Synthesis and antimicrobial evaluation of novel 8-hydroxyquinoline containing benzimidazole hybrids

In the present study a series new 8-hydroxyquinoline-Benzimidazole hybrids (6a–l) were designed, synthesized (6a–l) by using conventional synthetic methods and assayed for their antimicrobial evaluation. The newly synthesized compounds (6a–l) were screened for their antibacterial activity against four strains i.e., E. coli, S. aureus, P. aeruginosa and B. subtilis and antifungal activity tested against A. niger and C. albicans. The compounds 6b, 6c, 6g, 6h, 6i, 6k and 6l are found to be active against all 4 bacterial strains. The compounds 6a, 6b, 6c, 6g, 6h, 6i, 6k and 6l are showing almost same antifungal activity when compared to the standard drug Voriconazole against A. niger. Whereas, In the case of C. albicans the compounds 6c, 6g, 6h, 6i, 6j, 6k and 6l are showing good antifungal activity. The MIC studies revealed that these compounds were showing the MIC values between 3.9 and 62.5 μg/ml for all the four bacterial strains. Among all the compounds, the compound 6g was showing the 3.9 μg/ml MIC value for E. coli and P. aeruginosa and found to be most potent compound antibacterial agent. From the results of the MIC studies exhibit that these compounds were good antifungal agents and showing the MIC values ranging between 19.2 and 500 μg/ml for both A. niger and C. albicans. The compound 6f was emerged as most potent antifungal agent by exhibiting the 22.3 μg/ml MIC value for A. niger and 19.2 μg/ml MIC value for C. albicans. Thus it is anticipated that these compounds will emerged as potential antibacterial as well antifungal agents on further exploration.