Epigallocatechin gallate protects mice from Salmonella enterica ser. Typhimurium infection by modulating bacterial virulence through quorum sensing inhibition

<i>Salmonella enterica</i> ser. Typhimurium is a common pathogen that poses a considerable public health threat, contributing to severe gastrointestinal diseases and widespread foodborne illnesses. The virulence of <i>S.</i> Typhimurium is regulated by quorum sensing (QS) and the type III secretion system (T3SS). This study investigated the inhibitory effects and anti-QS activity of epigallocatechin gallate (EGCG), which is a bioactive ingredient found in green tea, on the virulence of <i>S.</i> Typhimurium. <i>In vitro</i> bacterial experiments demonstrated that EGCG inhibited the production of autoinducers, biofilm formation, and flagellar activity by downregulating the expression of AI-1, AI-2, <i>Salmonella</i> pathogenicity islands (SPI)-1, SPI-2, and genes related to flagella, fimbriae, and curli fibers. In a mouse model of <i>S.</i> Typhimurium-induced enteritis, EGCG considerably reduced intestinal colonization by <i>S</i>. Typhimurium and alleviated intestinal damage. In conclusion, EGCG protects the intestines of mice infected with <i>S.</i> Typhimurium by inhibiting QS-induced virulence gene expression, demonstrating its potential as a therapeutic agent for controlling <i>S.</i> Typhimurium infections.