MON-033 Evaluating the Estrogen Activity of OTC Products Containing Parabens

Abstract

Parabens such as methylparaben, ethylparaben, and propylparaben are widely used in food products, cosmetics, and pharmaceuticals as preservatives. Many products contain multiple parabens to enhance the preservative effect. Parabens have been shown to be weak estrogens with alkyl chain length directly related to activity. In this study, we test the hypothesis that extracts of OTC products containing paraben preservatives will induce estrogen activity in human breast cancer cells in culture. Five frequently used OTC products were selected where equivalent pairs of products (same active ingredient) were available: one with and one without paraben preservatives in the formulation. Ethanol extracts and dilutions were prepared of OTC preparations of: Calcium Carbonate, Bisacodyl, Ibuprofen, Diphenhydramine and Benzoyl Peroxide (1 gm:1 ml). The estrogen agonist and antagonist activity of each extract was determined using the T47dkbluc estrogen reporter gene and the MCF-7 E3 estrogen responsive proliferation assays. Estrogen agonist activity was observed after treatment with extracts from Bisacodyl and Benzoyl Peroxide preparations. Formulations of Bisacodyl with and without parabens each induced similar estrogen agonist activity. The Bisacodyl structure suggests some features of the estrogen pharmacophore and estrogen activity has been reported in the literature. Thus, observed Bisacodyl extract estrogen effects are likely due to the active ingredient. Estrogen activity of Benzoyl Peroxide extracts was only observed in the extract deriving from the formulation that contained parabens and thus activity is likely due to the paraben preservative. While Ibuprofen and Diphenhydramine product extracts with or without parabens did not induce significant estrogen activity in the bioassays, extracts from these products induced estrogen activity when combined with the antiestrogen fulvestrant. The cause for this apparent initiation of estrogen activity from antiestrogen treatment is unknown. This study highlights the potential for paraben preservatives in OTC products to induce observable estrogen activity. The importance of determining the estrogen activity of OTC products in general is also illustrated. While the capacity for OTC preparations containing parabens (or other estrogenic substances) to induce estrogen activity in individuals using the products is unclear, consumers may interested in the presence of estrogenic components in commonly used OTC products.