Hormonal activities of new brominated flame retardants

After the phase-out of two commercial mixtures of brominated flame retardants, an increasing number of alternative flame retardants have been introduced in commercial applications. None of them, however, has been thoroughly tested for its hormonal activity. We used two yeast reporter-gene assays to determine the potential of eleven compounds to interfere with estrogenic and androgenic pathways. Our data demonstrate the ability of 2,4,6-tribromophenol to lower the transcriptional activity of human estrogen and androgen receptors. A nominal IC50 value of 14.1 μM for anti-estrogenic and 3.9 μM for anti-androgenic activity was obtained using the luciferase reporter. An IC50 value of 9.2 μM was calculated for the anti-estrogenic activity measured by the β-galactosidase assay. Of the tested chemicals, this study highlights the endocrine disrupting effects of 2,4,6-tribromophenol whose occurrence in the environment should be monitored.

► 2,4,6-Tribromophenol antagonist effects on estrogen and androgen receptors were found.
► Two reporter-gene screens were employed to calculate EC50 of TBP.
► Anti-estrogenic activity of 1,2-bis(2,4,6-tribromophenoxy)ethane was observed.
► Anti-androgenic activity of pentabromobenzyl acrylate was detected.