The intake of selected minerals, especially zinc, calcium and selenium, and high consumption of dietary isoflavones are recognised as factors influencing prostate cancer risk. Moreover, changes in levels of some essential elements are characteristic of the disease. Here, we examined the combined effects of main dietary isoflavonoids (genistein, daidzein and its metabolite, equol) and minerals implicated in prostate cancer, namely zinc, selenium, copper, iron and calcium, on LNCaP prostate cancer cells proliferation. Secondly, we evaluated the influence of the combinations on genotoxicity of model mutagens, 4-nitroquinoline oxide (4NQO) and 2-aminoanthracene (2AA), in the umu test. All combinations of isoflavonoids and minerals inhibited prostate cancer cells growth. However, only mixtures with iron ions had significantly stronger effect than the phytochemicals. Interestingly, we observed that only genistein attenuated genotoxicity of 4NQO. The addition of any tested mineral abolished this effect. All tested isoflavonoids had anti-genotoxic activity against 2AA, which was significantly enhanced in the presence of copper sulphate. Our results indicate that the tested minerals in physiological concentrations had minimal influence on the anti-proliferative activity of isoflavonoids. However, they significantly modulated the anti-genotoxic effects of isoflavonoids against both metabolically activated and direct mutagens. Thus, the minerals intake and nutritional status may modulate protective action of isoflavonoids.
Keywords: anti-genotoxicity; calcium; chemoprevention; copper; iron; isoflavonoid; prostate cancer; selenate; zinc.