On the other hand, the effects of RES over 3H-thymidine incorporation were not in linear correlation with the effects over cell number, indicating that it is probably acting on more than one biochemical event. Its IC50 for 3H-thymidine incorporation decrease, at 24 hours treatment, was found to be 71.2 _M.

EGCG showed an inhibitory effect upon cell growth, but was less potent than XN and RES. Only at the highest concentration tested, 100 _M, the proliferative inhibitory effect was statistically significant after 24 hours of treatment. At 50 _M, the inhibitory effect was significant only after 72 hours exposure. On the other hand, EGCG showed no cytotoxicity.

Conclusions The researchers concluded the following:

three polyphenolic compounds, EGCG, XN and RES, known to be abundant in tea, beer and red wine, respectively, when present in the nutritive medium of a breast cancer cell line (MCF-7), were all able to reduce cell proliferation. These effects could be observed at concentrations that were not cytotoxic. a decrease in 3H-thymidine incorporation, a commonly used index of DNA synthesis, was also observed in the presence of the compounds, very much in correspondence with the anti-proliferative effect in the case of XN. EGCG, in this selection of polyphenols, was the least potent on a weight basis, although that may have no therapeutic meaning since it was also the least toxic compound (i.e. it can be given in higher doses). these biochemical results, over breast cancer cells, add support and meaning to epidemiological studies that relate consumption of certain beverages with a lesser incidence and prevalence of cancer.

CaveatThis study does not call for women to increase alcohol consumption as a means of breast cancer prevention. The authors state that their findings suggest that further studies, namely in vivo studies, are necessary to fully support the inclusion of these compounds and/or beverages in diet recommendations in the perspective of cancer prevention.

The American Physiological Society (APS) is America ™s oldest biomedical sciences research society. The not-for-profit society, with some 11,000 members, is the publisher of 14 scientific journals, including the American Journal of Physiology, which has been published since 1898.