Long used in polycarbonate plastics, epoxy resin food-can liners, and thermal receipt paper, bisphenol A (BPA) has become a poster child for endocrine disruptorscompounds that mimic or interfere with the bodys hormones, such as oestrogens and androgens. Many manufacturers have replaced BPA with alternatives in recent years, but dozens of BPA substitutes lack data on their potential oestrogenic activity. Now, a new computer model provides a way to determine whether a BPA substitute shows high potential to bind the oestrogen receptor and requires further testing for its endocrine disrupting effects. Huixiao Hong of the Food & Drug Administrations National Centre for Toxicological Research and his colleagues developed a model that assesses how well a compound orients itself with the oestrogen receptor, and then estimates binding affinity by calculating how energetically favourable the binding is. The researchers trained the model by running it on 18 BPA substitutes that already have oestrogenic activity data and two reference compounds: BPA itself and 17?-estradiol, a key female sex hormone. When the researchers ran the model on 27 BPA substitutes that lacked experimental data on oestrogenic activity, the model identified 11 that met the criteria for binding to the receptor. Many compounds were predicted as better potential binders than BPA, including tetrabromobisphenol A, used in plastics and as a flame retardant, and bis-(3-allyl-4-hydroxyphenyl)sulfone, used in thermal receipt paper. Binding the receptor alone isnt sufficient to make the compound an endocrine disruptor, the researchers note. But they add that the findings do suggest the need for additional studies of these compounds safety.
Chemical & Engineering News, 16 September ;http://pubs.acs.org/cen/news ;