Traditional Chinese medicine in modulating gut microbiota across major disease systems: a reviewOA

Background: The human gut microbiome is an important target for disease treatment and prevention. Various microbial species within the complex ecosystem of the microbiome have been shown to play important roles in disease. Identification of bioactive materials capable of altering the abundances of these species both safely and effectively is a major goal in microbiome research. Many traditional Chinese medicines (TCMs) have been reported to affect the composition of the gut microbiome. Here, we summarize studies that have used TCMs to alter the gut microbiome and discuss the response relationship between TCMs and gut microbial species. Methods: We searched the PubMed, Web of Science, and Knowledge Network databases using the terms “traditional Chinese medicine,” “gut microbiome,” and specific system disease names (endocrine, immune, nervous, cardiovascular, and digestive). Studies were excluded if irrelevant or if the experimental procedures were unclear. Results: TCMs have been reported to affect a wide range of gut microbial taxa spanning major phyla, including Firmicutes, Bacteroidetes, Proteobacteria, Verrucomicrobiota, Actinobacteria, and Fusobacteria. In all, 54 TCMs including compounds and extracts have been tested in rodents and 30 have been examined in human trials. Almost all studies have reported positive results in regulating the gut microbiome as well as modulating corresponding phenotypes, spanning diseases of the endocrine, immune, nervous, cardiovascular, and digestive systems. Gut species, including Akkermansia, Bacteroides, Fusobacterium, Faecalibacterium, and E. coli, were found to be regulated by 19 TCMs. A network was constructed to visualize the interactions between TCMs and these taxa. Conclusion: There exists a complex and close relationship between intestinal microflora and diseases. Sufficient experimental data and studies have proved that the imbalance of intestinal microflora affects health by mediating metabolism, immune regulation, inflammation and signal transduction. Many characteristic alterations of intestinal microflora are positively correlated with diseases, so intestinal microflora has become a potential risk index and treatment target for many diseases. Many TCMs affect the relative abundances of microbial species in the gut, and therefore may be useful for modulating the gut microbiome. This review provides a reference for prioritizing candidate TCMs from the enormous repertoire of such medicines to test which specific gut microbes are targeted.