Phenolic compounds in dietary target the regulation of gut microbiota: Role in health and disease

Mechanisms of interaction between phenolic compounds (PCs) and gut microbiota have received widespread attention. Excluding individual differences in absorption and metabolism, the bioavailability and stability of PCs depend on the composition of the gut microbiota and the short-chain fatty acid content, producing a series of enzymatic hydrolytic, splitting and reduction reactions. Meanwhile, PCs can be used as prebiotics, and alter the Firmicutes/Bacteroidetes, reduce harmful bacteria and enrich short-chain fatty acids (SCFAs)-producing bacteria, thereby protecting and regulating the intestinal barrier and immune system. In various diseases, such as metabolic disease, cardiovascular diseases, neurological diseases and cancer, PCs can reduce clinical symptoms and reverse the disease through different pathways, such as facilitating metabolic inflammation mainly through the Lipopolysaccharide (LPS)/Toll-like receptor 4/Nuclear Factor Kappa B signaling pathway. SCFAs and LPS can be also used as two major biomarkers for the interaction PCs and gut microbiota. Based on recent findings, a comprehensive review of PCs biotransformation and gut microbiota interaction mechanisms is summarized. It will provide some perspective on selecting and consuming PCs with probiotic activity.