Isolation and Chemical Characterization of an Alpha-Helical Peptide, Dendrocin-ZM1, Derived from Zataria multiflora Boiss with Potent Antibacterial Activity

Today, resistance of microorganisms to antibiotics has become a major challenge. To overcome this problem, development of new drugs, besides research on their antibacterial activity, is essential. Among chemical components, antimicrobial peptides (AMPs) exhibit antibacterial activity and can be selected as suitable antimicrobial candidates. In this study, a novel antimicrobial peptide, called dendrocin-ZM1, with a molecular weight of ~3716.48 Da, was isolated from Zataria multiflora Boiss (ZM) and purified via precipitation with ammonium sulfate and reverse-phase HPLC chromatography; it was then sequenced via Edman degradation. The in silico method was used to examine the physicochemical properties of dendrocin-ZM1. In this study, four reference strains (gram-positive and gram-negative) and one clinical vancomycin-resistant Staphylococcus aureus strain were used to survey the antimicrobial activities. Moreover, to examine cytotoxicity and hemolytic activity, a HEK-293 cell line and human red blood cells (RBCs) were used, respectively. Evaluation of the physicochemical properties of dendrocin-ZM1, as an AMP, indicated a net charge of + 7 and a hydrophobicity percentage of 54%. This peptide had an amphipathic alpha-helical conformation. It exhibited broad-spectrum antibacterial activities against the tested strains at minimum inhibitory concentrations (MICs) of 4-16 μg/mL. Besides, this peptide showed negligible hemolysis and cytotoxicity in the MIC range. It also exhibited heat stability at temperatures of 20 to 80 °C and was active in a broad pH range (from 6.0 to 10.0). Overall, the present results suggested dendrocin-ZM1 as a remarkable antimicrobial candidate.