title: In vitro anti-Helicobacter pylori activity of a flavonoid rich extract of Glycyrrhiza glabra and its probable mechanisms of action.
abstract: BACKGROUND
  Glycyrrhiza glabra Linn. is regarded useful for peptic ulcer in traditional systems of medicine in India and Helicobacter pylori has been considered as one of the causative factors for peptic ulcer. Aim of the present study is to evaluate the anti-Helicobacter pylori action of GutGard(®), a flavonoid rich extract of Glycyrrhiza glabra and further to elucidate the possible mechanisms of its anti-Helicobacter pylori action.
  
  
  METHODS
  Agar dilution and microbroth dilution methods were used to determine the minimum inhibitory concentration of GutGard(®) against Helicobacter pylori. Protein synthesis, DNA gyrase, dihydrofolate reductase assays and anti-adhesion assay in human gastric mucosal cell line were performed to understand the mechanisms of anti-Helicobacter pylori activity of GutGard(®).
  
  
  RESULTS
  GutGard(®) exhibited anti-Helicobacter pylori activity in both agar dilution and microbroth dilution methods. Glabridin, the major flavonoid present in GutGard(®) exhibited superior activity against Helicobacter pylori while glycyrrhizin did not show activity even at 250 μg/ml concentration. In protein synthesis assay, GutGard(®) showed a significant time dependent inhibition as witnessed by the reduction in (35)S methionine incorporation into Helicobacter pylori ATCC 700392 strain. Additionally, GutGard(®) showed a potent inhibitory effect on DNA gyrase and dihydrofolate reductase with IC(50) value of 4.40 μg/ml and 3.33 μg/ml respectively. However, the extract did not show significant inhibition on the adhesion of Helicobacter pylori to human gastric mucosal cell line at the tested concentrations.
  
  
  CONCLUSIONS
  The present study shows that, GutGard(®) acts against Helicobacter pylori possibly by inhibiting protein synthesis, DNA gyrase and dihydrofolate reductase.
authors.affiliation: R&D Centre, Natural Remedies Pvt. Ltd., Bangalore, Karnataka, India.
authors.forename: Mannanthendil Kumaran
authors.initials: MK
authors.lastname: Asha
authors.forename: Debnath
authors.initials: D
authors.lastname: Debraj
authors.forename: D'souza
authors.initials: D
authors.lastname: Prashanth
authors.forename: Jothie Richard
authors.initials: JR
authors.lastname: Edwin
authors.forename: H S
authors.initials: HS
authors.lastname: Srikanth
authors.forename: Nithyanantham
authors.initials: N
authors.lastname: Muruganantham
authors.forename: Shekhar Michael
authors.initials: SM
authors.lastname: Dethe
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Anirban
authors.forename: Balachandran
authors.initials: B
authors.lastname: Jaya
authors.forename: Mundkinajeddu
authors.initials: M
authors.lastname: Deepak
authors.forename: Amit
authors.initials: A
authors.lastname: Agarwal
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D027081:DNA Gyrase / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology*; D005493:Folic Acid Antagonists / Q000494:pharmacology; D006035:Glycyrrhiza; D016480:Helicobacter pylori / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D059005:Topoisomerase II Inhibitors
chemical_list: D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D005419:Flavonoids; D005493:Folic Acid Antagonists; D010936:Plant Extracts; D059005:Topoisomerase II Inhibitors; D013762:Tetrahydrofolate Dehydrogenase; D027081:DNA Gyrase