Punicalagin Enhances Odontogenic Differentiation and Reparative Dentin Formation via Wnt/β-Catenin Signalling.

AIM: Punicalagin (PCG), a natural polyphenol derived from pomegranate peel, possesses well-established antibacterial and anti-inflammatory properties. However, whether PCG promotes odontogenic differentiation of human dental pulp stem cells (DPSCs) remains unclear. This study investigated the effects of PCG on odontogenic differentiation and reparative dentin formation and further explored the underlying molecular mechanism. METHODS: A rat pulpitis model was established to evaluate the effects of a PCG-loaded collagen sponge on pulpal repair. Pulpal inflammation and reparative dentin formation were assessed histologically. DPSCs were isolated and treated with PCG (5 μM). Cell viability, odontogenic differentiation, and Wnt/β-catenin signalling were evaluated using CCK-8, alkaline phosphatase (ALP) and Alizarin Red S staining, quantitative real-time polymerase chain reaction, Western blotting, immunofluorescence, and DKK-1 inhibition assays. RESULTS: PCG application significantly reduced inflammatory infiltration and stimulated reparative dentin formation in the rat pulpitis model. At the cellular level, PCG enhanced the odontogenic differentiation of DPSCs and upregulated key odontogenic markers (ALP, Runx2, DMP-1, and DSPP) at both the gene and protein levels. Mechanistically, PCG promoted the nuclear translocation of β-catenin, consistent with activation of the canonical Wnt/β-catenin signalling pathway. The pro-odontogenic effects of PCG were largely attenuated by DKK-1-mediated inhibition of canonical Wnt signalling. CONCLUSION: PCG promoted the odontogenic differentiation of DPSCs at least in part through activation of the Wnt/β-catenin signalling pathway. These findings identify PCG as a promising modulator of odontogenic differentiation and provide mechanistic evidence supporting its further investigation for dentin-pulp repair. CLINICAL RELEVANCE: These findings provide a biological rationale for further investigation of PCG-containing strategies for vital pulp therapy.