Antibacterial Activity of Cysteine-Derived Cationic Dipeptides

Antibiotic resistance is a growing problem, especially in the treating of life-threatening diseases like sepsis. One way to address such an issue is with the use of antimicrobial peptides, which can kill many types of bacteria by disrupting cellular targets (such as membranes) through electrostatic interaction. In this report, cysteine-derived cationic dipeptides lysine-cysteine (KC), arginine-cysteine (RC) and histidine-cysteine (HC) were used to evaluate antibacterial activity against Gram-negative and positive bacteria. The dipeptides exhibited bacterial membrane rupture capabilities under SEM observation after treatment with IC50 conditions, as well as low cytotoxicity and hemolytic activity toward normal cell lines and human red blood cells (RBCs) at IC50. Furthermore, the dipeptides significantly ameliorated Enterohaemorrhagic E. coli (EHEC)-induced lethality in Caenorhabditis elegans in a dose-dependent manner. These cysteine-derived cationic dipeptides may provide a novel alternative therapy in combating bacterial infection.