In vitro evaluation of novel Ru (II) complexes of thiazolhidrazinylidene-chroman-2,4-diones for their potential antibacterial activity

Numerous studies have demonstrated the ability of Ru complexes to inhibit the growth of various bacterial strains, including both Gram-positive and Gram-negative bacteria. A library of (η6-p-cymene)Ru (II) and Ru (II) bis-bpy bearing thiazolhidrazinylidene-chroman-2,4-dione was synthesized, characterized and all novel complexes were evaluated for their antibacterial activity, and cytotoxicity. From this library, many compounds were identified as being active, against Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA). A polypyridyl complex, 14, showed a remarkable minimum inhibitor concentration (MIC) of 3.12 µM and therapeutic index (T.I) of >32. We performed mechanism of action studies for several complexes. We could assign disruption of bacterial membrane integrity as a possible mode of action of piano stool arene species, while the mode of action of polypyridyl complexes remains elusive.