In Vitro Effect of the Traditional Medicine Hainosan (Painongsan) on Porphyromonas gingivalis

Background: Hainosan (Painongsan) is a traditional Japanese and Chinese medicine that is used to treat several purulent diseases, including gingivitis and periodontitis. This formulation contains three crude drug components: The dried immature fruit of Citrus aurantium (Aurantii Fructus Immaturus), the dried root of Paeonia lactiflora (Paeoniae Radix), and the dried root of Platycodon grandiflorum (Platycodi Radix). Here we evaluated the in vitro antibacterial effects of hainosan extract (HNS) and extracts of its three components against Porphyromonas gingivalis, one of the pathogenic bacteria that causes periodontitis. Methods: The antibacterial activities of HNS and its components were examined by counting the number of colony-forming units (CFUs) and through transmission electron microscopy. Results: We found that HNS had direct antibacterial activity against three P. gingivalis isolates (JCM12257, JCM8525, and JCM19600), with HNS-treated cells being significantly smaller than those of untreated bacteria. Extracts of Platycodi Radix and Paeoniae Radix significantly suppressed the growth of P. gingivalis in a dose-dependent manner, with Platycodi Radix extract having the greatest antibacterial effect. In addition, P. gingivalis that were treated with Platycodi Radix extract were significantly larger than those treated with Aurantii Fructus Immaturus or Paeoniae Radix extracts. Further analysis showed that platycodin D, which is one of the ingredients of Platycodi Radix, reduced bacterial growth. Conclusions: Platycodi Radix is the active component in Hainosan and may represent a useful agent for the treatment of P. gingivalis-induced gingivitis and periodontitis.