Chemical composition, antibacterial activity and study of the interaction mechanisms of the main compounds present in the Alpinia galanga rhizomes essential oil

•Multi-target antibacterial mechanism of Galangal root essential oil was explored.•Dominant compositions included ethyl cinnamate, methyl cinnamate, n-pentadecane.•P-type ATPases and glucose-6-phosphate dehydrogenase activities were inhibited.•Spectroscopic studies and molecular docking revealed the groove binding mode. In this research, the antibacterial activity and the interaction mechanisms of the major chemical constituent present in the Alpinia galanga rhizomes essential oil (AGREO) were investigated. Ethyl cinnamate, methyl cinnamate and n-pentadecane were the major components of AGREO. The antibacterial mechanism of AGREO on Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) was evaluated and the results proved that the potent antibacterial activity of AGREO was due to higher passive permeability of bacterial cell membrane, followed by crucial intracellular components efflux. Additionally, AGREO disrupted the intracellular physiological metabolism of EHEC O157, including inhibition of P-type ATPases activity and down-regulation expression of four virulence genes associated with EHEC infections. Notably, molecular docking studies suggested that ethyl cinnamate probably competed with the structural NAD(P)+ for the binding sites of glucose-6-phosphate dehydrogenase (G6PD), resulting in a decrease in G6PD activity with subsequent suppression of respiratory metabolism. The spectroscopic techniques and molecular docking studies proved that the AGREO major components were prone to bind to the minor groove of DNA.