Antimicrobial mechanism of clove oil on Listeria monocytogenes

Although clove oil is widely used in food preservation, very little is known about its possible antibacterial mechanism. In order to reveal its antibacterial mechanism, the inhibitory effect of clove oil on Listeria monocytogenes and its effect on cell membrane, respiratory metabolism, and its interaction with DNA were investigated, respectively. The results showed the treatment of clove oil can cause the leakage of three biological macromolecules (protein, ATP and DNA) and the reduction of two intracellular enzymes (β-galactosidase and AKP) activities, indicating that clove oil has an effect on cell membrane permeability. The inhibition rate and superposition rate test confirmed that the pathway of clove oil affecting the respiratory metabolism of Listeria monocytogenes is TCA pathway. The treatment of clove oil can reduce the activity of three key enzymes (isocitrate dehydrogenase, citrate synthase and α-ketoglutarate dehydrogenase) in TCA pathway, and affect the content of metabolites in the pathway. The results of ultraviolet absorption spectroscopy showed that eugenol, the main component of clove oil, can change the structure of DNA via the formation of eugenol-DNA chimera.