Ellagic acid toxicity and interaction with benzo[a]pyrene and benzo[a]pyrene 7,8-dihydrodiol in human bronchial epithelial cells.

Ellagic acid, a plant phenol present in various foods consumed by humans, has been reported to have both anti-mutagenic and anti-carcinogenic potential. To evaluate the potential anti-carcinogenic property of ellagic acid, we tested its effects on the toxicity of benzo[a]pyrene and benzo[a]pyrene, 7,8-dihydrodiol and binding of benzo[a]pyrene to DNA in cultured human bronchial epithelial cells. The toxicity of ellagic acid itself for human bronchial epithelial cells was also determined. Using a colony-forming efficiency assay, it was found that a nontoxic concentration of ellagic acid (5 micrograms/ml) enhanced the toxicity of benzo[a]pyrene 7,8-dihydrodiol in human bronchial epithelial cells. In contrast, ellagic acid at concentrations of 1.5 and 3.0 micrograms/ml inhibited binding of benzo[a]pyrene metabolites to DNA in these cells. An explanation for the potentiating effect of ellagic acid on the toxicity of benzo[a]pyrene, 7,8-dihydrodiol will require further investigation into the possible mechanisms of interaction between these two compounds.