Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin

Abstract

BackgroundThe natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II) and lead(II).ResultsNew metal(II) complexes of the polyether ionophorous antibiotic salinomycin with Cd(II) and Pb(II) ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa) undergoes a reaction with heavy metal(II) ions to form [Cd(Sal)2(H2O)2] (1) and [Pb(Sal)(NO3)] (2), respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II) ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II) center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II) cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation.ConclusionThe formation of the salinomycin heavy metal(II) complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock farming.

Spectral properties and biological activity of La(III) and Nd(III) Monensinates

“…It was observed that at a metal-to-ligand molar ratio of 1:3 a solid phase forms, but it gradually dissolves as the increased concentration of the metal(III) ion was added. The composition of the solid phase was suggested to belong to the neutral species of general formula of [Ln(Mon) 3 (H 2 O) 3 ] (Ln = La 3+ (1), Nd 3+ (2)) based on our previous studies of ligand reactivity towards divalent metal ions [20][21][22][23][24][25][26][27] and Gd 3+ [35]. Elemental analysis data ( Table 1) align with the proposed composition of metal(III) complexes.…”

“…Since 2008, broad research on potential ability of polyether ionophores to bind metal ions of higher oxidation state has been performed at Sofia University [20][21][22][23][24][25][26][27]. It was found that Monensin forms various complexes depending on the ligand form and origin of the metal ions.…”

Crystal structure and Hirshfeld surface analysis of dichlorido{2,2′-[oxybis(methylidene)]dipyridine}mercury(II)

“…Structural comparisons of group 12 metal ions in similar environments can help improve understanding of the effects of metal-ion replacement on the biological properties of organic molecules. Ether-containing bioactive compounds with group 12 metal ion-dependent bioactivity include flavonoids (Sreenivasulu et al, 2010;Kim et al, 2011;Li et al, 2017), ionophores (Ivanova et al, 2011), and pharmaceuticals (Zhang et al, 2014). Recent studies of 2,2 0 -[oxybis(methylidene)]dipyridine (L) with group 12 perchlorate salts revealed bistridentate chelate [ML 2 ](ClO 4 ) 2 complexes with either meridional octahedral (M = Zn 2+ or Cd 2+ ) or trigonal-prismatic (M = Hg 2+ ) metal-ion coordination (Sturner et al, 2022).…”

Novel Cerium(IV) Coordination Compounds of Monensin and Salinomycin

“…It targets not only the tumor cells but also the cancer stem cells which are responsible for metastasis processes. On the other hand, salinomycin is an attractive chelating agent and there are several studies dedicated to the synthesis of different metal-based derivatives [ 34 , 35 , 36 , 37 ]. Monensin is also a subject of extensive studies although it has not been used in human medicine yet.…”