Comparative genomics and functional characterization of 11 newly isolated non-equol-producing Adlercreutzia strains with anti-inflammatory properties

Adlercreutzia, a prevalent genus in the human gut microbiota, gains growing interest due to the potential beneficial effects on human health, particularly in the context of metabolic and inflammatory diseases. Previous work showed the A. equolifaciens type strain exhibits anti-inflammatory properties, but whether this effect is strain-specific or linked to equol production remained unclear. In this study, we isolated 11 novel Adlercreutzia strains from healthy European volunteers. Whole-genome sequencing classified most isolates closely related to A. rubneri or A. equolifaciens species. Phenotypic characterization revealed all isolates are obligate anaerobes, asaccharolytic, non-equol producers and exhibit strain-dependent tolerance to oxygen and bile salts, opening up possibilities for therapeutic options. Functional assays demonstrated that all strains exert significant anti-inflammatory effects in vitro by downregulating NF-κB activation in human intestinal epithelial and liver cells. These findings reveal potent anti-inflammatory activity independent of equol production, positioning these novel, well-characterized Adlercreutzia strains as promising candidates for microbiome-based therapies targeting metabolic diseases.