Coptis chinensis Extract-Loaded Mouthwash: Antimicrobial Efficacy, Biocompatibility, and Clinical Benefits for Periodontal Health

This study investigated the antimicrobial potential of Coptis chinensis rhizome extract against key oral pathogens and evaluated the safety and clinical efficacy of a CCE-loaded mouthwash. CCE exhibited broad-spectrum bactericidal activity, with low minimum inhibitory concentrations (0.002–0.008%) and minimum bactericidal concentrations (0.004–0.016%) against Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Time-kill kinetics revealed that CCE promptly eradicated Porphyromonas gingivalis. To balance antimicrobial potency and sensory acceptability, specifically the extract’s bitterness, we established the CCE concentrations in the mouthwash at 0.01% and 0.02% (w/v). Preclinical safety evaluations in animal models, including oral mucosal irritation and skin sensitization tests, confirmed the biocompatibility of 0.02% CCE, yielding “None” and “Non-sensitizer” ratings, respectively. Furthermore, a four-week, randomized, double-blind clinical trial (n = 73) revealed that 0.02% CCE mouthwash substantially reduced halitosis-inducing volatile sulfur compounds (hydrogen sulfide by 59.5% and methyl mercaptan by 50.0%). Significant improvements were also observed in the Plaque Index (55.2% reduction), Gingival Index (52.0% reduction), and Bleeding on Probing (77.3% reduction), with no adverse effects. These findings provide preliminary evidence that CCE mouthwash improves halitosis-related parameters and gingival indices in adults with self-reported halitosis, though further research is required to evaluate its long-term impact on broader periodontal disease states.