In vitro antimicrobial activity and cytotoxicity of nickel(II) complexes with different diamine ligands

Three diamines, 1,3-propanediamine (1,3-pd), 2,2-dimethyl-1,3-propanediamine (2,2-diMe-1,3-pd) and (+/-)-1,3-pentanediamine (1,3-pnd), were used for the synthesis of nickel(II) complexes 1-3, respectively, of the general formula [Ni(L)(2)(H2O)(2)]Cl-2. The stoichiometries of the complexes were confirmed by elemental microanalysis, and their structures were elucidated by spectroscopic (UV-Vis and IR) and molar conductivity measurements. The complexes 1-3, along with NiCl2 center dot 6H(2)O and the diamine ligands, were evaluated against a panel of microbial strains that are associated with skin, wound, urinary tract and nosocomial infections. The obtained results revealed no significant activity of 1-3 against the investigated bacterial strains. On the other hand, they showed good antifungal activity against pathogenic Candida strains, with minimum inhibitory concentration (MIC) values in the range from 15.6 to 62.5 mu g mL(-1). The best anti-Candida activity was observed for complex 2 against C. parapsilosis, while the least susceptible to the effect of the complexes was C. krusei. The antiproliferative effect on normal human lung fibro-blast cell line MRC-5 was also evaluated in order to determine the therapeutic potential of nickel(II) complexes 1-3. These complexes showed lower negative effects on the viability of the MRC-5 cell line than the clinically used nystatin and comparable selectivity indexes to that of this antifungal drug.