Targeted amino acid consumption and respiratory depression to study the antibacterial mechanism of linalool against Shigella sonnei

Shigella sonnei is one of the main pathogens that cause diarrhea through contaminated food and linalool derived from essential oils (EOs) is considered to have excellent antibacterial activity. Therefore, this study aimed to clarify the potential mechanism of linalool against S. sonnei using metabolomics technology. It was found that a total of 89 and 122 differential metabolites (DMs) were identified in the positive and negative ion modes, respectively. These DMs were mainly involved in glutathione metabolism, glycine, aspartic acid and glutamic acid metabolism and TCA cycle. Moreover, the protein conformation was changed according to the result of circular dichroism and the enzyme activity responsible for amino acid conversion was also inhibited under linalool stress. In particular, the activities of enzymes related to TCA cycle including CS, ICDHc, α-KGDH, SDH and MDH was reduced with linalool. In summary, these results revealed that linalool inhibited S. sonnei mainly by causing insufficient energy levels and amino acid limitation. These findings highlight the mechanism involved in the inhibition of S. sonnei by linalool, which suggests that linalool has outstanding antibacterial potential and can be developed as a promising natural preservative for controlling S. sonnei contamination in the food industry.