QSAR Study on Antibacterial Effects of Benzimidazole and Imidazopyridine Derivatives

Abstract

A set of benzimidazole (I) and imidazopyridine (II) derivatives previously tested for their antibacterial activities against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Bacillus subtilis (B. subtilis) were analyzed by quantitative structure-activity relationship (QSAR) and the activity contributions for structural and substituent effects were determined using multiple regression procedure. The resulting QSAR revealed that for the activity contribution against S. aureus and P. aeruginosa the substituents of p-position on the phenyl moiety play important role, and besides the p-substituents the substituents in other positions improve the activity. For the potency against E. coli, the character of six membered ring of the fused ring system becomes important besides the substituents effects at the p-position of the phenyl group. It was also found that both the benzimidazole ring system and p-substituted benzyl moiety have significant structural effects besides the lipophilicity of the substituents at R3 for the activity against B. subtilis.