Evaluating the antibacterial activity of muramyl dipeptide derivatives, retro-tuftsin derivatives, and anthraquinone oligopeptides against a range of pathogenic bacteria

Abstract

Search for new and efficient antibiotic is crucial because of microbial drug resistance and problems with side effects of the administered medication. In this study, we evaluate the in vitro microbiological activity of muramyl dipeptide derivatives, retro-tuftsin derivatives (i.e., tuftsin with reversed amino acid sequences), and combinations of retro-tuftsin derivatives with substituted anthraquinones. The potency of the investigated derivatives towards methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae ESBL (extended-spectrum β-lactamases) was compared based on the spectroscopically-measured minimal inhibitory concentrations (MIC values). The bacterial growth have also been studied with different concentrations of compounds. Statistical analysis of the results revealed that certain modifications lead to promising activity against S. aureus (anthraquinone analogue – 3c and retro-tuftsin derivative – 2b), while other derivatives exhibit activity against P. aeruginosa (muramyl dipeptide derivative – 1d and retro-tuftsin derivative – 2b). The obtained results of microbiological activity indicate that the structure of the tested compounds may be the basis for further modifications.

Regulation of Immune Homeostasis via Muramyl Peptides-Low Molecular Weight Bioregulators of Bacterial Origin

“…The direct effect of muramyl peptides and their analogues on five bacterial strains of four species (S. aureus MRSA/MSSA, K. pneumoniae ESBL, P. aeruginosa and E. coli) revealed that the value of the minimum inhibitory concentration (MIC) was >512 µg/mL against all strains except for Pseudomonas aeruginosa (P. aeruginosa), for which the MIC was 128 µg/mL. As a comparison, the MICs of antibiotics (kanamycin, tetracycline, and chloramphenicol) in this experiment ranged from 1 to 32 µg/mL [36]. Muramyl peptides can be used by bacteria for communication [37], participating in the coordination of the growth of the entire population and acting, along with other low molecular weight bioregulators of bacterial origin, as a quorum-sensing mediator.…”