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Bioinorganic Chemistry and Applications
Volume 2007 (2007), Article ID 98732, 15 pages
http://dx.doi.org/10.1155/2007/98732
Research Article

Complexes of Pd(II) and Pt(II) with 9-Aminoacridine: Reactions with DNA and Study of Their Antiproliferative Activity

1Departamento de Química Inorgànica, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, Barcelona 08028, Spain
2Departamento de Bioquímica i Biologia Molecular, Facultat de Biología, Universitat de Barcelona, avenue Diagonal 645, Barcelona 08028, Spain
3Departamento de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geología, Universitat de Barcelona, C/ Martí i Franquès s/n, Barcelona 08028, Spain

Received 16 March 2007; Accepted 10 May 2007

Academic Editor: Giovanni Natile

Copyright © 2007 X. Riera et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Four new metal complexes {M = Pd(II) or Pt(II)} containing the ligand 9-aminoacridine (9AA) were prepared. The compounds were characterized by FT-IR and H, C, and Pt NMR spectroscopies. Crystal structure of the palladium complex of formulae [Pd(9AA)(μ-Cl)]2·2DMF was determined by X-ray diffraction. Two 9-acridine molecules in the imine form bind symmetrically to the metal ions in a bidentate fashion through the imine nitrogen atom and the C(1) atom of the aminoacridine closing a new five-membered ring. By reaction with phosphine or pyridine, the Cl bridges broke and compounds with general formulae [Pd(9AA)Cl(L)] (where L=PPh3 or py) were formed. A mononuclear complex of platinum of formulae [Pt(9AA)Cl(DMSO)] was also obtained by direct reaction of 9-aminoacridine and the complex [PtCl2(DMSO)2]. The capacity of the compounds to modify the secondary and tertiary structures of DNA was evaluated by means of circular dichroism and electrophoretic mobility. Both palladium and platinum compounds proved active in the modification of both the secondary and tertiary DNA structures. AFM images showed noticeable modifications of the morphology of the plasmid pBR322 DNA by the compounds probably due to the intercalation of the complexes between base pairs of the DNA molecule. Finally, the palladium complex was tested for antiproliferative activity against three different human tumor cell lines. The results suggest that the palladium complex of formula [Pd(9AA)(μ-Cl)]2 has significant antiproliferative activity, although it is less active than cisplatin.