Inhibitory effects of phenolic compounds on benzo(a)pyrene-induced neoplasia.

Abstract

The inhibitory effects of 18 synthetic phenolic compounds added to the diet on benzo(a)pyrene-induced neoplasia of the forestomach of female ICR/Ha mice have been determined. Seven of the compounds showed suppression of neoplasia. The most potent inhibitors were p-methoxyphenol, 2-tert-butyl-4-hydroxyanisole [the minor isomer of 2(3)-tert-butyl-4-hydroxyanisole] and 3,5-di-tert-butylcatechol. A second group of compounds with a weaker inhibitory activity consisted of 3,5-di-tert-butylphenol, 3-tert-butyl-4-hydroxyanisole [the major isomer of 2(3)-tert-butyl-4-hydroxyanisole], 2-tert-butylhydroquinone, and 2-tert-butylphenol. In additional experiments, three naturally occurring phenolic derivatives of cinnamic acid, i.e., o-hydroxycinnamic acid, 3,4-dihydroxycinnamic acid (caffeic acid), and 4-hydroxy-3-methyoxycinnamic acid (ferulic acid), were investigated. All three suppressed benzo(a)pyrene-induced neoplasia of the forestomach. Humans ingest a variety of phenols. Data as to the inhibitory capacities of members of this group of compounds are of importance for evaluating the role that they play in determining the reaction to exposure to chemical carcinogens.