ABSTRACT
Due to increasing emergence of drug-resistance in Helicobacter pylori isolates, traditional plants are potentially valuable sources of novel anti-H. pylori agents. In this research, anti-H. pylori activity of the organic extracts of twenty native Iranian plants was determined against ten clinical isolates of H. pylori. Disc diffusion was used to determine the biological activity of 20 plant extracts as well as 8 antibiotics commonly used to treat H. pylori infections. Minimum inhibitory concentrations were also measured by tube and agar dilution methods for the biologically active plant extracts. Of the twenty plant extracts analyzed, sixteen exhibited good anti-H. pylori activity, using disc diffusion. The ten most active extracts were Carum bulbocastanum, Carum carvi, Mentha longifolia, Saliva limbata, Saliva sclarea, Ziziphora clinopodioides, Thymus caramanicus, Glycyrrhiza glabra, Xanthium brasilicum and Trachyspermum copticum. Minimum inhibitory concentrations measured for the 10 biologically active plant extracts were within the range of 31.25 to 500 micro g/ml. Among the ten plant extracts effective against H. pylori clinical isolates, Carum carvi, Xanthium brasilicum and Trachyspermum copticum showed the highest activity