Synthesis and evaluation of sulfonyl-substituted ruthenium complex as potential antibacterial activity against Staphylococcus aureus

Abstract

Anti-Staphylococcus aureus infection has become an increasingly common problem, especially since the emergence of some multi-drug resistant S. aureus, making bacterial infections difficult to cure. The purpose of this study was to develop a good antibacterial drug against S. aureus, which did not easily produce resistance in S. aureus. Therefore, we introduced new benzenesulfonyl groups and ruthenium dichloride compounds on the basis of the original research to synthesize a variety of metal ruthenium polypyridyl complexes. Firstly, the minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) tested for these ruthenium complexes against S. aureus. The MIC of the optimal compound Ru(II)-2 was 6.25 μg mL⁻¹. Then, the optimal ruthenium complex Ru(II)-2 could inhibit the formation of S. aureus biofilm at sub-inhibitory concentrations. In addition, in order to evaluate whether the complex can develop S. aureus resistance, a 20-generation drug-resistant induction experiment was performed, which showed that Ru(II)-2 had no change in the MIC values. Finally, we also evaluated the antibacterial effect of ruthenium complexes in mice infection model experiments to test the toxic and side effects of synthetic ruthenium complexes on normal cells. In addition, we found that our newly-synthesized ruthenium complex Ru(II)-2 has good antibacterial activity in vivo and in vitro, and exhibits lower cytotoxicity, which provides a certain basis for future research on anti-S. aureus to explore the inhibitory effect of S. aureus.