A molybdenum-ciprofloxacin complex with an isopolyoxometalate having DNA binding and antibacterial activity

Abstract

In this study, an antibacterial complex based on the quinolone antibacterial drug ciprofloxacin (CF) and a polyoxometalate was synthesized, Mo₂O₅(CF)₂(CFd)₂(β-Mo₈O₂₆)·5H₂O (1). Complex 1 was characterized by elemental analysis and X-ray single-crystal diffraction. Single-crystal structural analysis revealed that 1 was made of β-Mo₈ clusters, binuclear molybdenum clusters Mo₂O₅(CF)₂(CFd)₂, and water molecules. The antibacterial activity of 1 has been tested against three microorganisms (Staphylococcus aureus, Escherichia coli, and Bacillus subtilis strains); the antibacterial activities of 1 were higher than those of free CF at the same mass amounts. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated using Uv-vis spectroscopy to determine the binding constants. The results indicated that intercalation is the probable mode of action, with 1 demonstrating higher binding constants (K_b) to CT-DNA (1.8 × 10⁵ M⁻¹) compared to pure CF (4.9 × 10⁴ M⁻¹). These findings show that the implementation of molybdate for ciprofloxacin modification resulted in the formation of a metal complex with enhanced antibacterial activity over CF and significantly improving its binding affinity to DNA.

Keywords:

• Complexes
• ciprofloxacin
• polyoxometalate
• antibacterial
• DNA binding

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Natural Science Foundation of Heilongjiang Province (Grant number LH2021B028).