Evaluation of Antibiofilm and Antimicrobial Activities of N-heterocyclic Carbene Complexes

In recent years, resistance to antimicrobials has become a global problem. Despite the need for new antibiotics with the increase of resistant bacteria, developing new antimicrobials is problematic. Biofilms formed by microorganisms play an essential role in the development of resistance. We aimed to investigate the antimicrobial and antibiofilm activities of N-heterocyclic carbene (NHC) complexes. In this study, previously synthesized and characterized NHC complexes on standard bacterial and fungal strains were investigated. The minimal inhibition concentration (MIC) test was used to determine the antimicrobial activities of the compounds, and the biofilm inhibition concentration test was used to determine the anti-biofilm activities. Compounds 2b and 2c showed potent antimicrobial activity on microorganisms between <=1.9 and 7.8µg/mL. Antimicrobial activity in salts of compounds (1a-1c) was weaker than silver compounds (2a-2c). The antibiofilm activity was between 27 and 79%, especially in silver-bound compounds (2a-2c). Benzimidazole derivative NHC compounds that we evaluated in our study were found to have significant antimicrobial and antibiofilm effects on pathogenic microorganisms. These compounds, which we assessed in our study, may be antimicrobial drug candidates that can be used in different areas. It will be essential to conduct further in vitro and in vivo studies on this subject.