Pentagalloylglucose and tannic acid improve intestinal health by protecting the mucus barrier from Clostridium perfringens-induced degradation.

BACKGROUND

Clostridium perfringens degrades the intestinal mucus layer, further contributing to intestinal infections and diarrhea. Gallotannins protect the intestinal tract and alleviate diarrhea, but the mechanism involved is unknown.

OBJECTIVE

This study aimed to elucidate the mechanisms by which pentagalloylglucose (PGG) and tannic acid (TA) inhibit C. perfringens, protect the intestinal mucus layer, and alleviate diarrhea.

METHODS

The bactericidal activity and biofilm disruption were studied via proteomics, Raman spectroscopy, and Zeta potential. The mucus layer was analyzed through atomic force microscopy, viscoelasticity assays, and molecular dynamics simulations. The protective effects of PGG and TA on epithelial cells were studied using a C. perfringens-mucus-epithelial cell model. A C. perfringens mouse model was established to investigate the protective effects of PGG and TA on mice.

RESULTS

PGG and TA displayed strong bactericidal activity at 125 µg/ml, inhibiting bacterial sliding, disrupting biofilm formation, and inducing bacterial aggregation. Membrane protein analysis revealed structural alterations and upregulation of pathways related to membrane permeability, quorum sensing, oxidative phosphorylation, and ABC transporters. These effects increased bacterial stress and accelerated cell death. Molecular docking confirmed that PGG and TA interact with membrane proteins through specific intermolecular forces. C. perfringens infection reduces mucus viscoelasticity and increases roughness. At 7.8 µg/ml, PGG and TA bound to the cysteine-rich region of mucin 2 via intermolecular forces. This enhances viscoelasticity, improving cross-linking and reducing surface roughness. In a coculture model, PGG or TA regulated the expression of inflammatory cytokines and improved cell viability. In C. perfringens-infected mice, PGG and TA significantly alleviated weight loss and effectively restored the inner mucus layer thickness and goblet cell counts (p < 0.05), while concurrently suppressing the overexpression of pro-inflammatory cytokines (IL-1β and IL-6; p<0.05) and downregulated abnormally elevated intestinal barrier and proliferation markers (Ascl2 and Lgr5; p<0.05). Correlation analysis further revealed an inverse relationship, suggesting that the compromised physical mucus defense triggers a compensatory upregulation of mucosal immune signaling and epithelial renewal mechanisms.

CONCLUSION

This study reveals that PGG and TA exert antidiarrheal effects through a dual mechanism-inhibiting C. perfringens proliferation and enhancing intestinal mucus barrier integrity-and first elucidates the molecular regulatory pathways underlying the interaction between tannins and the pathogen-mucus layer interplay, offering novel targeted strategies for the treatment of infectious diarrhea.