Mastoparan-S from Sphodromantis viridis exhibits antimicrobial activity by disrupting bacterial membranes.

The increasing prevalence of antimicrobial resistance underscores the urgent need for alternative treatments. Antimicrobial peptides (AMPs) are considered viable substitutes for conventional antibiotics due to their broad-spectrum activity and unique mechanisms of action. AMPs are an integral component of the innate immune system in invertebrates. Mastoparan-S, a 14-amino acid AMP originally identified in the praying mantis Sphodromantis viridis reportedly exhibits antimicrobial activity against gram-positive and gram-negative bacteria, as well as fungi. In this study, the antibacterial activity and mechanism of action of chemically-synthesized mastoparan-S are evaluated against Staphylococcus aureus and Pseudomonas aeruginosa. Mastoparan-S exhibits potent antibacterial activity against S. aureus and P. aeruginosa, without inducing cytotoxicity or hemolytic activity in RAW264.7 or HaCaT cells. Mastoparan-S effectively inhibits biofilm formation by S. aureus and P. aeruginosa. Mechanistically, mastopran-S kills bacteria by disrupting the bacterial membrane. Collectively, these findings suggest that mastoparan-S is a potential therapeutic agent for treating S. aureus and P. aeruginosa infections.