A quantitative structure-activity relationship (QSAR) study on a few series of potent, highly selective inhibitors of nitric oxide synthase.

QSAR study was performed on a series of 1,2-dihydro-4-quinazolinamines, 4,5-dialkylsubstituted-2-imino-1,3-thiazolidine derivatives and 4,5-disubstituted-1,3-oxazolidin-2-imine derivatives studied by Tinker et al. [J Med Chem (2003), 46, 913-916], Ueda et al. [Bioorg Med Chem (2004) 12, 4101-4116] and Ueda et al. [Bioorg Med Chem Lett (2004) 14, 313-316], respectively, as potent, highly selective inhibitors of inducible nitric oxide synthase (iNOS). The iNOS inhibition activity of the whole series of compounds was analyzed in relation to the physicochemical and molecular properties of the compounds. The QSAR analysis revealed that the inhibition potency of the compounds was controlled by a topological parameter 1v (Kier’s first order valence molecular connectivity index), density (D), surface tension (St) and length (steric parameter) of a substituent. This suggested that the drug-receptor interaction predominantly involved the dispersion interaction, but the bulky molecule would face steric problem because of which the molecule may not completely fit in active sites of the receptor and thus may not have the optimum interaction.

A QSAR and molecular modeling study on a series of 3, 4-dihydro-1-isoquinolinamines and thienopyridines acting as nitric oxide synthase inhibitors.

A quantitative structure-activity relationship (QSAR) and molecular modeling study were performed on a series of 3,4-dihyro-1-isoquinolinamines and thienopyridines reported by Beaton et al. [Beaton et al. (2001) Bioorg Med Chem Lett 11, 1023-1026, 1027-1030] as potent, highly selective inhibitors of two isoforms of nitric oxide synthase (NOS) — neuronal NOS (nNOS) and endothelial NOS (eNOS), in order to find the physicochemical properties that governed their activity and the mode of interaction with the receptors, so that still more potent compounds in the series could be suggested. A multiple regression analysis revealed that nNOS and eNOS inhibition potency of these compounds could be controlled by their hydrophobic property and molar refractivity, respectively. Thus, nNOS and eNOS inhibition was indicated to involve the hydrophobic interaction and steric effects, respectively, suggesting some structural differences of the two isoforms of NOS. Based on the correlations obtained, some new, more potent compounds belonging to the series were predicted. These compounds were then docked into the receptors to see their interactions and find out the docking scores. The docked structures of two representative compounds, whose interaction energies with nNOS and eNOS, respectively were found to be the lowest, were given as an example to exhibit the possible orientation of the compounds to interact with the receptors.