Chlorogenic acid exerts antibacterial effects by affecting lipid metabolism and scavenging ROS in Streptococcus pyogenes.

Chlorogenic acid (CGA), one of the most abundant polyphenols in the human diet, exhibits many biological properties, including antibacterial properties. Numerous studies have investigated the antibacterial effects of CGA, however, the molecular mechanisms governing its effects against Streptococcus pyogenes have not been fully elucidated. Streptococcus pyogenes is a Gram-positive pathogen that causes a wide range of human infections and postinfectious immune-mediated disorders. In this study, we used an isobaric tagging for relative and absolute quantitation (iTRAQ)-based proteomic technique to investigate the underlying mode of action of CGA against S. pyogenes. KEGG and GO analyses indicated that CGA affected the expression of protein alterations involved in multiple pathways, downregulating the expression of ribosomal proteins, and upregulating the expression of proteins associated with fatty acid metabolism, pyruvate metabolism, and propanoate metabolism, while activating the expression of oxidation-reduction-related proteins. Moreover, further cell-based experiments verified that CGA scavenges intracellular ROS in S. pyogenes. These results suggest that CGA may exert its antibacterial action through several actions, such as downregulating ribosomal subunits, affecting lipid metabolism, and scavenging intracellular ROS. The results of this study may help to elucidate the molecular mechanisms by which CGA combats pathogens.