Native dietary fiber-bound phenolics complex from Lentinula edodes alleviate colitis through gut microbiota and...

Dietary fiber-bound phenolics are naturally occurring complexes in foods, yet the functional significance of preserving their native dietary fiber-phenolic assembly remains poorly understood. In this study, using a removal-reconstitution strategy, we compared native soluble dietary fiber-bound phenolics (SDF-BP) from Lentinula edodes with its bound phenolic-removed fraction (SDF-PR), released bound phenolics (RSBP), and their physical mixture (SDF-PR + RSBP). Three isomers of tri-p-coumaroyl spermidine were identified in the bound phenolic for the first time. Bound phenolics were covalently linked to dietary fiber by ester bonds. Compared with the other intervention groups, SDF-BP showed advantages in specific outcomes, particularly in significant alleviating splenomegaly, together with improvements in colonic morphology, mucus and physical barrier integrity. SDF-BP markedly restored the antioxidant capacity (CAT, GSH-Px) in DSS-induced colitis model. Both SDF-BP and SDF-PR + RSBP exhibited greater anti-inflammatory effects than the individual fractions, as evidenced by decreased IL-6 and increased IL-10 levels. Furthermore, SDF-BP decreased the abundance of Bacteroidaceae and Enterobacteriaceae, and increased Hungatella, Parabacteroides_goldsteinii, and Parasutterella, accompanied by alterations in purine, nucleotide, and glycerophospholipid metabolism. Spearman correlation analysis revealed significant associations between specific microbial taxa and lipid-, nucleotide-, and amino acid-related metabolites. Collectively, these findings suggest that the biological advantages of SDF-BP may be associated with the preservation of its native structural assembly, accompanied by coordinated alterations in gut microbial composition and host metabolic profiles. This study provides new insights into how the native dietary fiber and phenolics governs biological activity and highlights its potential for intestinal health management.