Oral treatment with catechin isolated from Japanese green tea significantly inhibits the growth of periodontal pathogen Porphyromonas gulae and ameliorates the gingivitis and halitosis caused by periodontal disease in cats and dogs.

It has been postulated that 90 % of cats and dogs develop periodontal disease by 1 year of age. Periodontal disease develops because of infection by multiple bacteria, including Porphyromonas gulae (P. gulae) and Porphyromonas gingivalis (P. gingivalis), resulting in severe gingivitis, halitosis, and bone lysis. Because periodontal disease is an irreversible disorder, preventive dentistry in veterinary medicine has become pertinent. This study examined the efficacy of catechin isolated from green tea by focusing on its bactericidal effects against P. gulae and P. gingivalis, inhibition of inflammation, and reduction in halitosis in dogs and cats with periodontal disease. The viability of P. gulae and P. gingivalis was significantly inhibited by catechin in a dose-dependent manner in vitro. P. gulae- and P. gingivalis-associated biofilm formation was also significantly suppressed by catechin, but the effect was not as drastic as the bactericidal effect. Hydrogen sulfide and methyl mercaptan generated by P. gulae and P. gingivalis were significantly decreased by catechin, even after a short exposure. Pro-inflammatory cytokine production and phosphorylation of P-38 and JNK induced by P. gulae were inhibited by catechin treatment in a dose-dependent manner. Treatment with 0.01892 % catechin-contained wet food for 1 month (30-35 days) significantly ameliorated halitosis and P. gulae activity, but had no impact on dental plaque and gingivitis. Our findings indicate that oral treatment with catechin can prevent periodontal diseases in both dogs and cats.