Rationalization of physico-chemical properties of 5, 6-diarylthiazolo [3,2-b]-1, 2, 4-triazoles towards cyclooxygenase-2 (COX-2) inhibition: A QSAR approach

Abstract

Quantitative structure-activity relationship (QSAR) analysis was performed on a series of 5, 6-diarylthiazolo [3, 2-b]-1, 2, 4-triazoles to explore their possible interaction with the active amino acid residues of cyclooxygenase-2 (COX-2) enzyme. The significance of orientation and conformational rigidity of 5, 6-diarylthiazolo [3, 2-b]-1, 2, 4-triazoles for COX-2 inhibition is discerned by the spatial descriptor principle moment of inertia-X component, PMI-X. The negative contribution of PMI-X indicates the necessity of orientation of substituents towards X-axis of aromatic ring for better activity. The most common electronic interaction between the title compounds and active residues of COX-2 enzyme is corroborated well by the positive contribution of molecular dipole. The contribution of molecular dipole suggests the non-covalent, electronic interactions between 5, 6-diarylthiazolo [3, 2-b]-1, 2, 4-triazoles and binding site of COX-2 enzyme. Our findings reveal the necessity of less bulkier, less polar substituents on the parent structure for better COX-2 inhibitory activity. The limited tolerance of COX-2 enzyme active site towards the bulk of interacting molecules is evident from the negative coefficient of calculated molar refractivity (CMR) in our models.