Since CAD is an essential oil compo

Since CAD is an essential oil component, it is possible that it disrupts the cell membrane, resulting in growth inhibition. Therefore, the effect of CAD on membrane integrity was assessed using diSC35, which localizes in the cytoplasmic membrane and self-quenches its own fluorescence under normal conditions [31]. Upon exposure to compounds that permeabilize the cytoplasmic membrane, and hence disrupt the membrane potential, diSC35 is released, resulting in an increase in fluorescence. Cell membranes were depolarized at the MIC level, but not sub-MIC levels, of CAD, indicating that at least one CAD antibacterial mechanism is cytoplasmic membrane disruption. A similar effect of CAD on the cytoplasmic membrane of Listeria innocua was observed at its MIC [39]. A possible mechanism of CAD’s effect on the cytoplasmic membrane could be a reduction in cellular ATP levels [40] inhibiting membrane-bound ATPase activity [41] and interfering with electron transfer, as CAD has electro-negative characteristics [42]. A previous study with other aldehydes demonstrated that their antimicrobial activity was caused by their highly electro-negative arrangement and interaction with proteins [17]. Therefore, the carbon atoms in CAD could bind to nitrogen-containing components (e.g.protein) in the cytoplasmic membrane and change the protein structure, resulting in loss of membrane integrity.