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DOI: 10.1055/s-0037-1608574
Combining LC-MS metabolomics and next generation sequencing to study the interactions between herbal medicines and human gut bacteria in-vitro
Publication History
Publication Date:
24 October 2017 (online)
The microbial community that populates the human distal gut has a strong impact on human health and enormous metabolic capacity. Therefore, many constituents of herbal medicines that remain unabsorbed in the upper intestinal tract are available for metabolization by human gut microbiota. This might lead to the formation of potentially bioavailable and bioactive metabolites, an aspect that was often not considered in the past when searching for active principles of herbal medicines.
We have established an interdisciplinary platform that allows investigating the metabolization of herbal medicines by human gut bacteria, as well as their influence on gut microbial community composition. Herbal preparations were incubated with human fecal suspension under anoxic conditions. After 0.5, 4 and 24h, samples were taken and subjected to LC-HRMS and 16 s RNA sequencing analysis.
This approach has been applied to three approved herbal medicinal products: standardized willow bark extract, hawthorn leaves and flowers extract, and a fixed combination-preparation consisting of 9 herbal extracts.
In all cases, microbial degradation was found to be strongly dependent on compound class and extract concentration. Constituents like caffeoyl quinic acids, catechins, procyanidins and flavonoid-O-glycosides were usually metabolized very fast. Metabolization could also be shown for C-glycosylflavones and triterpene glycosides. Assignment of newly formed metabolites allowed the construction of putative degradation patwhays for many degraded compounds. Interestingly, the use of higher extract concentrations usually retarded the observed metabolic reactions, indicating that too high concentrations of certain compounds might inhibit microbial metabolic enzymes.
16S rRNA gene sequencing revealed significant changes in microbial community composition upon extract addition, and allowed the assignment of certain microbial taxa that are potentially involved in some of the observed metabolic reactions.
We thank Steigerwald Arzneimittelwerk GmbH, Bayer Consumer Health and Dr. Willmar Schwabe GmbH & Co. KG for financial support.