New 4′-(4-chlorophenyl)-2,2′:6′,2″-terpyridine ruthenium(II) complexes: Synthesis, characterization, interaction with DNA/BSA and cytotoxicity studies

Abstract

In this study, we have developed a series of new monofunctional Ru(II) complexes of the general formula mer-[Ru(Cl-Ph-tpy)(N-N)Cl]Cl in which Cl-Ph-tpy is 4'-(4-chlorophenyl)-2,2':6',2″-terpyridine, N-N is a bidentate chelating ligand (1,2-diaminoethane (en, 1), 1,2-diaminocyclohexane (dach, 2) or 2,2'-bipyridine (bpy, 3)). All complexes were fully characterized by elemental analysis and spectroscopic techniques (IR, UV-Vis, 1D and 2D NMR). Their chemical behavior in aqueous solution was studied by UV-Vis and NMR spectroscopy showing that all compounds are relatively labile leading to the formation of the corresponding aqua species 1aq-3aq. Their DNA binding ability was evaluated by UV-Vis spectroscopy, fluorescence quenching measurements and viscosity measurements. Competitive studies with ethidium bromide (EB) showed that the complexes can displace DNA-bound EB, suggesting strong competition with EB (K=1.1-2.7×10M). These experiments show that the ruthenium complexes interact with DNA via intercalation. The complexes bind to serum protein albumin displaying relatively high binding constants (K=10-10M). Compound 3 displayed from high to moderate cytotoxicity against two cancer cell lines HeLa and A549 (with ICca. 12.7μM and 53.8μM, respectively), while complexes 1 and 2 showed only moderate cytotoxicity (with ICca. 84.8μM and 96.3μM, respectively) against HeLa cells. The cell cycle analysis (by flow cytometry) of HeLa and A549 cells treated with complex 3 shows minor changes on the cell cycle phase distribution.

Antimicrobial Activity and DNA/BSA Binding Affinity of Polynuclear Silver(I) Complexes with 1,2-Bis(4-pyridyl)ethane/ethene as Bridging Ligands

“…erefore, the studies aimed at the binding of biologically active compounds with this protein provide useful information on their biodistribution, toxicity, and mechanism of action [52]. Bovine serum albumin (BSA) represents the structural analog of the human serum albumin (HSA) and is the most extensively studied serum albumin for metal complexes interactions [53]. It contains three fluorophores, namely, tryptophan, tyrosine, and phenylalanine; nevertheless, the intrinsic fluorescence of BSA is mainly due to tryptophan alone [54].…”

Studies on DNA Interactions and Biological Activities of Lanthanum(III) Complexes with 4-Quinoline Terpyridine and 1,10-Phenanthroline

“…All the complexes showed significant antibacterial activities against all the tested bacteria [41]. These results suggested that the cytotoxicity depends upon the nature of bidentate and tridentate ligand coordinated to the metal center [42]. Fig.…”

In Vitro Biomolecular Interaction Studies and Cytotoxic Activities of Newly Synthesised Copper(II) Complexes Bearing 2‐Hydroxynaphthaldehyde‐Based Thiosemicarbazone

“…The above‐observed phenomenon may be due to the changes in protein tertiary structure that make some changes environment of tryptophan of BSA, thus indicating the interactions of complexes C1 and C2 to the albumin . The redshift infers the formation of the metal complex‐ BSA adducts, which changed the polarity of the microenvironment in the locality of tryptophan …”