Abstract

ANTIMICROBIAL ACTIVITIES, DNA CLEAVAGE STUDIES OF NEW SCHIFF BASE Cu(II), Zn(II) AND Ni(II) METAL COMPLEXES DERIVED FROM 2,4-DIHYDROXYBENZALDEHYDE AND P-PHENYLENEDIAMINE

P. Subramanian¹* and M.Vijayalakshmi²

ABSTRACT

The new Schiff base ligand and its metal complexes synthesised from 2,4-dihydroxy benzaldehyde and p-phenylenediamine were screened for their in-vitro antimicrobial activities against one gram positive bacteria and two gram negative bacteria (Staphylococcus aureus, Klebsiela pneumoniae and Eschrichia coli) and have been carried out using nutrient agar as medium. The zones of inhibition of the synthesized complexes are compared with that of free ligand, the standard streptomycin and have been discussed. These studies revealed that the new Schiff base complexes were found to be more active than the Schiff base ligand. The pUC18 DNA cleavage study was monitored by gel electrophoresis method. From this study, it was found that the complex cleaves pUC18 DNA in presence of the oxidant H2O2. New metal complexes of Cu(II), Zn(II) and Ni(II) were synthesised from the ligand prepared from 2,4-dihydroxy benzaldehyde and p-phenylenediamine. Their physicochemical properties were investigated using elemental and thermal analyses, IR, conductometric and magnetic susceptibility measurements. The conductance data reveal that all the complexes are non electrolyte in nature. IR spectra showed that the ligand is coordinated to the metal ions in a tetra-dentate manner with N2O2 donor sites of the phenolic OH and azomethine N.

Keywords: Antimicrobial, pUC18 DNA cleavage, Schiff base ligand, Metal Complexes.