Metabolomic analyses reveal the antibacterial properties of a novel antimicrobial peptide MOp3 from Moringa oleifera seeds against Staphylococcus aureus and its application in the infecting pasteurized milk

The peptide MOp3 from Moringa oleifera seeds has been reported to have good antimicrobial activity against Staphylococcus aureus, but its specific antimicrobial effect is still unclear. Therefore, the present study aimed to investigate the antibacterial properties of MOp3 against S. aureus in terms of membrane damage, intracellular key enzyme activities, cell apoptosis induction, and metabolite changes, and evaluate its antibacterial ability in pasteurized milk. The results showed that MOp3 caused irreversible membrane damage to S. aureus cells by increasing the membrane permeability and decreasing the activity of intracellular AKP, LDH, and ATPase. Moreover, ROS accumulation, DNA fragmentation, and nuclear rupture in the S. aureus cells treated with MOp3 induced cell apoptosis. The metabolomics analysis revealed that 46 different metabolites were involved in peptidoglycan synthesis, amino acid metabolism, glycerophospholipid metabolism, nucleotide metabolism, and energy metabolism, that can affect cell wall biosynthesis, cell membrane structure, and genetic material expression. Besides, MOp3 inhibited the growth of S. aureus in the infecting pasteurized milk which storaged at 25 °C and 4 °C for 7 days. Overall, these findings provided deeper insights into antibacterial properties of MOp3 against S. aureus and its application in food preservation.