Effects of polyphenols on Microbial Cell-Cell Communicatios

Microbial communities developed several ways to interact and to associate with their environment. They can coordinate both microbial interactions and association with higher organisms through specific systems of intercellular communication, often based on the expression of genes, known as quorum sensing systems (QS), taking place only when microorganisms reach a specific cell density. QS regulates a number of activities, such as bioluminescence, virulence factor expression, sporulation, biofilm formation and mating. The continuing search for novel antimicrobial and anti-pathogenic agents stimulated the investigation to discover new natural therapeutic agents that might act as nontoxic inhibitors of QS. Polyphenols are a family of about 5,000 natural molecules widely diffused in plant kingdom, as well as in some marine organisms. Most of them are capable of affecting the growth, the quorum sensing activity and the biofilm formation in several bacteria and fungi. The chapter primarily focuses on polyphenols as natural QS inhibitors, potentially useful in the treatment of microbial infections and as natural preservatives for food safety.