Bound polyphenols contribute to the metabolic benefits of Rosa roxburghii Tratt.-derived dietary fiber under glucose stress.

Abstract

Rosa roxburghii Tratt. (RRT) is a fruit rich in dietary fiber and polyphenols, yet the contribution of dietary fiber-associated bound polyphenols (BPs) to its health-related bioactivity remains unclear. In this study, RRT-derived dietary fiber retaining BPs was compared with structurally preserved dephenolized dietary fiber using a glucose-stressed Caenorhabditis elegans model. Phenotypic assays combined with untargeted metabolomics and transcriptomic analysis were used to evaluate the contribution of BPs to the bioactivity of RRT dietary fiber. Both dietary fiber samples alleviated glucose-induced physiological impairment, whereas BP-retaining dietary fiber consistently showed stronger effects in reducing lipid accumulation, enhancing oxidative stress resistance, improving locomotor performance, and extending lifespan. Metabolomic analysis indicated that BP-retaining dietary fiber more effectively modulated pathways related to carbohydrate metabolism and lipid-associated metabolism and redox homeostasis, with representative changes involving glucose-6-phosphate, carnitine-related metabolites, and antioxidant-associated metabolites. Transcriptomic analysis further highlighted features associated with lipid homeostasis, stress response, proteostasis, and lysosome/autophagy related processes. Integrated multi-omics analysis further supported that removal of BPs altered transcriptomic-metabolomic association patterns, suggesting that BPs contributed to the distinct molecular response induced by RRT-derived dietary fiber under glucose stress. These findings provide new insight into the functional role of fiber-bound phytochemicals and support the further development of RRT dietary fiber as a functional food ingredient with potential metabolic health-promoting value.