Bactericidal and Anti-Inflammatory Effects of Ashitaba-Extract Ameliorate the Gingivitis and Halitosis in Dogs with Porphyromonas gulae-Infected Periodontal Disease

<i>Ashitaba</i> (<i>Angelica keiskei</i>) is a perennial herb native to Japan, traditionally consumed as a health-promoting food and herbal medicine. This study evaluated the antimicrobial, anti-halitosis, and anti-inflammatory effects of <i>Ashitaba</i> extract on canine periodontal disease (PD) caused by <i>Porphyromonas gulae</i> (<i>P. gulae</i>). In vitro, <i>Ashitaba</i> extract (0.006-0.1%) significantly inhibited <i>P. gulae</i> viability by up to 80% and reduced biofilm formation by approximately 10% at 0.1%. The extract also suppressed the production of volatile sulfur compounds-hydrogen sulfide and methyl mercaptan-by over 80% and 40%, respectively, within 10 min. Furthermore, <i>Ashitaba</i> extract markedly decreased <i>P. gulae</i>-induced pro-inflammatory cytokine secretion (IL-1β, IL-6, TNF-α) by up to 90% in murine, canine, and human macrophage and gingival cell lines. In vivo, daily oral application of 0.05% <i>Ashitaba</i>-extract gel for four weeks, with or without tooth brushing, significantly improved gingivitis scores (by 40-60%), reduced halitosis levels, and decreased <i>P. gulae</i> DNA detection and enzymatic activity in dogs with PD. These findings demonstrate that <i>Ashitaba</i> extract possesses potent bactericidal, anti-halitosis, and anti-inflammatory properties, supporting its potential as a natural adjunctive therapy for the prevention and management of canine periodontal disease.