Interaction of bis(alkylamine)dichloropalladium(II) complexes with CT-DNA and BSA; their synthesis, characterization, antitumor, and antibacterial evaluations

Abstract

A series of five new and analogous palladium(II) alkylamine complexes of cisplatin derivatives such as cis-[Pd(alkyl-am)2Cl2], where alkyl-am is Ethyl-, Propyl-, Butyl-, Hexyl-, and Octyl-amine, have been prepared. They have been characterized by physicochemical methods such as FT-IR, 1H-NMR, UV-Vis, conductivity measurements and elemental analysis. These synthesized metal complexes were screened for their in-vitro antitumor activity against human MOLT-4 cells. Only [Pd(Octyl-am)2Cl2] showed moderate activity. They were also tested against some gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria by measuring the values of IZ, MIC and MBC. All Pd(II) complexes displayed comparable activity with that of cefazoline as standard antibiotics. To clarify the mode of interaction between these compounds and CT-DNA and (BSA), their interaction behavior was checked using electronic absorption spectroscopy. Results indicated that all of the above mentioned Pd(II) complexes effectively interacted with CT-DNA and BSA at low concentration and the distance between the interacted Pd(II) complexes and BSA were in the range of 3.00–3.30 nm. Fluorescence emission studies revealed that the complexes quenched CT-DNA pretreated with methylene blue (MB) and the intrinsic fluorescence of BSA through static quenching procedure. Using the binding constant (K b) obtained from fluorescence studies, thermodynamic parameters (ΔG°, ΔH° and ΔS°) suggested that hydrogen bonding and van der Waals forces, as well as hydrophobic interaction, play the major role between metal complexes with CT-DNA and BSA. In all cases the binding forces were spontaneous owing to –ΔG°. Communicated by Ramaswamy H. Sarma