Response-surface analyses for toxicity to Tetrahymena pyriformis: reactive carbonyl-containing aliphatic chemicals.
A response-plane has been developed with Tetrahymena pyriformis population growth impairment toxicity data [log 1/50% growth inhibitory concentration (IGC50)], the 1-octanol/water partition coefficient (log Kow), and the energy of the lowest unoccupied molecular orbital (Elumo). A statistically robust plane [log 1/IGC50 = 0.530 (log Kow) -0.890 (Elumo) -0.271, n = 50, s = 0.295, r2 = 0.855, F = 145] was found for reactive carbonyl-containing aliphatic chemicals. These compounds had a variety of electrophilic mechanisms of action and included aldehydes acting as Schiff-base formers, alpha,beta-unsaturated aldehydes and alpha,beta-unsaturated ketones acting as Michael-type acceptors, and selected alpha-diones acting as selective binders to arganine residues; gamma-diones acting as selective binders to tubulin; and beta-diones with unknown mechanisms of action. Outliers to this model broadly fell into two groups: small reactive molecules (e.g., acrolein) that were more toxic than predicted and molecules in which the reactive center was sterically hindered by an alkyl group (e.g., 2,4-dimethyl-2,6-heptadienal) that were less toxic than predicted.
Schultz
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TW
College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071, USA.
Cronin
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MT
D000818:Animals; D003198:Computer Simulation; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry* / Q000633:toxicity*; D013329:Structure-Activity Relationship; D013769:Tetrahymena pyriformis / Q000187:drug effects* / Q000254:growth & development
D009930:Organic Chemicals