Fish as the lesser-known counterpart to mammalian models to explore the biofunctionality of polyphenols

Dietary polyphenols improve gut health either through their direct effects on the intestinal barrier and antioxidant and immune systems of the host or through the action of metabolites produced by the microbiota. We have focused on phenolic acids like gallic acid and curcumin, stilbenes like resveratrol, and flavonoids such as quercetin, daidzein, and anthocyanins that can chelate metals and scavenge free radicals to prevent or treat intestinal inflammation and brain disorders. Although polyphenols undergo both phase I and II metabolisms, only a tiny fraction of the catabolites is bioavailable. The gut microbiota catabolizes these compounds to produce beneficial metabolites for the host.Fish can be suitable models for obtaining in-depth knowledge about the absorption and metabolism of polyphenols, and their breakdown by the gut microbiota. Gathering such knowledge along with their effects on the immune system could reveal the effectiveness of bioactive compounds like polyphenols in tackling intestine and brain disorders.