Journal of Medicinal Plants Research Vol. 6(21), pp. 3749-3753, 9 June, 2012 Available online at http://www.academicjournals.org/JMPR DOI: 10.5897/JMPR11.1725 ISSN 1996-0875 ©2012 Academic Journals Full Length Research Paper Comparison of in vitro antimicrobial effect of ethanol extracts of Satureja khuzestanica, Rhus coriaria, and Ocimum basilicum L. on Helicobacter pylori Yousef Motaharinia 1 , Mohammad Saleh Hazhir 2 , Mohammad Ali Rezaee 1 , Siamak Vahedi 3 , Ahmad Rashidi 1 , Werya Hosseini 1 , Mohammad Saeed Hakhamaneshi 2 and Mohammad Reza Rahmani 1 * 1 Department of Immunology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran. 2 Department of Biochemistry and Nutrition, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran. 3 Department of Internal Medicine, Faculty of medicine, Besat Hospital, Kurdistan University of Medical Sciences, Sanandaj, Iran. Accepted 17 February, 2012 Helicobacter pylori is the main reason of gastritis, gastric ulcer and cancer, which cause many therapeutic problems for man, throughout the world. Therefore, the aim of the current study is to compare the antimicrobial effect of the extracts of Satureja khuzestanica, Rhus coriaria, and Ocimum basilicum L. on H. pylori. To isolate H. pylori, sampling was performed in 30 patients of the endoscopy ward of Be’sat Hospital, Sanandaj. Ethanol extracts of S. khuzestanica, R. coriaria and O. basilicum L. were prepared. Using disc diffusion and agar dilution methods, the antimicrobial effects of the plant extracts against H. pylori were evaluated. Seven strains of H. pylori were isolated from the biopsy samples. The results of disc diffusion demonstrated that the mean diameter of no-growth halo for the discs containing 20 mg of S. khuzestanica, R. coriaria and O. basilicum L. were ≥ 12.28, ≥ 19.42, and ≥ 11.42 mm, respectively. The values for the discs containing 40 mg of the extracts were ≥ 20.14, ≥ 28.57, and ≥ 13.57 mm, respectively. The mean diameter of no-growth halo for gentamicin (10 μg/ml con.) as the positive control was obtained to be ≥ 37.85 mm. The results of agar dilution method showed that the minimum inhibitory concentration (MIC) of the extracts of S. khuzestanica, R. coriaria, and O. basilicum L. were 307.14, 214.28, and 392.8 μg/ml, respectively. The study showed that the ethanol extract of R. coriaria and S. khuzestanica had antibacterial effect against H. pylori. Key words: Satureja khuzestanica, Rhus coriaria, Ocimum basilicum L., H. pylori, antibacterial effect. INTRODUCTION Helicobacter pylori is a spiral-shaped Gram-negative micro-aerobic bacterium, which is found in the stomach of most people. The bacterium has infected more than half of the world population, and is the agent of gastro- intestinal diseases such as peptic ulcer, chronic gastritis, and dyspepsia in 10% of infected individuals (Wen and Moss, 2009). In the past 20 years, some evidence indicating the role of the bacterium in development of *Corresponding author. E-mail: rahmany191@gmail.com. Tel: +98-871-6131412. gastric cancer has been obtained. Therefore, the World Health Organization (WHO) in 1994 introduced H. pylori as the first carcinogen factor, and reported that the bacterium is responsible for 63% of the gastric cancer cases (Wen and Moss, 2009). In developing countries such as Iran, the infection rate is high, such that in some areas, 90% of the adults are infected (Saberi-Firoozi and Nejabat, 2006). Gastric cancer is a known fatal disease around the world. It is estimated that in 2010 more than 1.1 million individuals were affected by the disease. Gastric cancer is the second cancer in men and fourth cancer in women that leads to death. Epidemiological studies have shown that the developing countries,