DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes

Few transition metal complexes of tetradentate N2O2 donor Schiff base ligands containing 2-hydroxybenzylidene-4-aminoantipyrine and amino acids (alanine/valine) abbreviated to KHL1/KHL2 have been synthesized. All the metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The Schiff bases KHL1/KHL2 are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around the metal ions. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through minor groove binding mode. The studies on mechanism of photocleavage reveal that singlet oxygen (1O2) and superoxide anion radical (O2-) may play an important role in the photocleavage. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae and antifungal activities against Aspergillus niger, Fusarium solani, Culvularia lunata, Rhizoctonia bataicola and Candida albicans by MIC method.

Graphical abstractAmino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes are valuable in designing novel agents for targeting nucleic acids as well as setting the stage for the synthesis of chemical anticarcinogenic drugs.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of a new family of amino acid based complexes. ► They were found to act as good minor groove binders. ► These chelates exhibit efficient cleavage potential of pUC19 DNA. ► To develop the novel design of new metallonucleases.