Isolation, identification and characterization of a novel antimicrobial peptide from Moringa oleifera seeds based on affinity adsorption

This study aimed to characterize a novel antimicrobial peptide (AMP) obtained from Moringa oleifera seed protein hydrolysates. Cell membrane chromatography and live bacteria adsorption were combined into a single step to efficiently isolate the active fraction of the AMP. Five peptides were identified by LC-MS/MS, among which the MCNDCGA peptide (termed MOp3) showed the greatest inhibitory effect against Staphylococcus aureus [minimum inhibitory concentration (MIC): 2 mg/mL]. MOp3 was identified as a hydrophobic anionic AMP rich in ss-sheet structures with negligible hemolytic activity at 2.0 x MIC. MOp3 had good tolerance to salt solutions at 5 % and pH range 6.0-8.0, but was sensitive to high temperatures (>100 degrees C) and acid protease. Microscopic observation further revealed that MOp3 induced irreversible damage onto the cell membrane of S. aureus and interacted with dihydrofolate reductase and DNA gyrase by hydrogen bonding and hydrophobic interaction. These findings highlight the potential application of a new antimicrobial agent against S. aureus in the food industry.

Automated summary

This study aimed to isolate and characterize a new antimicrobial peptide (AMP) from Moringa oleifera seed protein hydrolysates. Through combining cell membrane chromatography and live bacteria adsorption, the active fraction of the AMP was efficiently isolated. The identified peptide MCNDCGA (termed MOp3) showed strong inhibitory effect against Staphylococcus aureus, making it a potential antimicrobial agent in the food industry.