Original Articles
Radhakrishnan Narayanaswamy, L
Abstract
Quinone and its derivatives are well known to have various biological properties such as antineoplastic, antimalarial, antitumor, anticoagulant, herbicidal and antibiotic activities. They are also known to have inducible nitric oxide synthase (iNOS) inhibition activity. This prompted the present study to be carried out on 17 selected quinones which are menadione, thymoquinone, benzoquinone, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, 2,6-dimethyl-1,4-benzoquinone, 2,5-dimethyl-1,4-benzoquinone, duroquinone, hydroquinone, anthraquinone, 2-chloro-1,4-benzoquinone, 2-phenyl-1,4-benzoquinone, 2,3,5,6-tetrachloro-1,4-benzoquinone, 1,4-naphthoquinone, coenzyme Q10, triptoquinone A, idebenone and dopaquinone. These quinones were evaluated on their docking behaviour on inducible nitric oxide synthase (iNOS) using Discovery Studio Version 3.1. In addition, molecular physicochemical, drug-likeness, ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) and TOPKAT (Toxicity Prediction by Komputer Assisted Technology) analyses were done. The molecular physicochemical analysis revealed that all the tested ligands complied with Lipinski’s rule of five. ADMET analysis showed that all the ligands except coenzyme Q10 exhibited good intestinal absorption property. Docking studies and binding free energy calculations exhibited that coenzyme Q10 gave the highest interaction energy (-71.05 kcal/mol) and benzoquinone in contrast showed the least interaction energy (-14.84 kcal/mol). Hence, the results of this present study exhibited the potential of these quinones as inducible nitric oxide synthase (iNOS) inhibitory agents.