Toxicological study of nitrobenzene derivatives against tetrahymena pyriformis using topological parameters.

P. N. Tripathi* and Vibhanjali

Abstract

Eight topological descriptors namely molar refractivity, solvent accessible surface area (SASA), shape index (order- 1), shape index (order-2), shape index (order-3), valence connectivity index (order-0), valence connectivity index (order-1) and valence connectivity index (order-2) of fifty four nitrobenzene derivatives have been calculated with the help of CAChe Pro of Fujitsu software. Observed toxicities of all compounds are in terms of -log (IGC50), mM, which is the inverse logarithm of the concentration causing 50% growth inhibition of Tetrahymena pyriformis after 40 hours. These eight descriptors have been used in developing QSTR models with the help of multi linear regression (MLR) analysis. The quality of regression has been adjudged by correlation coefficient, cross validation coefficient and statistical parameters like standard error, standard error of estimate, degrees of freedom etc. The QSTR model developed from descriptors molar refractivity, solvent accessible surface area, shape index (order-1) and valence connectivity index (order-2) have very high predictive power and can be used to find out the toxicity of any new derivative of nitrobenzene. Reliable QSTR model has been obtained from single descriptor shape index (order-1) which is also present in all best four QSTR models. Therefore, shape index (order-1) appears an important descriptor for the toxicological study of nitrobenzene derivatives.