Regulation of human estrogen receptor by phytoestrogens in yeast and humancells

Phytoestrogens are defined as plant substances that are structurally or fun ctionally similar to estrogen. They are present in many foods and their hig her consumption in certain populations has been correlated with protection against many diseases including coronary heart disease, breast cancer and e ndometrial and ovarian cancer. In this report, ten phytoestrogens with dive rse chemical structures were studied for their binding to the human estroge n receptor and their transcription activation properties in yeast and mamma lian cells. Our results showed that some of these compounds bind with relat ively high affinity to the estrogen receptor and activate the receptor in t he yeast and mammalian cell system. In addition, none of these compounds sh owed anti-estrogenic activity. We conclude that the yeast system accurately predicts the estrogenic activity of compounds with diverse chemical struct ures in mammalian cells. In addition, our data with phytoestrogens that do not show transcription activation properties raise the possibility that the se compounds may exert their biological effects through pathways different from the classical estrogen signalling mechanism. (C) 1999 Elsevier Science Ltd. All rights reserved.