Antibacterial Effect of Kampo Herbal Formulation Hochu‐Ekki‐To (Bu‐Zhong‐Yi‐Qi‐Tang) on Helicobacter pyloriInfection in Mice

Because Helicobacter pylori (H. pylori)infection is a major cause of gastroduodenal diseases in humans, the eradication of H. pyloriusing antibiotics is very effective for the treatment of gastroduodenal diseases. However, it has recently been reported that resistance to these antibiotics is developing. In the present study, the antibacterial effect of a Kampo (traditional Japanese medicine) herbal formulation, Hochu‐ekki‐to (HET; Formula repletionis animalis et supletionis medii), against H. pyloriwas examined in vitroand in vivo. HET inhibited the growth of antibiotic‐resistant strains of H. pylorias well as antibiotic‐sensitive strains at a dose of 2.5 mg/ml in vitro. When 1,000 mg/kg of HET was administered orally to C57BL/6 mice for 7 days before or after inoculation with H. pylori, H. pyloriin the stomach was significantly reduced in the HET‐pre‐treatment group compared with the control group. Furthermore, HET in combination with antibiotics completely eradicated the bacteria in mice. The expression of interferon (IFN)‐γ was induced in the gastric mucosa of the mice pre‐treated with HET. There were no significant differences between the colonization of H. pyloriin the control and HET treatment groups in IFN‐γ gene‐deficient mice. These results suggest that the antibacterial effect of HET may be partly due to IFN‐γ induction, and that HET may be clinically useful for treatment of H. pyloriinfection.