Ellagic Acid From Xinjiangpomegranate Inhibits Caries:Bacterial And Animal Models

This study investigates the anti-cariogenic potential of ellagic acid (EA) extracted from Xinjiang Punica granatum peel using in vitro bacterial experiments and in vivo animal models, exploring its inhibitory effects on cariogenic bacteria and biofilms. In vitro experiments: Broth microdilution determined minimum inhibitory concentration (MIC50) and minimum bactericidal concentration (MBC) of EA against Streptococcus mutans, S. sobrinus, and S. sanguinis. Modified Robbins device and crystal violet staining measured minimum biofilm inhibitory concentration (MBIC50). Live/dead staining visualized bacterial viability in mixed biofilms. Fluorescence labeling quantified adhesion of EA-treated S. mutans to saliva-coated hydroxyapatite. In vivo experiments: Rat caries model (n=30, Ethics #2025-089) evaluated salivary bacterial counts, caries severity (Keyes score, X-ray, fluorescent staining), and systemic safety via hematology, histopathology, and organ coefficients. In vitro: MIC50/MBC for S. mutans: 4/8 mM; S. sobrinus: 2/4 mM; S. sanguinis: 8/16 mM. MBIC50 for S. mutans/S. sobrinus: 16 mM; S. sanguinis: 32 mM. 8–16 mM EA altered live/dead bacterial ratios in biofilms; 4 mM disrupted biofilm structure. Adhesion inhibition of S. mutans showed dose-dependent effects. In vivo: 2–8 mM EA reduced salivary S. mutans (p<0.05) and caries scores without systemic toxicity. Ellagic acid from Xinjiang Punica granatum peel effectively inhibits cariogenic bacteria and biofilms in vitro and prevents dental caries in rats in vivo, supporting its potential as a natural anti-cariogenic agent.