Phenozan, a Synthetic Phenolic Antioxidant, Inhibits the Development of Spontaneous Tumors in Rats and Mice

Synthetic phenolic antioxidant β-(4-hydroxy-3,5-di-tert-butylphenyl) propionic acid, named phenozan, is a potential antiepileptic drug. In pre-clinical trials this substance did not manifest any toxicity, and also inhibited the development of some spontaneous tumors in animals. The purpose of this study was to evaluate inhibiting effect of phenozan on spontaneous carcinogenesis in rats and mice. In experiments with rats LIO and mice SHR of local breeding, with high spontaneous tumor incidence, phenozan was dissolved in sunflower oil and administered by gavage in therapeutic dose 5 mg/kg 3 times per week for 18 months. There were no any signs of toxicity and differences in weight of animals during the phenozan treatment compared with the control (sunflower oil). Phenozan significantly reduced the overall incidence and multiplicity of all tumors but only multiplicity of malignant tumors, compared with the control. Moreover a significant decrease of overall incidence and multiplicity was observed in pituitary and breast tumors in females and only overall multiplicity of tumors of pituitary and lymphoid tissue in males. In mice phenozan reduced overall incidence and multiplicity of lung tumors (in females) and also overall multiplicity of all tumors (in females) and only malignant tumors (in males). These findings allow us to classify phenozan as anticarcinogenic agent. Anticarcinogenic activity of phenozan is important because clinical study of this drug as the possible antiepileptic drug goes along and it is known that such drugs are designed for long-term use.