Traditional Chinese medicines differentially modulate the gut microbiota based on their nature (Yao-Xing)

Property theory is a unique principle guiding traditional Chinese medicine (TCM) that classifies various TCMs into four natures (hot, warm, cool, and cold) to reflect their medical actions on the human body. Despite successful application for thousands of years, characterizing the nature of medical TCMs by modern physiological indicators remains a challenge.

In this study, we investigated the potential relationship between the nature of TCMs and their modulation of the gut microbiota.

We selected twelve TCMs with hot, warm, cool, or cold natures that possess antidiarrheal effects. Their aqueous extracts were orally administered to C57BL/6 mice at a clinical dose for 4 weeks. The gut microbiota was measured by 16S rRNA-based metagenomics, and the correlation between microbial composition/function and TCM nature was analyzed.

Antidiarrheal TCMs with different natures showed distinct impacts on the gut microbiota. Hot-natured TCMs had no influence on the gut microbiota, warm-natured TCMs had a moderate influence, cool-natured TCMs had a strong influence, and cold-natured TCMs substantially changed the structure of the gut microbial community. The abundance of Anaerotruncus, Tyzzerella and Ruminiclostridium steadily increased, while that of Ruminococcaceae_UCG-010, Parasutterella and Bifidobacterium continuously decreased as the herbal nature turned from cold to hot. Microbiome functional prediction for Cluster of Orthologous Groups (COG) of proteins and Kyoto Encyclopedia of Genes and Genomes (KEGG) categories showed that colder TCMs imposed a stronger influence on microbial functional repertoires. Specifically, the abundance of ABC transporters, key bacterial proteins involved in nutrient absorption and drug resistance, was gradually decreased by colder TCMs.

Our results demonstrated that the nature of TCMs could be reflected by their modulation of gut microbes. Cold TCMs may exert their antidiarrheal effects, at least partially, by modulating the gut microbiota, while hot TCMs may alleviate dysentery in other ways.