In vitro susceptibility of the Gram-negative bacterium Helicobacter pylori to extracts of Iranian medicinal plants

The susceptibility of Helicobacter pylon to methanol extracts of 12 Iranian medicinal plants used in folk medicine for the treatment of gastric ailments including peptic ulcers disease was screened against one metronidazole-sensitive and one-metronidazole resistant strain of H. pylon using the disk diffusion method. Active extracts (zone of inhibition >= 15 mm) were then re-assayed to obtain the minimum inhibitory concentration (MIC) against 12 clinical isolates of H. pylon by using the agar dilution method. Extracts of the aerial part of Artemisia drocunculus L. (Compositae) and Teucrium polium L. (Lamiaceae), leaves of Salvia mirzayanii Rech. & Esfand. (Lamiaceae) and Salvia officinalis L. (Lamiaceae), flowers of Zataria multiflora Boiss. (Lamiaceae), fruits of Bunium persicum (Boiss.) B. Fedtsch. (Apiaceae), Carum carvi L. (Apiaceae), Heracleum persicum Desf. ex Fischer (Apiaceae), Pimpinella anisum L. (Apiaceae), Trochyspermum copticum (L.) Link (Apiaceae) and Myrtus communis L. (Myrtaceae), and seeds of Nigella sativa L. (Ranunculaceae) were evaluated in the study. Among them, S. mirzayanii had the strongest activity against H. pylon, with a MIC of 32 mu g/mL.