Anti-HIV and antimicrobial activity in vitro of some new Benzimidazole derivatives

A series of 2-(1H-benzo[d]imiazol-1-yl)-N-4-aryl acetamides (11-20) were synthesized and evaluated to investigate their possible anti-HIV and antimicrobial activities. HIV-1 RT inhibitory activity was evaluated by using HIV-1 RT RNA-dependent DNA polymerase activity assay. Among these derivatives, compounds 12 and 20 were found to have reasonable HIV-1 RT inhibitory activity while the rest exhibited weak activity in comparison to the standard efavirenz. On the other hand, most of the test compounds were found to be significantly effective against gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and some gram-negative bacterial strains (E.coli, Salmonella typhi, Klebsiella pneumoniae and Pseudomonas aeruginosa), among which compounds 12, 13, 17 and 19 sprouted out as the most effective antibacterials but less effective than the standard ciprofloxacin. In case of fungal strains like Candida albicans and Aspergillus niger, almost all the compounds were found to exhibit potency comparable or more than that of standard drug fluconazole except for the compound 11 which exhibited moderate to good activity against both the fungal strains. For a deep insight into the role of different functional groups at different positions of phenyl ring attached with the help of a linker group to the N-1 position of benzimidazole, structure activity relationship (SAR) study was carried out, which clearly states the importance of chloro and methyl groups in enhancing the antimicrobial activity. ADME prediction study also indicates the significant drug like properties of the derivatives.