<i>Triphala</i> extract reshapes microbial and host proteomes in an obese descending colon model

The descending colon is a unique niche dominated by protein fermentation, bile acid conversion, and mucosal turnover, making it key for dietary intervention studies. Using a dynamic in vitro human descending colon model inoculated with obese-donor microbiota, we examined the temporal effects of Triphala extract (TPE) supplementation. High-resolution metaproteomics profiled both microbial and host proteomes across baseline, 4 weeks of TPE supplementation, and 2 weeks of withdrawal in a dynamic in vitro human descending colon model. Principal component and volcano plots showed robust remodeling: microbes shifted toward amino acid/nucleotide metabolism and hosts toward transcriptional and signaling regulation. Supplementation transiently redirected microbes to carbohydrate metabolism and reduced stress proteins, while hosts increased mitochondrial and lipid metabolism, indicating greater energy use. Withdrawal triggered rebound effects, with microbial stress proteins and suppressed host regulators reflecting ecological memory. Correlation networks revealed cooperative microbe–host metabolic links and antagonistic ties between microbial stress pathways and host structural proteins. These findings show that TPE alleviates proteolysis, promotes saccharolysis, and reshapes host transcriptional networks. Integrating microbial and host proteomes, this study reveals how phytochemicals influence distal gut ecology and suggests TPE may enhance epithelial resilience and metabolic balance in obesity.