• Dorkov, Petar
• Zhorova, Rumyana
• Simova, Svetlana
• Pantcheva, Ivayla
• Petkov, Nikolay

Abstract

<jats:title>Abstract</jats:title><jats:p>In the present paper the synthesis and structural characterization of alkaline-earth metal(II) complexes of the polyether ionophorous antibiotic salinomycinic acid (SalH.H<jats:sub>2</jats:sub>O) are discussed. The complexes [M(Sal)<jats:sub>2</jats:sub>(H<jats:sub>2</jats:sub>O)<jats:sub>2</jats:sub>] (M = Mg<jats:sup>2+</jats:sup>, <jats:bold>1</jats:bold>; Ca<jats:sup>2+</jats:sup>, <jats:bold>2</jats:bold>; Sr<jats:sup>2+</jats:sup>, <jats:bold>3</jats:bold>; Ba<jats:sup>2+</jats:sup>, <jats:bold>4</jats:bold>) were obtained reacting salinomycinic acid and Et<jats:sub>4</jats:sub>NOH with the corresponding metal(II) salts at metal-to-ligand-to-base molar ratio of 1:1:1. The spectral properties of <jats:bold>1–4</jats:bold> were characterized using infrared spectroscopy, fast atom bombardment-mass spectrometry, nuclear magnetic resonance and elemental analysis data. The crystallinity degree and morphology of complex <jats:bold>2</jats:bold> were studied by X-ray powder diffraction and transmission electron microscopy. The biometal(II) salinomycinate complexes <jats:bold>1</jats:bold> and <jats:bold>2</jats:bold> possess an enhanced antimicrobial activity compared to the parent antibiotic against Gram-positive bacteria. The comparison between the effectiveness of the complexes, reported here, and the already known isostructural coordination species of salinomycin and monensin (MonH.H<jats:sub>2</jats:sub>O), revealed that magnesium(II) and calcium(II) monensinates appear to be promising antibacterial agents against <jats:italic>Bacillus subtilis</jats:italic>, <jats:italic>Bacillus cereus</jats:italic> and <jats:italic>Micrococcus luteus</jats:italic>.</jats:p>

Topics

• morphology
• Magnesium
• Magnesium
• mass spectrometry
• transmission electron microscopy
• Calcium
• crystallinity
• spectrometry
• infrared spectroscopy
• elemental analysis