N, N-dimethylbiguanide complexes displaying low cytotoxicity as potential large spectrum antimicrobial agents

Abstract

The new complexes M(DMBG) 2(ClO 4) 2 (M:Mn, Ni, Cu and Zn; DMBG: N, N-dimethylbiguanide) have been synthesized and characterized by IR, EPR, 1H NMR, 13C NMR as well as electronic spectroscopy data. Complex [Ni(DMBG) 2](ClO 4) 2·2DMF (DMF: N, N-dimethylformamide) crystallizes in the monoclinic P2(1)/c space group while [Cu(DMBG) 2](ClO 4) 2 adopt monoclinic P21/c space group as X-ray single crystal data indicate. The redox behavior of complexes was investigated by cyclic voltammetry. The metal-free N, N-dimethylbiguanide and complexes exhibit specific anti-infective properties as demonstrated the low MIC values, a large antimicrobial spectrum and also inhibit the ability of Pseudomonas aeruginosa and Staphylococcus aureus strains to colonize the inert surfaces. The complexes exhibit also a low cytotoxicity levels on HeLa cells.