Inhibition of Helicobacter pylori growth and its colonization factors by Parthenium hysterophorus extracts

Ethnopharmacological relevance: Parthenium hysterophorus (Asteraceae) is a traditional medicinal plant used to treat gastrointestinal disorders, such as gastritis. Helicobacter pylori have been described as the etiological agent of gastritis, peptic ulcer, as well as gastric adenocarcinoma. 50% of the world's population is infected with this bacterium and the current therapy fails due to the increment in antibiotic resistance; therefore, it is necessary to find new approaches to control H. pylori infection, either by its eradication or by preventing the bacterial colonization. Aim of the study: To investigate the effect of P. hysterophorus extracts on H. pylori growth and upon its colonization-related factors. Materials and methods: Five different polarity extracts from roots and aerial parts of P. hysterophorus were evaluated in vitro against H. pylori growth by the broth dilution method. Anti-colonization activities were determined as follows: motility in soft agar plates, urease activity by ammonia colorimetrical quantification, and adherence of FITC labeled H. pylori to AGS cells by fluorometrical measurement. Results: Organic extracts inhibited H. pylori growth. Particularly, the dichloromethane extract from roots showed a MIC of 15.6 mu g/ml while the aqueous extracts showed low or null activity. There is a direct correlation between antibacterial activity and inhibition of motility. Unease activity was partially inhibited by organic extracts, at best 46%, except for the roots dichloromethane extract which reached 74% of inhibition with 500 mu g/ml (IC50= 136.4 mu g/ml). Plant extracts inhibited adherence in different ranges but the dichloromethane-methanol ones possessed the highest effect, with a 70% maximal inhibition at 1 mg/ml. Conclusion: The results indicate that some P. hysterophorus extracts have various biological activities that could act synergistically against H. pylori. This work contributes to the ethnomedical knowledge of this species and underlines the potential of some organic extracts as a good source for the isolation of bioactive compounds. (c) 2015 Elsevier Ireland Ltd. All rights reserved.