Table of Contents
Metal-Based Drugs
Volume 2007 (2007), Article ID 67376, 13 pages
http://dx.doi.org/10.1155/2007/67376
Research Article

Synthesis, Structural Characterization, and Cytotoxic Activity of Novel Paramagnetic Platinum Hematoporphyrin IX Complexes: Potent Antitumor Agents

1Department of Analytical Chemistry, Faculty of Chemistry, St. Kliment Ohridsky University of Sofia, 1 J. Bourchier Boulevard, Sofia 1164, Bulgaria
2Department of Pharmacology and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav, Sofia 1000, Bulgaria
3Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Street Bl. 11, Sofia 1113, Bulgaria
4Departamento de Fisica, Institució Catalana de Recerca i Estudis Avancats (ICREA), Universitat Autònoma de Barcelona, Bellaterra 08193, Barcelona, Spain

Received 9 February 2007; Accepted 9 May 2007

Academic Editor: Irena Kostova

Copyright © 2007 G. Gencheva 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

Three novel stable Pt(III) complexes with distorted octahedral structure and (dz2)1 ground state have been obtained in the course of Pt(II)-hematoporphyrin IX ((7,12-bis(1-hydroxyethyl)-3,8,13,17-tetramethyl-21H-23H-porphyn-2,18-dipropionic acid), Hp) interaction in alkaline aqueous medium and aerobic conditions. A redox interaction also takes place together with the complexation process leading to the formation of Pt(III) species and organic radicals. The processes in the reaction system and the structure of the complexes formed cis-[Pt(III)(NH3)2(Hp3H)(H2O)2]H2O1, [Pt(III)(Hp3H)(H2O)2]H2O2, and [Pt((O,O)Hp2H)Cl(H2O)3] 3, were studied by UV-Vis, IR, EPR and XPS spectra, thermal (TGS, DSC), potentiometric and magnetic methods. The newly synthesized complexes show promising cytotoxic activity comparable with that of cis-platin in in vitro tests against a panel of human leukemia cell lines. The observed cytotoxicity of the complex 2 against SKW-3 cells (KE-37 derivative) is due to induction of cell death through apoptosis.