There are multiple pathways for communication of gut microbes with human organs. Trimethylamine N-oxide (TMAO) is generated via a metaorganismal pathway, which begins with the conversion of dietary phosphatidyl choline into trimethylamine in the gut of microbes, followed by liver oxidation of TMAO by flavin monooxygenases in the host. The gut-liver axis that links the liver metabolism and the gut microbiota plays an important role in the mechanisms of liver diseases. Translocated lipopolysaccharide (LPS) enters the liver through hepatic portal vein and causes damage to the liver function. Changes in the gut microbiota can affect the function of central nervous system through multiple signaling pathways, including the hypothalamus-pituitary-adrenal axis, immune regulation, serotonin metabolism, and production of neuroactive compounds.

Abbreviations: ACTH, adrenocorticotropic hormone; CRH, corticotropin-releasing hormone; GABA, gamma-aminobutyric acid; HPA, hypothalamic–pituitary–adrenal; LPS, lipopolysaccharide; SCFAs, short-chain fatty acids; 5-HT, serotonin; TMA, trimethylamine; TMAO, trimethylamine oxide.

There are trillions and trillions of microorganisms in the human gut, and these microorganisms and their metabolites are closely related to human health. Recent studies have found that the abundance of Akkermansia muciniphila is decreased in many diseases. Supplementation of A. muciniphila is used to treat many diseases, suggesting it as a probiotic. Herbal medicines are considered as valuable asset of traditional Chinese medicine. Recent studies have revealed traditional Chinese medicine as a potential prebiotic agent for the treatment of many diseases. Hence, in this review, we aimed to provide a plausible mechanistic basis for the interactions between herbal medicines and A. muciniphila, and therapeutic benefits on this interaction in various illnesses.