Synthesis, spectral characterization, biological activity, and soil:water fate of brominated 17ß-estradiol isomers

Authors: Hakk, Heldur; SVENDSEN, SKYLER - Concordia College; Shappell, Nancy; RUTHERFORD, DREW - Concordia College

Submitted to: American Chemical Society
Publication Type: Abstract Only
Publication Acceptance Date: 3/16/2015
Publication Date: 8/16/2015
Citation: Hakk, H., Svendsen, S.A., Shappell, N.W., Rutherford, D. 2015. Synthesis, spectral characterization, biological activity, and soil:water fate of brominated 17ß-estradiol isomers. American Chemical Society. p. 84.

Interpretive Summary: Estrogens are eliminated from nearly all animals in significant quantities, and when released into the environment they can act as endocrine disrupting compounds, particularly to aquatic organisms. Tracing the movement of estrogens from animal waste to impacted waters is complicated by historical estrogen deposits in soils, as well as their uncontrolled introduction by wildlife. Tracer studies can be conveniently performed with radiochemicals; however, these are not always suitable for field-scale research. Stable, brominated analogs of estrogens may prove a fruitful method to study the movement of theses endocrine disrupting compounds in the field. Therefore, the aim of this project was to synthesize brominated 17ß-estradiol analogs, to spectrally characterize the products formed, conduct bioassays evaluating the estrogenicity of synthetic products, and to utilize one of the isomers synthesized in a field-scale tracer study. Mild bromination of 17ß-estradiol was accomplished with molecular bromine, and various experimental conditions were tested to evaluate the effects on product yield and regioselectivity of bromination. Full characterization of products by 1H- and 13C-NMR, as well as electron impact-gas chromatography/mass spectrometry were completed. The biological activity of each brominated 17ß-estradiol isomer was evaluated in the E-Screen assay, measuring cell proliferation in response to exposure to estrogenic compounds in non-transfected MCF-7 BOS cells. The soil:water fate and transport of two of the monobrominated 17ß-estradiol isomers will be reported from laboratory batch sorption experiments using radiolabeled analogs relative to parent 17ß-estradiol. Bromination reactions were also applied to estrone, testosterone , androstendione, progesterone, cortisol, and cholesterol in order to elucidate the bromination reaction mechanism.

Technical Abstract: Estrogens are eliminated from nearly all animals in significant quantities, and when released into the environment they can act as endocrine disrupting compounds, particularly to aquatic organisms. Tracing the movement of estrogens from animal waste to impacted waters is complicated by historical estrogen deposits in soils, as well as their uncontrolled introduction by wildlife. Tracer studies can be conveniently performed with radiochemicals; however, these are not always suitable for field-scale research. Stable, brominated analogs of estrogens may prove a fruitful method to study the movement of theses endocrine disrupting compounds in the field. Therefore, the aim of this project was to synthesize brominated 17ß-estradiol analogs, to spectrally characterize the products formed, conduct bioassays evaluating the estrogenicity of synthetic products, and to utilize one of the isomers synthesized in a field-scale tracer study. Mild bromination of 17ß-estradiol was accomplished with molecular bromine, and various experimental conditions were tested to evaluate the effects on product yield and regioselectivity of bromination. Full characterization of products by 1H- and 13C-NMR, as well as electron impact-gas chromatography/mass spectrometry were completed. The biological activity of each brominated 17ß-estradiol isomer was evaluated in the E-Screen assay, measuring cell proliferation in response to exposure to estrogenic compounds in non-transfected MCF-7 BOS cells. The soil:water fate and transport of two of the monobrominated 17ß-estradiol isomers will be reported from laboratory batch sorption experiments using radiolabeled analogs relative to parent 17ß-estradiol. Bromination reactions were also applied to estrone, testosterone , androstendione, progesterone, cortisol, and cholesterol in order to elucidate the bromination reaction mechanism.