Tuning the reaction products of ruthenium and ciprofloxacin for studies of DNA interactions

Abstract

This work presents two potential metallo-drugs, the ionic (C 17 H 19 FN 3 O 3 ) 3 [RuCl 6 ] Á 3H 2 O (1) and the coordination [Ru(C 17 H 17 FN 3 O 3 ) 3 ] Á 4H 2 O (2) compounds, obtained by the combination of ruthenium(III) and ciprofloxacin in different synthetic conditions. The ESI MS spectrum of 1 displayed a main peak at m/z ¼ 994.6, assigned to the gaseous phase adduct (ciprofloxacin) 3 Á H þ , while 2 featured peaks at m/z 1093.3 and 547.1 ascribed to [Ru(C 17 2þ . Thermal analysis corroborated the proposed water content for both complexes. Absorption spectra of the compounds in aqueous medium are dominated by ciprofloxacin transitions in the UV region but displayed weak bands in the visible region, assigned to ligand field transitions. The cyclic voltammograms of 2 exhibited a quasi-reversible process ascribed to the Ru(II)/(III) redox pair at À0.25 V (vs. SHE) while 1 displayed this process at À0.11 V, showing that the central ruthenium ion is stabilized in the (III) oxidation state by the coordination to the hard oxygen atoms of ciprofloxacin. The solubility of 1 is pH dependent (as well as free ciprofloxacin) while 2 is fully water soluble and stable under physiological pH for at least 48 h. The compounds are also stable under incubation conditions (stomach pH and 37 C) without significant pH lowering. An interaction study of 2 with ct-DNA showed a value of K b ¼ 2.47 (AE0.89) Â 10 4 mol À1 L for the intrinsic binding constant.

Synthesis, characterization and DNA-binding properties of Ru(II) complexes coordinated by ofloxacin as potential antitumor agents

“…Studies by our research group also found that Ru(II)-polypyridyl complexes with tFMPIP (=2-(trifluoromethylphenyl)-1H-imidazo[4,5f][1, 10]-phenanthroline) can regulate the expression of the Bcl-2 family protein to induce apoptosis of tumor cells through the caspase signal pathway [14]. Whether Ru(II)-polypyridyl complexes with ofloxacin can also exhibit antitumor activity would be a significant finding [15].…”

Metal Complexes of Quinolone Antibiotics and Their Applications: An Update

“…Other chloromethalates, such as enrofloxacinium tetrachloroferate (II), (erxH 2 )[FeCl 4 ]Cl [130], ciprofloxacinium tetrachlorozincate (II) dihydrate, [C 17 H 19 N 3 O 3 F] 2 [ZnCl 4 ]·2H 2 O [131], ciprofloxacinium tetrachloroaurate (III) monohydrate, (CfH 2 )[AuCl 4 ]· H 2 O [132] and ciprofloxacinium hexachlororuthenate (III) trihydrate, (CfH 2 + ) 3 [RuCl 6 ]·3H 2 O [78] were also reported.…”

Cytotoxic, DNA binding, DNA cleavage and antibacterial studies of ruthenium–fluoroquinolone complexes

“…7,8 In recent years, a lot of work has been done on the interaction of the quinolones pefloxacin, ofloxacin and sparfloxacin with diverse metal ions. [9][10][11][12][13][14][15][16][17] In continuation of our previous work, 18 this paper mainly focuses on exploring the trend in DNA-binding affinities of six complexes and the important differences in some related properties. Understanding the features that contribute to recognition of DNA by small ligands or metal complexes is crucial for the development of drugs targeted at DNA.…”