Abstract
Plant polyphenols are a class of chemically diverse molecules that contribute, among many other health benefits, to sustain an enhanced host gut microecological niche. It is thought that the modulation of the gut microbiota by these metabolites is a crucial process that contributes to maintain gut homeostasis. Polyphenols are known to shift the gut microbiota composition inhibiting opportunistic pathogens and exerting a prebiotic-like effect on beneficial gut microbes, being Lactobacillus spp. one of the enriched taxa. In this chapter we describe how different polyphenol classes target the relative abundance and growth of Lactobacillus spp. Although lactobacilli can positively respond to polyphenols, mechanistic insights into how polyphenols stimulate these gut microbes is generally limited. However in recent years it has been revealed that some polyphenols can modulate molecular functions implicated in the adaptation of lactobacilli to the gut environment. In addition, some polyphenols can modulate the expression of molecular functions that are engaged in the crosstalk between lactobacilli and intestinal host cells. These developments can provide molecular-based scientific support for polyphenol-mediated improvement of effector capacities of Lactobacillus associated with beneficial effects on host-physiology.