Antimicrobial effect and mode of action of chlorogenic acid on Staphylococcus aureus

Natural products have been developed as an alternative source of novel antibacterials in combating food-borne pathogens such as Staphylococcus aureus (S. aureus), Salmonella, Listeria monocytogenes. The aims of this study were to investigate the antimicrobial effect of chlorogenic acid (CA) on S. aureus and to elucidate its mechanism of action. Minimum inhibitory concentrations of CA were determined using the agar dilution method. Intracellular pH (pHin), membrane potential, intracellular and extracellular ATP concentrations, and the release of cell constituents were measured to elucidate antibacterial mechanism. Morphological changes induced by CA were examined by electron microscopy. CA induced a decrease in the intracellular ATP concentrations, but no proportional increase in the extracellular ATP. And the release of cell constituents increased significantly when treated with CA. A reduction in pHin and cell membrane hyperpolarization were observed in S. aureus after CA treatment. Electron microscopic observations showed that the cell membrane of S. aureus was damaged by CA. It is concluded that CA inhibited the proliferation of S. aureus and destroyed the permeability of the cell membrane. The findings indicated that CA has the potential to be developed as an alternative to control S. aureus and the diseases associated with this microorganism.