Estrogenic activity of herbs commonly used as remedies for menopausal symptoms

Objective: Women are increasingly turning to herbal therapies in an effort to manage their menopausal symptoms. In this study, we investigate the estrogenic activity of four selected herbs commonly used in menopause, namely dong quai, ginseng, black cohosh, and licorice root. Design: We investigated the effect of these selected herbs on cell proliferation of MCF-7 cells, a human breast cancer cell line. We also assessed their estrogenic activity in a transient gene expression assay system using HeLa cells co-transfected with an estrogen-dependent reporter plasmid in the presence of human estrogen receptor ERα or ERβ cDNA. Finally, we investigated the estrogenic activity of these herbs using a bioassay in mice. Results: Dong quai and ginseng both significantly induced the growth of MCF-7 cells by 16- and 27-fold, respectively, over that of untreated control cells, while black cohosh and licorice root did not. The herbs tested failed to show transactivation of either hERα or hERβ and had no effect on uterine weight in vivo when administered orally to mice for a period of 4 days. Conclusions: Our studies show that dong quai and ginseng stimulate the growth of MCF-7 cells independent of estrogenic activity. Because of the lack of efficacy and the potential for adverse effects, use of these herbs in humans warrants caution pending further study.