New Pyrazolo-Benzimidazole Mannich Bases with Antimicrobial and Antibiofilm Activities.

A new series of pyrazolo-benzimidazole hybrid Mannich bases were synthesized, characterized by H-NMR, C-NMR, IR, UV-Vis, MS, and elemental analysis. In vitro cytotoxicity of the new compounds studied on fibroblast cells showed that the newly synthesized pyrazolo-benzimidazole hybrid derivatives were noncytotoxic until the concentration of 1 μM and two compounds presented a high degree of biocompatibility. The antibacterial and antibiofilm activity of the newly synthesized compounds was assayed on Gram-positive ATCC25923, ATCC29212, and Gram-negative ATCC27853, ATCC25922 strains. All synthesized compounds are more active against all three tested bacterial strains ATCC25923, ATCC29212, and ATCC25922 than reference drugs (Metronidazole, Nitrofurantoin), with the exception of compounds and , which are less active compared to Nitrofurantoin, and all synthesized compounds are more active against ATCC27853 compared to reference drugs (Metronidazole, Nitrofurantoin). Compound showed the best activity against ATCC 25923, with a MIC of 150 μg/mL and has also inhibited the biofilm formed by all the bacterial strains, having an MBIC of 310 µg/mL compared to the reference drugs (Metronidazole, Nitrofurantoin).