Study on the antibacterial effect of the new anti-biofilm inhibitor ICAC on Escherichia coli

The rise of bacteria antibiotics resistance has bacome increasingly severe, and the development of natural compounds with antibacterial activity represents a promising approach to combat this issue. The efficacy and mechanisms of the plant-derived phenolic compound isochlorogenic acid C (ICAC) as an antibacterial and antibiofilm agent against <i>E. coli</i> were investigated. The study utilized a comprehensive approach encompassing crystal violet staining, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), the ruthenium red method, semi-solid agar motility assays, and quantitative real-time PCR (qRT-PCR) to elucidate the inhibitory effects and their underlying mechanisms. Results revealed that ICAC exhibited significant antibacterial and antibiofilm activity against <i>E. coli</i>. The results demonstrated that ICAC could inhibit the biofilm formation of <i>E. coli</i>, reduce the biomass of preformed biofilms, and decrease the production of extracellular polysaccharides (EPS) and extracellular proteins, as well as bacterial motility. Moreover, qRT-PCR results showed that ICAC downregulated genes associated with c-di-GMP synthesis while upregulating those involves in c-di-GMP degradation, thereby inhibiting biofilm formation and bacterial motility. In summary, ICAC shows potential as an effective anti-c-di-GMP agent and a novel antibacterial candidate for the treatment of E. coli infections.