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DOI: 10.1055/s-0037-1608399
Metabolization of the herbal combination STW-5 by human gut microbiota in vitro
Publication History
Publication Date:
24 October 2017 (online)
The herbal medicinal product STW-5 is a fixed combination of 9 different plant extracts that was shown to be effective in functional gastrointestinal diseases like functional dyspepsia and irritable bowel syndrome. Many STW-5 constituents are polar compounds. Due to the low oral bioavailability of such substances, they potentially reach the distal gut where they can interact with the local microbial community. Human gut microbiota are known to possess enormous metabolic capacity. This can lead to the production of new, potentially bioactive metabolites from plant constituents. The aim of this study was to investigate how gut bacteria metabolize STW-5 constituents, and whether incubation with STW-5 has an influence on gut microbial communities.
Lyophilized STW-5 dissolved in buffer (0.45 and 2.25 mg/ml) was incubated with human fecal suspension (HFS) under anoxic conditions. Samples were taken 0.5, 4 and 24h after STW-5 or vehicle addition, and subjected to LC-DAD-HRMS analysis to detect changes in the extract's metabolic profile, and to next generation sequencing analysis (Illumina, MiSeq) to detect changes in the microbiome.
Results revealed dramatic modifications of the metabolic profile of STW-5 incubated with HFS. Major phenolic constituents like rosmarinic acid, and liquiritin- and eriodictyol glycosides were metabolized so fast that they were not detectable anymore after 0.5h of incubation. Instead, their putative metabolites dihydrocaffeic acid, liquiritin and eriodictyol were found to be enhanced after 0.5h, but further degraded at later time points. Triterpene glycosides, another major group of STW-5 constituents, remained stable within the first 30 min but were found to be degraded subsequently.
These fast metabolic reactions were accompanied by rapid and dramatic changes in microbiome community composition. Notably, in particular Enterococcus species were found to be massively enhanced upon STW-5 addition.
We thank Steigerwald Arzneimittelwerk GmbH, Bayer Consumer Health (Darmstadt, Germany) for financial support.