The Gut Microbial Co-Abundance Gene Groups (CAGs) Differentially Respond to the Flavor (Yao-Wei) of Chinese Materia Medica

The property theory is a unique principle instructing traditional Chinese doctors to prescribe proper medicines against diseases. As an essential part of it, the five-flavor theory catalogs various Chinese materia medicas (CMMs) into five flavors (sweet, bitter, sour, salty, and pungent) based on their taste and medical functions. Although CMM has been successfully applied in China for thousands of years, it is still a big challenge to interpret CMM flavor via modern biomarkers, further deepening its elusiveness. Herein, to identify the correlation between gut microbiota and CMM flavor, we selected 14 CMMs with different flavors to prepare their aqueous extracts, quantified the contained major chemical components, and then performed full-length 16S rRNA sequencing to analyze the gut microbiota of C57BL/6 mice administrated with CMM extracts. We found that flavones, alkaloids, and saponins were the richest components for sweet-, bitter-, and pungent-flavored CMMs, respectively. Medicines with merged flavors (bitter-pungent and sweet-pungent) displayed mixed profiles of components. According to gut microbial analysis, modulation of CMMs belonging to the same flavor on the taxonomic classification was inconsistent to an extent, while the functional sets of gut microbiota, co-abundance gene groups (CAGs), strongly and differentially responded to distinct flavors. Moreover, these correlations were in line with their pharmacological actions. Therefore, the gut microbial functional sets (CAGs) could act as the possible indicator to reflect CMM flavor, rather than the composition of microbial community.