Exploring the antimicrobial potential of new selenium- N-heterocyclic carbene complexes and their benzimidazolium salts: synthesis, characterization, biological evaluation, and docking insights

Abstract

The present work, describes the synthesis and antimicrobial evaluation of new selenium-NHC adducts (3a-e) and their corresponding benzimidazolium salts (2a-e). Specific synthetic approaches were employed, resulting in compounds with satisfactory stability under humid and aerated conditions. Characterization by spectroscopic methods confirmed structural changes upon selenium incorporation. Biological evaluations revealed varying antimicrobial and antifungal activities among the synthesized compounds. The results indicated that the benzimidazolium salts exhibited significantly enhanced antimicrobial and antifungal activities compared to reference agents. For instance, compound 2a demonstrated an IC₅₀ value of 6.25 µg/mL against Candida albicans, which was comparable to the reference Caspofungin (6.25 µg/mL). Similarly, compound 2e demonstrated strong antibacterial activity against Staphylococcus aureus, with an IC₅₀ value of 0.8 µg/mL, significantly outperforming the reference Ampicillin (1.56 µg/mL). In contrast, the selenium-NHC adducts exhibited moderate to minimal activity, with compound 3e showing the highest IC₅₀ value of 25 µg/mL against Staphylococcus aureus, but failing to surpass the activity of the reference agent. To explore the potential mechanism of action, molecular docking studies were conducted against Escherichia coli DNA gyrase and CYP51. The molecular docking results demonstrate that synthesized compounds exhibit significant binding affinity against both enzymes, indicating antibacterial and antifungal potential. These binding affinities suggest that these molecules could be effective dual-action antimicrobial agents.

Graphical abstract