Activity of a Novel Antimicrobial Peptide with Nitric Oxide Induction against some Pathogenic Bacteria

Document Type : Original Article


1 Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran


Introduction: Bacterial resistance against antibiotics has caused many problems in treating humans and animal infections worldwide. Nowadays, researchers are continuously seeking to develop novel antibacterial to tackle the issue of microbial resistance. Antimicrobial peptides have been introduced as new effective strategies that kill bacteria quickly and cause less antibiotic resistance. In this study, we evaluated the antibacterial and cytotoxic effects of a synthesized peptide (NRWCFAGRR-NH2) on some Gram-positive and –negative bacteria and eukaryotic cells.
Materials and Methods: Twelve bacterial strains were selected to study the antimicrobial effect of the NRWC peptide. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were used to study the bacteriostatic and bactericidal activity of these peptides, respectively. The cytotoxic effect of the peptide was evaluated on Hela cell line and human RBC using the MTT assay and hemoglobin release measurement, respectively. The J774 macrophage cell line was used to measure nitric oxide production in response to the peptide.
Results: The results showed that NRWCFAGRR peptide has a bactericidal and inhibitory effect on all 12 bacterial strains' growth in a dosedependent manner. It has also been proven that the toxic effect of the peptide on human cells is evitable at the MIC and MBC concentration. The highest amount of nitric oxide production was induced after 48 hours of treatment.
Conclusions: Considering the research conducted in the field of antimicrobial peptides, our designed peptide has antimicrobial properties that kill some of the pathogenic microorganisms directly and can theoretically kill some organisms indirectly via induction of nitric oxide by macrophages.