Label-free quantitative proteomic analysis of the inhibitory activities of juglone against translation and energy metabolism in Escherichia coli

Abstract

Plant-derived antimicrobial agents have received increasing attention owing to their potential to control pathogens and excellent efficacy despite the growing prevalence of antibiotic resistance. However, the antibacterial mechanism of juglone, a traditional medicine used to cure skin infections, is still unclear. Therefore, in this study, in order to elucidate the mechanisms underlying the antibacterial activity of juglone, label-free quantitative proteomic technology was applied for analysis of the 417 proteins that were differentially expressed in Escherichia coli after treatment with juglone at one-half of the minimum inhibitory concentration. Gene ontology enrichment analysis of differentially expressed proteins suggested that juglone effectively repressed the expression of dehydrogenase and cytochrome oxidase, indicating that energy generation was blocked. Additionally, juglone induced RNA formation and ribosome assembly, resulting in inhibition of translation. This is the first study to adopt a proteomic approach to investigate the antibacterial mechanism of action of juglone against E. coli.