STRUCTURE-TOXICITY RELATIONSHIPS FOR PHENOLS TO TETRAHYMENA-PYRIFORMIS

Quantitative structure-activity relationships are developed for the to xicity of 166 varied phenol derivatives to the ciliate Tetrahymena pyr iformis. A variety of physico-chemical descriptors were calculated but no significant relationship could be obtained for all 166 compounds. When certain chemical groups were omitted from the correlation however , notably the carboxyl-, amino-, nitro-, nitroso and acetamide- substi tuted phenols, an excellent correlation was obtained between toxicity and two parameters. These two parameters (log P and energy of the lowe st unoccupied molecular orbital) are explained mechanistically in that they model transport and electrophilicity. The resultant QSAR gave ac curate prediction of the toxicity of alkyl, halogenated, alkoxy and al dehyde substituted phenols. (C) 1996 Elsevier Science Ltd.