Molecular Descriptors for Quantitative Structure-Toxicity Relationship (QSTR) H. Three Ovality Molecular Descriptors and Their Use in Modeling the Toxicity of Aliphatic Alcohols on Tetrahymena pyriformis

摘要

The molecular descriptors reported in this paper, Θ_(iD), i=1,2,3 were constructed on the basis of the molecular uan der Waals (vdW) space, considered homogeneous, isotropic, and compressible in some extent. They were calculated as the ratios of the radii Θ_(1D)), surfaces ( Θ_(2D)), and volumes ( Θ_(3D)) of the greatest molecular sphere, corresponding to the udW surface area of a molecule, and those of the smallest molecular sphere, corresponding to the vdW volume of the same molecule. Ovality measures of the vdW molecular shape, Θ_Df were tested with good results (r>0.980, r_(adj)~2>0.960, q_(LOO)~2> 0.950) on a series of 35 aliphatic alcohols exhibiting toxicity to Tetrahymena pyriformis, measured as A-tog(l/IGC J, where IGC_(50) is the concentration which inhibits a 50% growth. The predictive ability of the QSTR models was estimated also by bootstrapping and LHO statistical procedures. The best model was obtained for the Θ_(3D)predictor variable:r>0.986, r_(adj)~2>0.971, q_(LOO)~2 > 0.968. The ovality molecular descriptors Θ_(id),i=1,2,3 can be easily calculated for any moleculenowever complex the structure is. They are good measures of the shape feature of toxicant molecule.