Degradation of rutin and genistein and the effect on human bacterial fecal populations of obese and non-obese

This study re-evaluates the microbial degradation of rutin and genistein, emphasizing health-related metabotypes and novel degradation and transformation products of these compounds. In silico predictions and calculations were made to determine the molecular formulae of metabolites derived from precursor molecules by methylation, sulfation, and dehydroxylation. To validate these, anaerobic, ex vivo experiments were conducted with pooled fecal samples of obese and non-obese test persons ( n = 7 per group) over 48 h, followed by 16S rRNA gene sequencing and semi-targeted, high-resolution mass spectrometry analysis. We identified 46 rutin and 23 genistein metabolites, including novel methylated and sulfated derivatives. Microbial analysis revealed that the plant compounds influenced 34 bacterial families and 83 genera. Rutin inhibited obesity-associated genera while promoting butyrate-producing bacteria in BMI >40 samples, but reduced health-associated bifidobacteria and increased enterobacteria. Both compounds stimulated Eggerthella. These findings highlight significant microbial and metabolic shifts induced by plant-derived compounds, suggesting potential health implications. • First report on a large range of degradation and transformation products. • New bacterial metabolites of rutin and genistein were tentatively identified. • Polyphenols affect human gut microbiota (obese vs. non-obese) differently. • Polyphenols are able to stimulate the growth of dysregulated bacteria. • The approach is transferable to other polyphenols and xenobiotics.