The phytoestrogens coumoestrol and genistein induce structural chromosomalaberrations in cultured human peripheral blood lymphocytes

The clastogenic potential of the phytoestrogens coumoestrol (COUM), geniste in (GEN) and daidzein (DAI) has been studied in human peripheral blood lymp hocytes in vitro. After exposure of the cultured lymphocytes to 50 or 75 mu M COUM or 25 mu M GEN for 6 h, a clear induction of structural chromosomal aberrations was observed by cytogenetic analysis. The major alterations we re chromatid breaks, gaps and interchanges. In contrast, DAI did not induce chromosome aberrations even at 100 mu M. These results, together with prev iously published reports on the induction of micronuclei and DNA strand bre aks in cultured Chinese hamster V79 cells by COUM and GEN, but not DAI, sug gest that some but not all phytoestrogens have the potential for genetic to xicity.