Antibacterial Activity of the Halogen- and Nitro Derivatives of Benzimidazole Against Bacillus Subtilis

Background. Antibiotic resistance of bacteria is a serious concern for modern medicine. The search for new compounds with a pronounced antibacterial effect is an urgent task of pharmaceutical chemistry. The aim of the study was to assess nfluence of the structure of benzimidazole and its derivatives the ability to inhibit the growth of gram-positive bacteria Bacillus subtilis. Materials and methods. Antibacterial activity of diazaheterocycles was evaluated by the method of serial dilutions. Сoncentrations from 0,06 to 1000 µg/l were used. Тhe minimum inhibitory concentration (MIC) of benzimidazole derivatives against Bacillus subtilis BKM B-407 was determined. The antibacterial effect of the studied halogen- and nitrobenzimidazoles was compared with the antimicrobial activity of benzimidazole. Results. The antimicrobial activity of the 12 benzimidazole derivatives was established. 2-trifluoromethylbenzimidazoles containing halogen atoms in the phenylene fragment had the most pronounced inhibitory effect. The dihalogenated derivatives exhibited greater antibacterial activity than the compounds with one halogen atom in the benzene ring. 5,6-dibromo-2-(trifluoromethyl)benzimidazole was the most active compound with an MIC of 0.49 µg/mL, comparable to the commercial antibiotic tetracycline. The antibacterial activity of erythromycin is a half that of this substance. Conclusions. Polyhalogen derivatives of benzimidazole are promising compounds for the development of new antimicrobial drugs against Gram-positive bacteria.