Preferential Synthesis and Pharmacological Evaluation of Mono- and Di-substituted Benzimidazole Derivatives

A series of substituted benzimidazoles were synthesized by condensing o-phenylenediamine with aromatic aldehydes in water using surfactants as catalyst. Mono and disubstituted benzimidazoles were formed preferentially with benzalkonium chloride and sodium dodecyl sulfate respectively. In silico molecular docking study revealed that 1-(4-chlorobenzyl)-2-(4-chlorophenyl)-1H-benzo[d]imidazole bound strongly with delta, mu and kappa opioid receptors with binding scores of -9.4, -8.7 and -9.9 Kcal/mol respectively. This derivative also possessed highest binding (-9.0 Kcal/mol) against tubulin (binding score of albendazole was -6.4 Kcal/mol). The molecule also showed potential antibacterial activity with MIC50 ranging 16-128 mu g/ml in in vitro antibacterial assay. Two benzimidazole derivatives showed powerful interaction with cyclooxygenase-1 and cyclooxygenase-2 (-8.1 and -8.9 Kcal/mol respectively) indicating their high analgesic and anti-inflammatory potentials. All the compounds produced significant binding (-5.2 to -8.2 Kcal/mol) towards urate oxidase, glutathione reductase and peroxiredoxin. Monosubstituted derivative 4-(1H-benzo[d]imidazol-2-yl)phenol displayed superior binding (-6.5 Kcal/mol) with glucosamine 6-phosphate synthase compared to ciprofloxacin (-6.3 Kcal/mol). In PASS analysis, monosubstituted derivatives demonstrated significant drug-like potential (Pa>0.7). Hence, the synthesized benzimidazole derivatives can be used as potential leads for developing new drugs.