Author/Authors :
Shahraki, Somaye Department of Chemistry - University of Sistan & Baluchestan, Zahedan , Mansouri-Torshizi, Hassan Department of Chemistry - University of Sistan & Baluchestan, Zahedan , Sori Nezami, Ziba Department of Chemistry - University of Sistan & Baluchestan, Zahedan , Ghahghaei, Arezou Department of Biology - University of Sistan & Baluchestan, Zahedan , Yaghoubi, Fatemeh Department of Chemistry - University of Sistan & Baluchestan, Zahedan , Divsalar, Adeleh Department of Biological Sciences - Tarbiat Moallem University, Tehran , Saboury, Ali-Akbar Institute of Biochemistry and Biophysics - University of Tehran, Tehran , Shirazi, Farshad H Pharmaceutical Sciences Research Center - Shahid Behesthi University of Medical Sciences, Tehran
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 CTDNA
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.
