QSARs for monosubstituted phenols and the polar narcosis mechanism of toxicity.
Eighty 2-, 3-, and 4-position monosubstituted phenols representing various substituents were evaluated for relative toxicity, log IGC50(-1), with a short-term static protocol in the Tetrahymena population growth inhibition bioassay. Quantitative structure-activity relationships (QSAR) were examined using the 1-octanol/water partition coefficient (log K(ow)) and ionization constant (pKa) as independent variables. Four derivatives did not elicit the measured response at saturation. Five derivatives revealed altered high-performance liquid chromatography spectra with time. None of these derivatives were included in QSAR development. In addition, the carboxyl and nitroso derivatives were detected as statistical outliers. The model log IGC50(-1) = 0.6655 (log K(ow)) - 0.1464 (pKa) + 0.2206, n = 67, r2 = 0.909, s = 0.212, was found to be an excellent predictor of activity of phenols which elicit their toxic response by the polar narcosis mode of action. For the most part the tested derivatives showed little abiotic loss over the duration of the bioassay.
College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071.
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Schultz
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Lin
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Wesley
D000818:Animals; D001681:Biological Assay; D015233:Models, Statistical; D010636:Phenols / Q000633:toxicity*; D012044:Regression Analysis; D015203:Reproducibility of Results; D013329:Structure-Activity Relationship; D013768:Tetrahymena
D010636:Phenols