Antibacterial activity of Schiff base ligands containing pyridine and disulphide moieties against some chosen human bacterial pathogens

Abstract

The objective of the study was to evaluate the antibacterial activities of N,N’[1,1’-dithiobis(phenylene)]bis(benzyldeneimine), referred to as L1 and o,o’-(N,N-dipicolinyldene) diazadiphenyldisulfide, referred to as L2, containing disulfide moieties against some ophthalmic pathogens (Klebsiella species, Escherichia coli, Streptococcus species, Proteus morganii, Pseudomonas species, Streptococcus pneumoniae, Acinetobacter species, Streptococcus pyogenes and Streptococcus viridans), urinary tract infectious pathogens (P. morganii, E. coli, Pseudomonas spp., Enterobacter species, and Klebsiella spp.) and antibiotic resistant pathogens (Staphylococcus species, Streptococcus, Pseudomonas spp., and Klebsiella spp.) for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The MIC for the ophthalmic pathogens and antibiotic resistant pathogens were found to be 400 to 500 µg/ml, while for the urinary tract infectious pathogens a lower MIC value (200 µg/ml) was obtained. The MBC for the compounds against all the pathogens tested was 400 to 500 µg/ml. The synthesized Schiff L1 and L2 showed the MIC values for all the tested ophthalmic and antibiotic resistant bacterial pathogens more or less similar. Further studies are needed to prove the safe and efficacy needed for these compounds to develop as a drug after completing successful preclinical and clinical tests. Key words: Antibacterial activity, minimum bactericidal concentration (MBC), minimum inhibitory concentration (MIC), N, N’[1,1’-dithiobis(phenylene)]bis(benzyldeneimine), ophthalmic pathogens, Urinary tract infectious pathogens (UTI), antibiotic resistant pathogens.