Antimicrobial activity of essential oils against Helicobacter pylori.
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.
Ohno
Tomoyuki
T
Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
Kita
Masakazu
M
Yamaoka
Yoshio
Y
Imamura
Shigeyoshi
S
Yamamoto
Toshiro
T
Mitsufuji
Shoji
S
Kodama
Tadashi
T
Kashima
Kei
K
Imanishi
JirO
J
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
D000900:Anti-Bacterial Agents; D002021:Buffers; D009822:Oils, Volatile; D010938:Plant Oils; D013729:Terpenes; C052901:lemongrass oil; D017291:Clarithromycin