DNA CLEAVAGE ACTIVITY OF NOVEL SCHIFF BASE COPPER(II) COMPLEXES WITH SULFUR CONTAINING-LIGANDS: (2-(2-METHYLTHIO)PHENYLIMINO)METHYLPHENOL, N-BENZYLIDINE-2-METHYLTHIOANILINE

Abstract

Objective: To study the DNA cleavage activity of all copper(II) complexes using supercoiled pUC19 DNA by agarose gel electrophoresis.
Methods: In this study, six new schiff base mixed ligand copper(II) complexes containing [Cu(L
1
)(8Hq)Cl
2
], [Cu(L
2
)(8Hq)Cl
],
[Cu(L
2
)(phen)Cl
2
], [Cu(L
1
)(Bpy)Cl
2
], and [Cu(L
2
)(Bpy)Cl
] (where, phen=1,10-phenanthroline, Bpy=2, 2'-bipyridyl, 8Hq=8-hydroxy quinoline, ligand
L
1
=(2-(2-methylthio)phenylimino)methylphenol, ligand L
2
=N-benzylidine-2-methylthioaniline) were synthesized. The six novel schiff base ligands
were characterized by molar conductance, ultraviolet, infrared (IR), and cyclic voltammetry (CV) measurements. Low molar conductance values of
copper(II) complexes showed non-electrolyte in nature. The IR spectral data indicate that nitrogen, sulfur, and azomethine nitrogen coordinate to the
central metal ion. The electrochemical properties such as anodic, cathodic peak potential, and electron transfer process of the complexes were studied
using CV measurements. Based on these spectral data, octahedral geometry was proposed to all copper(II) complexes.
Results: The result confirmed that binding constant value of 13.95 × 10
2
3
M
for complex (VI) suggested good intercalative binding with calf thymus
(CT) DNA. When DNA (pUC19) cleavage analyses was performed, copper(II) complexes - I, II, V, VI showed cleavage activity.
−1
Conclusion: The complexes - III and IV did not exhibit DNA binding as well as DNA cleavage potential which may be due to the presence of
O-phenanthroline.
Keywords: (2-(2-methylthio)phenylimino)methylphenol, N-benzylidine-2-methylthioaniline, Copper(II) complexes, Calf thymus DNA, pUC19 DNA,
DNA binding and cleavage activity.
2
], [Cu(L
1
)(phen)Cl
2