Aspergillus oryzae fermentation modifies the composition of Massa Medicata Fermentata and its effects on the gut microbiota in mice with spleen-deficiency constipation

This study investigated the effects of Aspergillus oryzae fermentation on the chemical composition of Massa Medicata Fermentata (MMF) and the gut microbiota in mice with spleen-deficiency constipation by directly comparing unfermented MMF (UFL) with A. oryzae -fermented MMF (AOFL). We examined whether A. oryzae fermentation altered the small-molecule chemical profile of MMF and whether, compared with UFL, AOFL was associated with more pronounced changes in selected host functional indices and gut microbial profiles. The model was induced using Folium Sennae decoction, restricted water access, and a low-fiber diet, after which mice received UFL or AOFL. Untargeted LC–MS was used to characterize putatively annotated chemical features in the two preparations. Fecal water content, serum D-xylose, motility-related serum markers, hepatic oxidative-stress indices, colonic histology, concentrations of short-chain fatty acids (SCFAs) in colonic contents, and 16S rRNA-based microbial profiles were assessed in parallel. Fermentation with A. oryzae altered the putatively annotated chemical profile of MMF; L-phenylalanine and hypoxanthine showed significantly higher relative signal intensities in AOFL, whereas the other selected features showed nonsignificant directional differences. Relative to UFL, AOFL showed higher serum D-xylose, 5-hydroxytryptamine, and motilin levels, greater hepatic superoxide dismutase activity, and longer colonic crypts. Relative to the model group, AOFL showed lower malondialdehyde and vasoactive intestinal peptide levels and higher gastrin levels and goblet cell number. Microbiota analysis suggested that AOFL partially shifted the disturbed community structure toward the normal-control pattern and altered predicted metabolic functions. None of the measured SCFAs differed significantly between the AOFL and model groups; acetate and propionate were numerically higher with AOFL, whereas butyrate showed no corresponding recovery. Overall, A. oryzae fermentation altered the putatively annotated chemical composition of MMF and was associated with a partial shift in gut microbial composition and more pronounced changes in selected host functional indices than UFL.