Polymethoxyflavones-eugenol nanoemulsion: Dual physiological and metabolomic insights into its antibacterial action on Escherichia coli

An integrated physiological and non-targeted metabolomics approach was used to construct a eugenol-based polymethoxyflavones nanoemulsion delivery system and examine its increased antibacterial activity on E. coli . Compared with pure eugenol nanoemulsion (EG, MIC: 640 μg/mL), the polymethoxyflavones-eugenol nanoemulsion (EGP) exhibited significantly enhanced antimicrobial activity (MIC: 320 μg/mL). EGP treatment disrupted the integrity of E. coli cell membranes and walls, increased cell permeability. Non-targeted metabolomics analysis (compared with CK) revealed 685 upregulated and 642 downregulated differentially accumulating metabolites, lysine and glutamine are reduced in E. coli , and glutaric acid, aminoadipic acid, and D-lactic acid are increased. Pathway enrichment analysis showed that amino acid metabolism and energy metabolism were significantly disturbed by TCA cycle disruption. EGP exhibits superior antimicrobial efficacy against E. coli through a multi-targeted mechanism involving cell membrane disruption and metabolic pathway interference. This study provides valuable insights into the development of natural antimicrobial nanoemulsion as potential alternatives to synthetic preservatives for food safety applications.