title: The Effects of Extending of Co-planarity in a Series of Structurally Relative Polypyridyl Palladium(II) Complexes on DNA-binding and Cytotoxicity Properties.
abstract: In depth interaction studies between calf thymus deoxyribonucleic acid (CT-DNA) and a series of four structurally relative palladium(II) complexes [Pd(en)(HB)](NO3)2 (a-d), where en is ethylenediamine and heterocyclic base (HB) is 2,2'-bipyridine (bpy, a); 1,10-phenanthroline (phen, b); dipyridoquinoxaline (dpq, c) and dipyridophenazine (dppz, d) (Figure 1), were performed. These studies have been investigated by utilizing the electronic absorption spectroscopy, fluorescence spectra and ethidium bromide (EBr) displacement and gel filtration techniques. a-d complexes cooperatively bind and denature the DNA at low concentrations. Their concentration at midpoint of transition, L1/2, follows the order a >> b > c > d. Also the g, the number of binding sites per 1000 nucleotides, follows the order a >> b ~ c > d. EBr and Scatchard experiments for a-d complexes suggest efficient intercalative binding affinity to CT-DNA giving the order: d > c > b > a. Several binding and thermodynamic parameters are also described. The biological activity of these cationic and water soluble palladium complexes were tested against chronic myelogenous leukemia cell line, K562. b, c and d complexes show cytotoxic concentration (Cc50) values much lower than cisplatin.
authors.affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran.
authors.forename: Somaye
authors.initials: S
authors.lastname: Shahraki
authors.affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Mansouri-Torshizi
authors.affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran.
authors.forename: Ziba
authors.initials: Z
authors.lastname: Sori Nezami
authors.affiliation: Department of Biology, University of Sistan & Baluchestan, Zahedan, Iran.
authors.forename: Arezou
authors.initials: A
authors.lastname: Ghahghaei
authors.affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Yaghoubi
authors.affiliation: Department of Biological Sciences, Tarbiat Moallem University, Tehran, Iran.
authors.forename: Adeleh
authors.initials: A
authors.lastname: Divsalar
authors.affiliation: Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
authors.forename: Ali-Akbar
authors.initials: AA
authors.lastname: Saboury
authors.affiliation: Pharmaceutical Sciences Research Center, Shahid Behesthi University of Medical Sciences, Tehran, Iran.
authors.forename: Farshad
authors.initials: F
authors.lastname: H Shirazi
keywords: Cytotoxicity; DNA binding; Pd(II) complexes