Platinum Cyclooctadiene Complexes with Activity against Gram-positive Bacteria

Area of Science:

• Inorganic medicinal chemistry
• Antimicrobial research
• Drug discovery

Background:

• Antimicrobial resistance poses a significant global health threat.
• Organic chemistry approaches are insufficient for novel antibiotic development.
• Metal-containing compounds show promise for antimicrobial applications.

Purpose of the Study:

• To investigate the antibacterial properties of platinum cyclooctadiene (COD) complexes.
• To evaluate the toxicity and efficacy of these novel compounds.
• To explore potential therapeutic applications against resistant bacteria.

Main Methods:

• Synthesis and characterization of 15 platinum cyclooctadiene (COD) complexes.
• In vitro testing against Gram-positive bacteria, including resistant strains.
• In vitro and in vivo toxicity assessments using mammalian cells and Galleria mellonella.
• Preliminary in vivo efficacy studies and serum binding analysis.

Main Results:

• Pt(COD)X2 complexes (X=Cl, I, Pt1, Pt2) demonstrated excellent activity against Gram-positive bacteria, including vancomycin-resistant and methicillin-resistant Staphylococcus aureus.
• Lead compounds exhibited no toxicity to mammalian cells or hemolytic activity at tested concentrations.
• Compounds showed no toxicity in the Galleria mellonella model.
• Preliminary in vivo studies showed no reduction in bacterial load, attributed to high serum binding and low bioavailability.

Conclusions:

• Platinum cyclooctadiene (COD) complexes represent a promising class of compounds with potent antibacterial activity.
• The observed in vitro efficacy is specific to bacteria and not due to general toxicity.
• High serum binding limits in vivo bioavailability, suggesting topical administration as a potential delivery route.