Abstract
A wide variety of dietary supplements are available for the treatment of post-menopausal symptoms in women. Many women choose these supplements to avoid the potential unwanted side effects and long-term complications associated with traditional hormone therapy. In this study, we evaluated the in vitro estrogen activity of extracts from eleven supplements targeted for post-menopausal women to test the hypothesis that some of these supplements will induce estrogen activity in human breast cancer cell bioassays. Ethanol extracts (1 g: 1 mL) were prepared from the supplements: Amberen, Nature's Bounty Black Cohosh, Nature's Bounty St. John's Wort, Swanson Chasteberry Fruit, Nature's Way Red Clover, Promensil Real Health, Estroven, Relizen, Remifemin, and Equelle. Black cohosh, St. John's Wort, Chasteberry fruit, and red clover are standalone products that are not sold under a brand name. Promensil, Estroven, and Equelle contain isoflavones that have been reported to be estrogenic. Estroven and Remifemin contain black cohosh. Relizen contains a purified Swedish flower pollen extract and Amberen contains succinates, amino acids, minerals, and vitamin E. The estrogen activity of each extract was measured using both the T47D-kb-Luc estrogen responsive reporter gene and MCF-7 E3 proliferation estrogen bio-assays. The extracts from Nature's Way Red Clover, Promensil Real Health, and Equelle induced full estrogen agonist efficacy in the MCF-7 proliferation assay and more than full efficacy in the T47D-kb-Luc assay compared to estradiol. The agonist activity of these extracts in both bio-assays was inhibited by fulvestrant. Extracts from Nature's Bounty Black Cohosh, Nature's Bounty St. John's Wort, Swanson Chasteberry Fruit and Relizen induced less than full agonist estrogen activity only in the MCF-7 proliferation assay that was not, or not completely inhibited by fulvestrant. Thus, some supplements in this study likely target the estrogen receptor as agonists while others may be only weak estrogens that may also activate other proliferative pathways. While estrogen therapy is known to provide relief of some post-menopausal symptoms, estrogen use is associated with increased breast cancer risk. Consumers may benefit from information about the estrogen activity of supplements targeted for post-menopausal women. The results of this study may allow women to make more informed decisions about the use of these supplements. This study may be a prototype for evaluating the estrogen activity of dietary supplements for the purpose of informing consumers. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.