Daikenchuto modulates gut microbial metabolism to mitigate irinotecan-induced enterotoxicity

Gut microbiota metabolic remodeling is a pivotal determinant in irinotecan-induced enterotoxicity and epithelial damage, although the underlying mechanisms remain unclear. Herein, we discovered that Daikenchuto (DKT), a traditional Chinese prescription for intestinal disorders, alleviated irinotecan-induced enterotoxicity without compromising its anti-tumor efficacy by improving weight loss, diarrhea, intestinal inflammation, and barrier damage, and these effects were partially dependent on gut microbiota. DKT significantly restored microbial tryptophan metabolism in irinotecan-treated rats, which was characterized by the enrichment of Limosilactobacillus reuteri, and elevated levels of indole-3-ethanol (IE) and indole-3-propionic acid (IPA). Multi-omics analysis further revealed a positive correlation between L. reuteri and IE and IPA. Consistent with this, DKT promoted L. reuteri proliferation, leading to the conversion of tryptophan to IE and IPA, which improved epithelial barrier damage in the irinotecan-treated Caco-2 cells. In addition, DKT suppressed the growth of Loop 1 {beta}-glucuronidase ({beta}-GUS)-producing bacteria, such as Escherichia coli. Furthermore, the main constituents of DKT selectively inhibited Loop 1 {beta}-GUS activity independent of the gut microbiota, which reduced the intra-luminal level of 7-ethyl-10-hydroxycamptothecin, the toxic metabolite of irinotecan. Taken together, this study reveals a dual gut microbiota-driven mechanism by which DKT mitigates irinotecan-induced enterotoxicity, which provides a promising strategy for managing chemotherapy-related enterotoxicity.