Figure 5.

Polyphenol's mode of actions shaping the gut microbiota. (Poly)phenols reaching the gut can exert an important antimicrobial pressure (red lines) on several members of the microbiota. They can also be transformed by a vast and diverse array of microbial (poly)phenol-associated enzymes (PAZymes). Bacteria possessing the required PAZymes can improve their fitness by the metabolic utilization of a given polyphenol and thrive within the (poly)phenol-enriched gut environment (green arrow). This leads to the production of primary bioactive metabolites (M¹) that can be involved in trophic interactions and further be metabolized by other microorganisms possessing the appropriated PAZymes, releasing secondary metabolites (M²), and so on. PAZymes can degrade (poly)phenols without conferring any direct advantage to the bacteria (light blue arrow) in a detoxifying-like effect. The residual product can become a primary bioactive metabolite (M¹) and enter the trophic network. Other bacteria may not possess PAZymes required for the degradation of a specific (poly)phenolic compound but can instead resist its antimicrobial effect (dark blue arrow). This confers those strains an advantage to take over sensitive competitors. First and second transformers and resistant bacteria, as well as (poly)phenol metabolites (M¹ and M²), can modulate the intestinal ecological niche and induce local and systemic beneficial effects by interacting with the host (gray arrows). In turn, those metabolic changes can also modulate the intestinal ecological niche (orange arrow) in a crosstalk fashion. (Poly)phenol metabolites (M¹ and M²) can also induce an antimicrobial effect (red lines). The yellowish area highlights (poly)phenol prebiotic path process, while the red dashed square identifies the antimicrobial effect of (poly)phenol, both defining the duplibiotic effect.