title: Antiadhesive properties of Abelmoschus esculentus (Okra) immature fruit extract against Helicobacter pylori adhesion.
abstract: BACKGROUND
  Traditional Asian and African medicine use immature okra fruits (Abelmoschus esculentus) as mucilaginous food to combat gastritis. Its effectiveness is due to polysaccharides that inhibit the adhesion of Helicobacter pylori to stomach tissue. The present study investigates the antiadhesive effect in mechanistic detail.
  
  
  METHODS
  A standardized aqueous fresh extract (Okra FE) from immature okra fruits was used for a quantitative in vitro adhesion assay with FITC-labled H. pylori J99, 2 clinical isolates, AGS cells, and fluorescence-activated cell sorting. Bacterial adhesins affected by FE were pinpointed using a dot-blot overlay assay with immobilized Lewis(b), sialyl-Lewis(a), H-1, laminin, and fibronectin. (125)I-radiolabeled Okra FE polymer served for binding studies to different H. pylori strains and interaction experiments with BabA and SabA. Iron nanoparticles with different coatings were used to investigate the influence of the charge-dependence of an interaction on the H. pylori surface.
  
  
  RESULTS
  Okra FE dose-dependently (0.2 to 2 mg/mL) inhibited H. pylori binding to AGS cells. FE inhibited the adhesive binding of membrane proteins BabA, SabA, and HpA to its specific ligands. Radiolabeled compounds from FE bound non-specifically to different strains of H. pylori, as well as to BabA/SabA deficient mutants, indicating an interaction with a still-unknown membrane structure in the vicinity of the adhesins. The binding depended on the charge of the inhibitors. Okra FE did not lead to subsequent feedback regulation or increased expression of adhesins or virulence factors.
  
  
  CONCLUSIONS
  Non-specific interactions between high molecular compounds from okra fruits and the H. pylori surface lead to strong antiadhesive effects.
authors.affiliation: University of Münster, Institute of Pharmaceutical Biology and Phytochemistry, Münster, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Messing
authors.affiliation: University of Münster, Institute of Pharmaceutical Biology and Phytochemistry, Münster, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Thöle
authors.affiliation: University of Münster, Institute of Pharmaceutical Biology and Phytochemistry, Münster, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Niehues
authors.affiliation: Umeå University, Medical Biochemistry and Biophysics, Umeå, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Shevtsova
authors.affiliation: University Hospital Freiburg, Reference Centre for Helicobacter pylori, Department of Medical Microbiology and Hygiene, Freiburg, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Glocker
authors.affiliation: Umeå University, Medical Biochemistry and Biophysics, Umeå, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Borén
authors.affiliation: University of Münster, Institute of Pharmaceutical Biology and Phytochemistry, Münster, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hensel
mesh_terms: D028483:Abelmoschus / Q000737:chemistry*; D018829:Adhesins, Bacterial / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000187:drug effects*; D001667:Binding, Competitive; D045744:Cell Line, Tumor; D005638:Fruit / Q000737:chemistry*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D016480:Helicobacter pylori / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D006384:Hemagglutination / Q000187:drug effects; D006801:Humans; D010936:Plant Extracts / Q000378:metabolism / Q000494:pharmacology*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity
chemical_list: D018829:Adhesins, Bacterial; D010936:Plant Extracts; D011134:Polysaccharides; D012333:RNA, Messenger