Antibacterial activity of naphthyl derived bis-(3-hydroxy-4-pyridinonate) copper(II) complexes against multidrug-resistant bacteria

• Published in: Journal of inorganic biochemistry 2019-08, Vol.197, p.110704-110704, Article 110704
• Main Authors: Leite, Andreia, Bessa, Lucinda J., Silva, Ana M.G., Gameiro, Paula, de Castro, Baltazar, Rangel, Maria
• Format: Article
• Language: English
• Subjects: 3-hydroxy-4-pyridinones; Antibacterial activity; Copper(II) complexes; Multidrug-resistant isolates; Synergy with ciprofloxacin
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2019.110704

In this work, we report the synthesis and characterization of three novel copper(II) complexes of naphthyl derived 3-hydroxy-4-pyridinone chelators. Their antibacterial activity against several Gram-positive and Gram-negative reference strains and multidrug-resistant clinical isolates was assessed through determination of the minimum inhibitory concentration (MIC). The complex Cu(naph1pp)2 shows the highest antibacterial activity, including against multidrug-resistant isolates, nonetheless, being more active against Gram-positive than Gram-negative bacteria. Cu(naph1pp)2 was further explored in combinatorial tests with ciprofloxacin against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). The combination of Cu(naph1pp)2 and ciprofloxacin is considered additive, i.e., the effect of the two compounds combined is stronger than that of the individual compounds in the equivalent concentration. Three novel naphthyl derived bis-(3-hydroxy-4-pyridinonate) copper(II) complexes were prepared and their antibacterial activity assessed. The most active complex against multidrug-resistant (MDR) isolates was further explored in combinatorial tests with ciprofloxacin revealing an additive effect against Gram-positive MDR isolates. [Display omitted] •Three new copper(II) complexes were prepared and tested against several bacterial strains.•Bis(3-hydroxy-2-methyl-1-naphthyl-4-pyridinonate)copper(II) is defined as Cu(naph1pp)2.•Cu(naph1pp)2 was the most active, including against multidrug-resistant (MDR) isolates.•Cu(naph1pp)2 was further explored in combinatorial tests with ciprofloxacin.•The combination showed an additive effect against Gram-positive MDR isolates.