Chemical, spectroscopic characterization, and in vitro antibacterial studies of a new gold(I) complex with N-acetyl-L-cysteine

Abstract

A new gold(I) complex with N-acetyl-L-cysteine was synthesized and characterized by chemical and spectroscopic techniques. The elemental and thermal analyses of the solid compound fit to the composition AuC 5 H 8 NO 3 S Á 0.75H 2 O. Solid-state 13 C-nuclear magnetic resonance (SSNMR) and infrared (IR) analyses indicate the coordination of the ligand to Au(I) through sulfur. The insolubility of the complex in both polar and non-polar solvents supports a polymeric structure. The antibacterial activity of the complex was evaluated by antibiogram assays using the disc diffusion method. The compound showed effective antibacterial activity against Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) bacterial cells.

Chemical, spectroscopic characterization and antibacterial activities in vitro of a novel gold(I)–ibuprofen complex

“…Pure sodium ibuprofenate did not exhibit antibacterial activity against E. coli, P. aeruginosa and S. aureus in the same experimental conditions. The observed activity of Au(I)-ibuprofen against Grampositive (S. aureus) and Gram-negative microorganisms is similar to the antimicrobial behavior of two phosphine-gold(I) complexes with 2-mercaptopropionic and 6-mercaptonicotinic acids [18] and also of a gold(I) complex with N-acetyl-L-cysteine [6]. Although the mechanism of action of the Au(I)-ibuprofen complex remains uncertain, the observed result warrants further studies concerning the application of the gold(I)-ibuprofen compound as a novel antibacterial agent.…”

“…Elsome and coworkers described the antimicrobial activities in vitro and in vivo of a new gold(I)-phosphine complex against Gram-negative bacteria [5]. More recently, new gold(I) and silver(I) complexes with the amino acid N-acetyl-L-cysteine, which show antibacterial activities in vitro against Gram-positive and Gram-negative bacteria, were synthesized in our laboratories [6,7]. Also, a silver(I) complex with acesulfame was evaluated and preliminary biological studies revealed its antimicrobial activity against Mycobacterium tuberculosis as well as against Gram-positive and Gram-negative bacteria [8].…”

Gold complexes as antimicrobial agents: an overview of different biological activities in relation to the oxidation state of the gold ion and the ligand structure

“…Regarding tetrahedral gold(I) complexes, [Au(cis-Ph 2 P(CHvCH)PPh 2 ) 2 ]Cl (35) and [Au(Ph 2 P(CH 2 ) 3 PPh 2 ) 2 ]Cl (36) (Fig. 4b), with chelating diphosphine ligands have been reported to manifest modest activities against Staph.…”

Pathogenic Gram-positive bacteria are highly sensitive to triphenylphosphanegold(O-alkylthiocarbamates), Ph3PAu[SC(OR)=N(p-tolyl)] (R = Me, Et and iPr)

“…The majority of research in this area has in fact focussed upon analogues of Auranofin®, i.e. phosphanegold(I) thiolates [24][25][26][27], but with attention also being directed to the study of N-heterocyclic carbene [28], thiolate [29] and carboxylate [30,31] derivatives. Relatively less consideration has been devoted to gold(III) species [32].…”