| Popis: |
Methylparaben, ethylparaben, and propylparaben are widely used as preservatives in food products, cosmetics, and pharmaceuticals. Parabens have been shown to be weak estrogens and this laboratory has described that extracts of some over the counter (OTC) medications with paraben preservatives can induce estrogen activity in tissue culture-based bioassays. At the same time, this laboratory determined that extracts from OTC medications containing the laxative bisacodyl induce estrogen activity regardless of parabens present and that bisacodyl is estrogenic. The current report describes the use of paraben standards and LC-MS analysis to determine paraben concentrations in extracts from OTC medications (Calcium Carbonate, Bisacodyl, Ibuprofen, Diphenhydramine, and Benzoyl Peroxide) used in previous studies. Also described is the application of the Qiagen RT2 Profiler PCR Array for Human Estrogen Receptor Signalling to determine gene induction profiles in MCF-7 cells treated with methyl, ethyl or proplyparaben, or each of the five pairs of OTC medication extracts (with or without parabens) relative to estradiol treatment. LC-MS analysis of extracts confirmed that five of six OTC medications labeled as paraben-free contain no detectable parabens, while one “paraben free” extract included measurable levels of parabens. At the same time, all of the extracts of OTC medications with paraben ingredients, some of which induce estrogen activity, were found to contain a wide range of paraben concentrations. A threshold range of paraben concentration in OTC medications is required to induce estrogen activity in bioassays. Analysis of paraben concentrations of extracts from different product lots of the same OTC medication identified discrepancies in the amount of paraben between batches. PCR Array profiles of the three paraben standards and the OTC medication extracts share some gene induction characteristics induced by estradiol. At the same time, methyl, ethyl and propylparabens induced unique gene array profiles that are shared by the OTC medication extracts containing parabens. The extracts of OTC medications containing bisacodyl stimulated a distinct gene induction profile that has some features of the profiles of estradiol and paraben treatment. This study highlights both the capacity for paraben preservatives in OTC medications to induce novel estrogen activity (gene induction) and the importance of determining the paraben concentration in OTC medications to determine estrogen potential. While the capacity for OTC medications containing parabens or other estrogenic substances to induce estrogen activity in individuals using the medications is unclear, consumers may want to know the potential for estrogen activity in these products. |
