Cytotoxic effects of the dietary flavones chrysin and apigenin in a normal trout liver cell line

Many flavonoids have been shown to possess prooxidant properties, capable of causing oxidative stress, especially at larger doses. Here, we examined the potential cell toxicity caused by exposure to the hydroxylated flavones chrysin, apigenin, luteolin and quercetin in comparison to the methylated flavones 5,7-dimethoxyflavone and 3′,4′-dimethoxyflavone in normal Rainbow trout hepatocytes. The hydroxylated flavones, especially chrysin, demonstrated cell toxicity and inhibition of DNA synthesis at very low (2 μM) concentrations. The cytotoxicity of chrysin may partially be due to its metabolism by myeloperoxidase, which was shown to be present in these normal trout liver cells (164 pmol/(min mg protein)). In contrast, methylated flavones showed no significant metabolism by myeloperoxidase and no signs of toxicity, even at much higher concentrations. These results may be useful for further investigations of cytotoxicity of dietary flavonoids.