Synthesis, Spectral Properties, Antibacterial and Antitumor Activity of Salinomycin Complexes with the Transition Metal Ions Co(II), Ni(II), Cu(II) and Zn(II)

SalNa (sodium salinomycin) reacts with divalent transition metal ions of Co(II), Ni(II), Cu(II) and Zn(II) to produce novel compounds characterized by various spectroscopic methods. The interaction of metal (II) ions with SalNa results in the formation of mononuclear complexes of a general composition of [M(Sal)2·(H2O)2] nH2O (n = 0 or 2) where the divalent cations replace Na ions from the cavity of initial compound. The new compounds (disalinomycinates) possess an enhanced antibacterial activity against Gram-positive microorganisms as compared to both SalNa and SalH (salinomycinic acid), respectively. The metal (II) complexes manifest strong concentration dependent cytotoxic effect in experiments using human leukemia cell lines. The complexes of Co(II) and Cu(II) proved to exert superior activity as compared to the Ni(II) and Zn(II) analogues and are much more cytotoxic than SalNa and SalH. Further studies should be conducted to determine the therapeutic indexes of the new compounds.