Inhibitory activity of bioactive compounds on quorum sensing in foodborne bacteria

Abstract

Bacteria coordinate gene expression in a cell-density-dependent manner through signaling molecules, also known as autoinducers, in a process called quorum sensing (QS). QS synchronizes the production of virulence factors including toxins and proteases, potentially impacting the microbiological quality and safety of foods. Interference with the QS system, known as quorum quenching (QQ), can offer alternatives to traditional antimicrobial use providing a new anti-virulence strategy. The potential of plant secondary metabolites to inhibit QS is of particular interest due to the dynamic interactions between plants and microorganisms. However, the specific mechanisms involved in QS inhibition remain poorly understood. This project aims to assess the inhibitory potential of different classes of bioactive compounds and their combinations on bacteria relevant to food safety and human health, elucidating possible mechanisms of action and practical applications. Initially, through a systematic review of the literature, compounds with antimicrobial and QS inhibitory potential will be selected. Upon confirmation of the inhibitory potential on foodborne bacteria, compounds with the best activity will be nanoencapsulated and tested for comparison of antimicrobial and QQ activity in this new condition. The same compounds will also be evaluated for the specificity of QS inhibition, identifying the mechanisms of action through microscale thermophoresis (MST) assays and qRT-PCR gene expression analysis in QS-associated genes. A study of cytotoxicity and efficacy in vitro and in vivo using Caenorhabditis elegans will be conducted. Finally, the application of nanoencapsulated compounds as edible coatings and in food packaging films will be investigated. The project aims to enhance the understanding of bacterial inhibition processes by bioactive compounds and advance their application in the food industry. (AU)