Modulation of human gut microbiota by yarrow extract and phenolic mixture in the TIM-2 in vitro model of the colon

Aim: This study aimed to evaluate the effects of yarrow extract and a phenolic mixture comprising apigenin, caffeic, and chlorogenic acids on the gut microbiota using the TIM-2 in vitro system.Methods and results: The TIM-2 units were inoculated with fecal samples from healthy individuals and supplemented with test substrates for 72 hours. Microbiota composition was assessed by V3-V4 16S rRNA gene sequencing, while organic acids production was evaluated by GC-MS. The yarrow extract stimulated probiotic bacteria Lactiplantibacillus, and other abundant and symbiotic gut inhabitants including Coriobacteriaceae, Eggerthellaceae, Christensenellaceae, Butyricicoccaceae, and the Eubacterium coprostanoligenes group. The phenolic mixture exerted milder effects on gut microbiota by enhancing the growth of Eggerthellaceae and Collinsella. Looking at the microbial activity, the production of SCFAs, specifically acetic and propionic acids was increased in the yarrow group.Conclusion: The obtained results highlight the importance of yarrow phenolics in maintaining microbiota balance. The yarrow extract and specific phenolics may modulate the gut microbiota by promoting the growth of SCFA producers and stimulating SCFA synthesis.