Metal-based biologically active compounds: design, synthesis, medicinal, toxicity and DNA interaction assay

Abstract

The mixed-ligand oxovanadium complexes with 3-(diphenylphosphino)-propionic acid and various fluoroquinolones have been prepared. Physical (magnetic susceptibility, molar conductance and themogravimetry), spectral (IR, ESI–MS, EPR and electronic) and analytical data have established the structures of synthesized oxovanadium(IV) complexes. The electronic absorption spectra, ESR spectra and magnetic susceptibility measurements of the complexes indicate square-pyramidal geometry for all oxovanadium(IV) complexes. The DNA binding characteristics of the complexes have been investigated by absorbance and viscosity measurements. Photophysical studies reveal that the complexes interact with calf thymus DNA with an intrinsic binding constant about 2–9 × 105 M−1. The DNA cleavage activity has been carried out by gel electrophoresis experiment using supercoiled form of pUC19 DNA under aerobic conditions, and all the complexes show efficient cleavage of DNA. The antimicrobial activities of the complexes were screened against three gram-negative and two gram-positive microorganisms in terms of minimum inhibitory concentration (MIC). All the complexes screened for MIC against tuberculosis. The activity data show that the metal complexes have a promising biological activity comparable with the parent ligand and fluoroquinolones.