Reduced density gradient as a novel approachfor estimating QSAR descriptors, and its application to 1,4-dihydropyridine derivatives with potential antihypertensiveeffects

The relationship between the chemical structureand biological activity (log IC50) of 40 derivatives of 1,4-dihydropyridines (DHPs) was studied using density functionaltheory (DFT) and multiple linear regression analysis methods.With the aim of improving the quantitative structure-activityrelationship (QSAR) model, the reduced density gradient s(r)of the optimized equilibrium geometries was used as a descriptorto include weak non-covalent interactions. TheQSAR model highlights the correlation between the log IC50with highest molecular orbital energy (EHOMO), molecularvolume (V), partition coefficient (log P), non-covalent interactionsNCI(H4-G) and the dual descriptor [?f(r)]. The modelyielded values of R2=79.57 and Q2=69.67 that were validatedwith the next four internal analytical validations DK=0.076,DQ=?0.006, RP=0.056, and RN=0.000, and the external validationQ2boot=64.26. The QSAR model found can be used toestimate biological activity with high reliability in new compoundsbased on a DHP series.