Antibiofilm and Antimicrobial Properties of 1-allyl-3-(2-diisopropylaminoethyl) Benzimidazolium Chloride and its Silver(I)-NHC Complex

Abstract

Today, the number of antimicrobials used in treatment has decreased, especially due to drug resistance. We need new antimicrobials. Biofilms are an important cause of antimicrobial resistance. In this study, the antimicrobial and antibiofilm properties of the salt and silver complex of benzimidazolium-based NHC compound, which were previously synthesized and characterized, were evaluated. The antimicrobial properties were tested using the broth microdilution method, while their antibiofilm potential was determined by microtiter plate assay. Salt of the NHC compound (1a) showed antimicrobial activity on microorganisms at concentrations between 31.25-125 µg/mL. The silver complex (2a) of the NHC compound showed higher antimicrobial and antibiofilm activity than the salt compound. This activity was highest on Candida albicans yeast (MIC 3.9 µg/mL). Compound 2a reduced the biofilm structure of C. albicans yeast by 86.1% compared to the control. In addition, compound 2a showed 76.4-80.6% antibiofilm activity on gram-negative bacteria. NHC compounds are seen as a promising resource for the development of new generation antimicrobials. The NHC compound evaluated in this study was found to have significant antimicrobial and antibiofilm activity. These compounds could be an important resource for the discovery of future biofilm-acting antimicrobials.