title: Antimicrobial activity of essential oils against Helicobacter pylori.
abstract: BACKGROUND
  Helicobacter pylori is an important pathogen responsible for gastroduodenal diseases in humans. Although the eradication of H. pylori using antibiotics often improves gastroduodenal diseases, resistance to the antibiotics is emerging.
  
  
  METHODS
  The antimicrobial effect of essential oils and the development of resistance to the essential oils were evaluated in vitro and in vivo.
  
  
  RESULTS
  Thirteen essential oils used in this study completely inhibited the growth of H. pylori in vitro at a concentration of 0.1% (v/v). Cymbopogon citratus (lemongrass) and Lippia citriodora (lemon verbena) were bactericidal against H. pylori at 0.01% at pH 4.0 and 5.0. Resistance to lemongrass did not develop even after 10 sequential passages, whereas resistance to clarithromycin developed under the same conditions. In in vivo studies, the density of H. pylori in the stomach of mice treated with lemongrass was significantly reduced compared with untreated mice.
  
  
  CONCLUSIONS
  These results demonstrate that the essential oils are bactericidal against H. pylori without the development of acquired resistance, suggesting that essential oils may have potential as new and safe agents for inclusion in anti-H. pylori regimens.
authors.affiliation: Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ohno
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kita
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamaoka
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Imamura
authors.forename: Toshiro
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Shoji
authors.initials: S
authors.lastname: Mitsufuji
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kodama
authors.forename: Kei
authors.initials: K
authors.lastname: Kashima
authors.forename: JirO
authors.initials: J
authors.lastname: Imanishi
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002021:Buffers; D017291:Clarithromycin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D032411:Lippia; D051379:Mice; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000494:pharmacology*; D008517:Phytotherapy; D010938:Plant Oils / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002021:Buffers; D009822:Oils, Volatile; D010938:Plant Oils; D013729:Terpenes; C052901:lemongrass oil; D017291:Clarithromycin