title: Efficient interrupting skills of amino acid metallointercalators with DNA at physiological pH: evaluation of biological assays.
abstract: The 4-aminoantipyrine derivatives (NO2, OCH3) and their mixed-ligand complexes with amino acids have been synthesized and investigated for their binding with CT DNA using UV-visible spectroscopy, cyclic voltammetry, and viscosity measurements under physiological conditions of pH (stomach 4.7; blood 7.4). The results from all techniques i.e. binding constant (Kb), and free energy change (ΔG) were in good agreement and inferred spontaneous compound-DNA complexes formation via intercalation. Among all the compounds 1 and 4 showed comparatively greater binding at pH 7.4 as evident from its greater Kb values. All the complexes exhibit oxidative cleavage of supercoiled (SC) pBR322 plasmid DNA in the presence of H2O2 as an activator. It is remarkable that at 25μM concentration 1 and 4 completely degrade SC DNA into undetectable minor fragments and thus they act as efficient chemical nucleases. Among the new complexes, complexes 1 and 4 have highest potential against all the microorganisms tested. The results of the above biological experiments also reveal that the choice of different metal ions has little influence on the DNA binding, DNA cleavage and antimicrobial assay.
authors.affiliation: Research Department of Chemistry, VHNSN College, Virudhunagar 626 001, Tamil Nadu, India. Electronic address: ramchem1964@gmail.com.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Raman
authors.affiliation: Research Department of Chemistry, VHNSN College, Virudhunagar 626 001, Tamil Nadu, India.
authors.forename: Muthusamy
authors.initials: M
authors.lastname: Selvaganapathy
authors.affiliation: Central Electrochemical Research Institute, Karaikudi 630 006, Tamil Nadu, India.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Radhakrishnan
mesh_terms: D000675:Ampyrone / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development*; D004247:DNA / Q000737:chemistry*; D005658:Fungi / Q000254:growth & development*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007364:Intercalating Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D019216:Metals, Heavy / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D007364:Intercalating Agents; D019216:Metals, Heavy; D000675:Ampyrone; D004247:DNA; D006861:Hydrogen Peroxide
keywords: Antimicrobial assay; Binding constant; Intercalation; Oxidative cleavage