DNA Interaction Studies of a New Platinum(II) Complex Containing Different Aromatic Dinitrogen Ligands.

Nahid Shahabadi,Robabeh Alizadeh,Somaye Mohammadi

doi:10.1155/2011/429241

Nahid Shahabadi, Robabeh Alizadeh + Show 1 more

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https://doi.org/10.1155/2011/429241

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Abstract

A new mononuclear Pt(II) complex, [Pt(DMP)(DIP)]Cl2.H2O, in which DMP is 4,4-dimethyl-2,2-bipyridine and DIP is 4,7-diphenyl-1,10-phenantroline, has been synthesized and characterized by physicochemical and spectroscopic methods. The binding interaction of this complex with calf thymus DNA (CT-DNA) was investigated using fluorimetry, spectrophotometry, circular dichroism, viscosimetry and cyclic voltametry (CV). UV-VIS spectrum showed 4 nm bathochromic shift of the absorption band at 280 nm along with significant hypochromicity for the absorption band of the complex. The intrnisic binding constant (K b = 2 × 104 M−1) is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. The fluorescence studies revealed that the probable quenching mechanism of fluorescence of the complex by CT-DNA is static quenching. The thermodynamic parameters (ΔH > 0 and ΔS > 0) showed that main interaction with hydrogenic forces occurred that is intercalation mode. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed.

Highlights

During the recent years, only some platinum compounds such as cisplatin, carboplatin, and more recently nedaplatin and oxaliplatin have been known as antitumor compounds in clinical treatments; the research in this field is still increasing [1,2,3,4,5]
We report the results of an investigation of the interaction with calf thymus DNA of the complex [Pt(DMP)(DIP)]Cl2·H2O
We investigate synthesis and characterization of new platinum(II) complex, and binding with calf thymus DNA (CT-DNA) was studied

Summary

Introduction

Only some platinum compounds such as cisplatin, carboplatin, and more recently nedaplatin and oxaliplatin have been known as antitumor compounds in clinical treatments; the research in this field is still increasing [1,2,3,4,5]. McFadyen et al [13] synthesized a range of Pt(II) complexes containing substituted phenanthroline ligands and showed that the complex [Pt(en)(3,4,7,8-Me4phen)]Cl2 was two or three times more active than the corresponding phen-based complex [Pt(en)(phen)]Cl2, against murine leukemia cell lines. In this context, we report the results of an investigation of the interaction with calf thymus DNA of the complex [Pt(DMP)(DIP)]Cl2·H2O. UV spectrophotometry, fluorescence method, dynamic viscosity measurements circular dichroism, and cyclic voltametry studies have been preferred because small molecule-DNA interaction may be experimentally monitored by changes in the intensity and position of the spectroscopic peak responses or changes in dynamic viscosity of DNA

Experimental

Results and Discussion

Conclusion