[QSAR analysis of the toxicity of a series of pyridines related to the mushroom toxin orellanine: comparison of the results obtained with physico-chemical, steric and quantal parameters].

To complete a preceding work, we have made a QSAR study of a series of mono- or bi-pyridines, aminoxidized or not, wearing diverse substituents and related to the mushroom toxin orellanine. For the description of these molecules, we tried several sterical parameters which we have recently defined (sigma D and sigma S) or which we define here (D3) as well as physical and quantal parameters calculated with the CNDO/2 method, besides the parameter of hydrophobicity log P. Among the regression equations obtained, three have a correlation coefficient greater than 0.96, which is very high, taking into account the nature of the biological response (LD50). The importance of the hydrophobicity and of the size of the molecules in the expression of their toxicity is confirmed, as well as the particularity of orellanine in the series studied.