Ginsenoside Rh4 Suppresses Colorectal Tumorigenesis Through the Modulation of Gut Microbiota-Mediated Bile Acid Metabolism

Background: Gut microbiota dysbiosis is emerging as a key factor in the pathogenesis of colorectal cancer (CRC). Ginsenoside Rh4 (Rh4) is an active compound isolated from ginseng with beneficial effects in modulating intestinal inflammation and gut microbiota dysbiosis, but how Rh4 regulates the gut microbiota to alleviate CRC remains underexplored.Methods: We used the AOM/DSS model and employed transcriptomics, genomic and metabolomic techniques to investigate the inhibitory effect of Rh4 on colorectal tumorigenesis. Furthermore, we adopted a systematic approach to explore the interplay between Rh4 and the gut microbiota in preventing CRC, utilizing experiments involving antibiotic treatment and fecal microbiota transplantation (FMT). Finally, we elucidated the pivotal role of key functional bacteria and metabolites regulated by Rh4 in colorectal tumorigenesis.Findings: Our results demonstrated that Rh4 significantly suppressed colorectal tumorigenesis and facilitated the restoration of intestinal barrier function in a gut microbiota-dependent manner. Rh4 regulated gut microbiota dysbiosis by modulating the abundance of beneficial bacteria, specifically Akkermansia muciniphila (A. muciniphila). Indeed, Rh4 additionally modulated the metabolism of bile acids mediated by the gut microbiota, with a particular emphasis on elevating the beneficial secondary bile acid, ursodeoxycholic acid (UDCA). More importantly, A. muciniphila promoted the synthesis of UDCA by elevating the activity of 7α-hydroxysteroid dehydrogenase (7α-HSDH), which directly regulated the FXR-TLR4-NF-κB signaling pathway and inhibited the development of colon tumors.Interpretation: Our research elucidates that Rh4 exerts its inhibitory effect on colorectal tumorigenesis by modulating gut microbiota-mediated UDCA and suggests that Rh4 may serve as a potential modulator of gut microbiota for the prevention and treatment of CRC.Funding: This work was financially supported by the National Key Research and Development Program of China (Grant Nos.: 2021YFC2103900) and the National Natural Science Foundation of China (Grant Nos.: 22278335 and 21978236), and the Natural Science Basic Research Program of Shaanxi, China (Grant No.: 2023-JC-JQ-17).Declaration of Interest: Xue Bai, Zhiguang Duan, Jianjun Deng, Zhuo Zhang, Rongzhan Fu, Chenhui Zhu, and Daidi Fan declare that they have no conflict of interest or financial conflicts to disclose.Ethical Approval: The animal experiments were conducted with the approval of the Laboratory Animal Management and Ethics Committee of the Northwest University (Approval No.: NWU-AWC-20220903M).