SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY OF COBALT(III) COMPLEX WITH PHENANTHROLINE AND MALTOSE

ABSTRACT The mononuclear cobalt(III) complex derived from 1,10-phenanthroline and maltose ([Co(phen) 2 maltose]Cl 2 ∙3H 2 O) ( 1 ) has been synthesized and characterized in aqueous solution. Its characterization was based on its optical and spectroscopic properties.The antimicrobial activity of this complex was screened in vitro against the microorganisms Escherichia coli DH5a, Salmonella enterica sv Enteritidis ISP/953, Klebsiella pneumoniae RYC492, Pseudomonas aeruginosa PAO1, Enterococcus faecalis ATCC 29212, Bacillus cereus GCA234, Micrococcus sp. Staphylococcus aureus ATCC25923.Complex ( 1 ) showed antibacterial activity with a bacteriostatic effect over Gram positive and negative bacteria. The cytotoxicity of complex (1) was tested in vitro on human embryonic kidney cells. Keywords: Carbohydrate-cobalt(III) complexes; circular dichroism; antibacterial activity. e-mail: jparada@ciq.uchile.cl 1. INTRODUCTION Transition metal complexes are of interest since they display a wide variety of application in fields ranging from materials science and catalysis to biological activity [1].From the biological point of view, several studies have shown that the complexes may have antibacterial, antifungal and antitumor activity [2].The biological activity of metal complexes is highly dependent on the nature of the metal ions and the donor sequence of the ligands because different ligands exhibit different biological properties [3].An interesting group of ligands are the carbohydrates [4], whose complexes have shown significant antimicrobial activity against Gram-positive and Gram-negative bacterial strains as well as a few fungal strains [5]. Poller and Parkin reported the synthesis of organometallic derivatives of sucrose (lead, tin and germanium). In that study organotin was found to exhibit higher biocidal activities than would be expected from the tin content [6].A few sugar-cobalt complexes with antibacterial activity have been reported. An important example is grafted PVA polymer with a derivative of erythro-ascorbic acid (pentulosono-lactone-2,3-enedianisoate) reported by Salih et al. It was evaluated for antimicrobial properties against four pathogenic bacteria (