Antimicrobial Activity of Some New Thioureides Derived from 2-(4-Chlorophenoxymethyl)benzoic Acid

Abstract

We report here the characterisation of eight newly synthesized thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid and the evaluation of the in vitro antimicrobialactivity of the new compounds against Gram-positive [Listeria monocytogenes,Staphylococcus aureus, Bacillus subtilis], Gram-negative [Psedomonas aeruginosa,Escherichia coli, Salmonella enteritidis], as well as Candida spp., using both reference andclinical multidrug resistant strains to establish the minimal inhibitory concentration (MIC)values. Our results showed that the tested compounds exhibited specific antimicrobialactivities, both concerning the spectrum of antimicrobial activity and the correspondingMIC values, which ranged widely between 1024 and 32 μg/mL, depending on the natureand position of the substituents on the benzene ring. The most active compounds were N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(2,6-dichlorophenyl)-thiourea (5g) and N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(4-bromophenyl)-thiourea (5h), which showed a broadspectrum of antimicrobial activity against enterobacterial strains (E. coli and S. enteritidis),P. aeruginosa, S. aureus and Candida spp. All the tested compounds except 5f were highly active against S. aureus (MIC=32 μg/mL), suggesting their possible use in the treatment ofMRSA infections. Four of compounds also exhibited antifungal activity (MIC =256-32μg/mL) against C. albicans, but L. monocytogenes as well as B. subtilis were resistant toall tested compounds. Our studies thus demonstrated that among other biological activities,the thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid also exhibit selective andeffective antimicrobial properties that could lead to the selection and use of thesecompounds as efficient antimicrobial agents, especially for the treatment of multidrugresistant infections.