Bisphenol A is most commonly used in the production of polycarbonate plastic and epoxy resin. Its endocrine, carcinogenic, mutagenic effects and immunotoxic effects have already been established. It also increases the risk of developing certain diseases. Due to these facts, there was a need for bisphenol A substitutes, which would have similar functionality but fewer adverse effects on living organisms. We were interested in comparing their cytotoxic and immunomodulatory effects to bisphenol A, as well as the immunomodulatory properties of mixtures of bisphenol A with its substitutes.
We studied 16 bisphenol A substitutes: bisphenol AF, bisphenol AP, bisphenol B, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol P, bisphenol PH, bisphenol S-monoalyl ether, bisphenol S-monobenzyl ether, bisphenol Z, BTUM, pergafast 201, tetramethyl bisphenol F and 2,4-bisphenol S. The effects of these compounds on immune cells were evaluated on lymphoblastoid cell lines from three unrelated donors. These cell lines represent in vitro model for assessing the immunomodulatory properties of compounds.
First, we studied the cytotoxicity of the substitutes and found that six substitutes were less, while ten were more cytotoxic than bisphenol A. The most cytotoxic compounds had the lowest inhibitory concentration, 19,5 µM (bisphenol G), 28,6 µM (bisphenol P), and 30,6 µM (bisphenol PH). We determined that half-maximal inhibitory concentration correlates with logarithm of the partition coefficient, suggesting that higher cytotoxicity of more lipophilic compounds is likely related to better and easier membrane permeability.
We also studied effects of individual bisphenol A substitutes and binary mixtures of bisphenol A with five substitutes on the modulation of cytokine release. Binary mixtures had stronger impact on modulation of cytokine release than individual bisphenols at 10 µM concentration. The bisphenol A/bisphenol AP mixture stood out the most, significantly inhibiting the secretion of interleukine 2, 6, 10, and tumor necrosis factor alpha. In the last part, we found a non-monotonic effect of bisphenols on the Ramos-Blue cell line, 10 µM concentration decreased the activity of nuclear factor κB/activator protein 1, while 100 nM concentration increased it.
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