Abstract

COMPUTER-AIDED DESIGN OF DIPHENYLETHERS AS EFFECTIVE ANTI – MYCOBACTERIUM TUBERCULOSIS

Abdulrahim A. Alzain*, Talal A. Awad and Mai A. Ali

Abstract

Tuberculosis (TB) is the second cause of death from an infectious disease in adults worldwide. However many antimycobacterials have been discovered up to date, but their success is hampered by Mycobacterium tuberculosis resistance. Computer-aided drug design is considered as one of the most efficient approaches that accelerate the process of drug discovery. Therefore, the aim of this in silico study is to evaluate antimycobacterial activity of diphenylether derivatives using computer aided drug design tools (Tripos Sybyl-X, and MOE packages). Enoyl Acyl carrier protein reductase enzyme (InhA) was selected as drug target, because of its vital role in type II fatty acid biosynthesis. 3D crystal structure of InhA (PDB 2X23) was obtained from protein data bank and prepared for docking. Twenty three diphenylether derivatives and known InhA inhibitor, PT70, were docked into the active site of the InhA enzyme. The obtained data (scores) were converted to free binding energy using special equation. The visualization within the active site showed the hydrogen bonding, π–π and van der Waals' interaction interactions between the enzyme and the tested ligands. The results of this study revealed that, among the docked compounds, compounds a1 and a19 were exhibited the lowest binding energies (high affinities) with values of -17.85 kcal/mol and-17.00 kcal/mole respectively, whereas the known inhibitor, PT70, showed-16.33 kcal/mol. It is observed that the length of the side chain R1 attached to ring A and type of side chain R2 and R3 attached to ring B played a vital role on the activity of the compounds. Further in vitro studies await to be conducted in order to corroborate antimycobacterials activity of diphenylether derivatives.

Keywords: Computer-Aided Design, in silico, Diphenylethers, InhA, Tuberculosis, Mycobacterium Tuberculosis.