Synthesis and Antibacterial Action of New Ni(II), Pd(II) and Pt(II) Complexes with Benzimidazole-Derived Schiff Base Ligands

For decades, antimicrobial resistance has posed a growing threat to the effective treatment of an expanding range of infections caused by bacteria, parasites, viruses, and fungi. This issue disproportionately affects developing countries or those grappling with significant social inequality. In response, medicinal chemistry has developed various drugs that are effective in many cases. However, the improper use of these drugs and the adaptive strategies of prokaryotic cells to evade therapeutic agents have significantly diminished their pharmacological efficacy. To address this challenge, the development of new drugs is essential to improve treatment outcomes in a more efficient, less toxic manner and to overcome the phenomenon of resistance. This research focuses on the synthesis and antibacterial evaluation of novel Schiff base-type compounds derived from benzimidazoles coordinated with group 10 metals (nickel, palladium, platinum), which are well-documented for their antimicrobial and antitumor activities. The synthesized compounds were characterized using spectroscopic and spectrometric techniques, and their antibacterial activity was assessed in vitro against resistant bacteria isolated from the Magdalena region of Colombia, employing the broth microdilution method. The minimum inhibitory concentration (MIC) values ​​ranged between 250-0.5 μg/mL against resistant strains of gram-positive (S. aureus) and gram-negative (E. coli, K. pneumoniae) bacteria. Results indicate a synergistic effect between the metal center and the organic ligand, enhancing the biological activity. Notably, platinum-based complexes emerged as promising candidates , even presenting MIC up to 0.5 μg/mL, similar to ciprofloxacin used as a control drug for S. aureus.