubules and with the occurrence of epithelial hyperplasia and neoplasms.