Document Type
Oral Presentation
Location
Oxford Conference Center
Event Website
https://oxfordicsb.org/
Start Date
22-4-2026 10:30 AM
End Date
22-4-2026 10:50 AM
Description
Background: Recent evidence suggests that natural products can modulate microbiome composition, offering health benefits. This study evaluates the effects of STW 5 (Iberogast) on microbiota in functional dyspepsia (FD) and Irritable Bowel Syndrome (IBS) through a comparison of in vitro and in vivo data. Methods: A comprehensive literature review was conducted using PubMed and other scientific databases to collate data on STW 5's impact on the gut microbiome at phyla and genera levels. Results: In vitro studies demonstrated an increase in Enterococcus and a decrease in Clostridium and Bacteroides. Further in vitro research confirmed an increase in Firmicutes and a reduction in Bacteroidetes, with a decrease of Blautia and Proteobacteria. Unpublished data of the authors indicated increased Bifidobacterium and Blautia, with no change in Lactobacillus. In vivo studies in healthy Wistar rats reported minor increases in the phyla Firmicutes and Bacteroidetes, and a significant decrease in Actinobacteria. Genus-level changes included increases in Bacteroides, Bifidobacterium, and Prevotella, and a significant rise in Methanobrevibacter. In the UC model, Lactobacillus, Blautia, and Bifidobacterium increased, while Proteobacteria and Enterococcus decreased. In the in vivo FD model, significant increases were observed for Enterococcus, Lactobacillus, Blautia, and Bacteroidetes. Actinobacteria decreased, with elevated Bifidobacterium compared to FD control, but lower than in healthy controls. Discussion: The different responses of some genera like Blautia and Enterococcus to STW 5 in in vitro models as compared to in vivo models highlight the complexity of the interactions of the microbiota with STW 5. The limitations of in vitro models due to the absence of host factors underscore the advantages of using diverse research methodologies to identify microbial changes relevant to human health. Our results demonstrate such an approach, revealing consistent microbial shifts across the models. In particular, the upregulation of Bifidobacterium, with the downregulation of Actinobacteria and Proteobacteria, highlight the potential of STW 5 for beneficial gut microbiome modulation, underscoring its multi-target mechanism of action. Conclusion: This study demonstrates the significant impact of STW 5 on gut microbiota across in vitro and in vivo models. The presence of contradictory results underscores the need for a multifaceted approach to accurately characterize the intricate interactions between natural products and the gut microbiome. The identification of consistent microbial shifts associated with STW 5 provides mechanistic insight contributing to its clinically-proven health benefits. Further research, will be valuable to confirm the translational relevance of these findings.
Recommended Citation
Kelber, Olaf, "In vitro vs. in vivo studies on the interaction of natural products with the gut microbiota: The example of STW 5" (2026). Oxford ICSB. 19.
https://egrove.olemiss.edu/icsb/2026_ICSB/Schedule/19
Publication Date
April 2026
Accessibility Status
Screen reader accessible, Searchable text
Included in
In vitro vs. in vivo studies on the interaction of natural products with the gut microbiota: The example of STW 5
Oxford Conference Center
Background: Recent evidence suggests that natural products can modulate microbiome composition, offering health benefits. This study evaluates the effects of STW 5 (Iberogast) on microbiota in functional dyspepsia (FD) and Irritable Bowel Syndrome (IBS) through a comparison of in vitro and in vivo data. Methods: A comprehensive literature review was conducted using PubMed and other scientific databases to collate data on STW 5's impact on the gut microbiome at phyla and genera levels. Results: In vitro studies demonstrated an increase in Enterococcus and a decrease in Clostridium and Bacteroides. Further in vitro research confirmed an increase in Firmicutes and a reduction in Bacteroidetes, with a decrease of Blautia and Proteobacteria. Unpublished data of the authors indicated increased Bifidobacterium and Blautia, with no change in Lactobacillus. In vivo studies in healthy Wistar rats reported minor increases in the phyla Firmicutes and Bacteroidetes, and a significant decrease in Actinobacteria. Genus-level changes included increases in Bacteroides, Bifidobacterium, and Prevotella, and a significant rise in Methanobrevibacter. In the UC model, Lactobacillus, Blautia, and Bifidobacterium increased, while Proteobacteria and Enterococcus decreased. In the in vivo FD model, significant increases were observed for Enterococcus, Lactobacillus, Blautia, and Bacteroidetes. Actinobacteria decreased, with elevated Bifidobacterium compared to FD control, but lower than in healthy controls. Discussion: The different responses of some genera like Blautia and Enterococcus to STW 5 in in vitro models as compared to in vivo models highlight the complexity of the interactions of the microbiota with STW 5. The limitations of in vitro models due to the absence of host factors underscore the advantages of using diverse research methodologies to identify microbial changes relevant to human health. Our results demonstrate such an approach, revealing consistent microbial shifts across the models. In particular, the upregulation of Bifidobacterium, with the downregulation of Actinobacteria and Proteobacteria, highlight the potential of STW 5 for beneficial gut microbiome modulation, underscoring its multi-target mechanism of action. Conclusion: This study demonstrates the significant impact of STW 5 on gut microbiota across in vitro and in vivo models. The presence of contradictory results underscores the need for a multifaceted approach to accurately characterize the intricate interactions between natural products and the gut microbiome. The identification of consistent microbial shifts associated with STW 5 provides mechanistic insight contributing to its clinically-proven health benefits. Further research, will be valuable to confirm the translational relevance of these findings.
https://egrove.olemiss.edu/icsb/2026_ICSB/Schedule/19
Comments
Olaf Kelber is research scientist at the Phytomedicines Supply and development Center of Bayer Consumer Health in Darmstadt, Germany. He is biologist with specialization in toxicology and has a master´s degree in pharmaceutical medicine. He was leading the pharmacological laboratory of the site, before he took over the scientific project management for the re-registration of a broad portfolio of herbal medicinal products, building a broad spectrum of academic collaborations in the field. He then took over the leadership of the clinical research and medical information team of the site, before changing to his present functions. He was leading diverse projects in the fields of pharmacovigilance, toxicology, pharmacology and clinics of natural health products and is author or co-author of more than 70 publications in scientific journals and 700 contributions to scientific congresses. He is member of the Q3C working group of ICH, Geneva, the scientific working group of Kooperation Phytopharmaka, Bonn and of the board of the German Society for Phytotherapy, as well as secretary of the Society of Medicinal Plant and Natural Product Research (GA).
This contribution is dedicated to Prof. Mohamed T. Khayyal, Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt, who passed away on 3 September 2025.