title: The defense substance allicin from garlic permeabilizes membranes of Beta vulgaris, Rhoeo discolor, Chara corallina and artificial lipid bilayers.
abstract: BACKGROUND
  Allicin (diallylthiosulfinate) is the major volatile- and antimicrobial substance produced by garlic cells upon wounding. We tested the hypothesis that allicin affects membrane function and investigated 1) betanine pigment leakage from beetroot (Beta vulgaris) tissue, 2) the semipermeability of the vacuolar membrane of Rhoeo discolor cells, 3) the electrophysiology of plasmalemma and tonoplast of Chara corallina and 4) electrical conductivity of artificial lipid bilayers.
  
  
  METHODS
  Garlic juice and chemically synthesized allicin were used and betanine loss into the medium was monitored spectrophotometrically. Rhoeo cells were studied microscopically and Chara- and artificial membranes were patch clamped.
  
  
  RESULTS
  Beet cell membranes were approximately 200-fold more sensitive to allicin on a mol-for-mol basis than to dimethyl sulfoxide (DMSO) and approximately 400-fold more sensitive to allicin than to ethanol. Allicin-treated Rhoeo discolor cells lost the ability to plasmolyse in an osmoticum, confirming that their membranes had lost semipermeability after allicin treatment. Furthermore, allicin and garlic juice diluted in artificial pond water caused an immediate strong depolarization, and a decrease in membrane resistance at the plasmalemma of Chara, and caused pore formation in the tonoplast and artificial lipid bilayers.
  
  
  CONCLUSIONS
  Allicin increases the permeability of membranes.
  
  
  CONCLUSIONS
  Since garlic is a common foodstuff the physiological effects of its constituents are important. Allicin's ability to permeabilize cell membranes may contribute to its antimicrobial activity independently of its activity as a thiol reagent.
authors.affiliation: Department of Plant Physiology (Bio III), RWTH Aachen University, 52056 Aachen, Germany.
authors.forename: Martin C H
authors.initials: MC
authors.lastname: Gruhlke
authors.affiliation: FB5 Biophysik, Universität Osnabrück, 49069 Osnabrück, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Hemmis
authors.affiliation: Department of Plant Physiology (Bio III), RWTH Aachen University, 52056 Aachen, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Noll
authors.affiliation: FB5 Biophysik, Universität Osnabrück, 49069 Osnabrück, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Wagner
authors.affiliation: Institut für Pflanzenwissenschaften (IBG-2), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
authors.forename: Hinrich
authors.initials: H
authors.lastname: Lühring
authors.affiliation: Department of Plant Physiology (Bio III), RWTH Aachen University, 52056 Aachen, Germany. Electronic address: alan.slusarenko@bio3.rwth-aachen.de.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Slusarenko
mesh_terms: D027461:Beta vulgaris / Q000187:drug effects* / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D044784:Chara / Q000187:drug effects* / Q000378:metabolism; D034821:Commelinaceae / Q000187:drug effects* / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004220:Disulfides; D005737:Garlic / Q000737:chemistry*; D008051:Lipid Bilayers / Q000378:metabolism*; D010860:Pigments, Biological / Q000378:metabolism; D013441:Sulfinic Acids / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D004220:Disulfides; D008051:Lipid Bilayers; D010860:Pigments, Biological; D013441:Sulfinic Acids; C006452:allicin; D004121:Dimethyl Sulfoxide
keywords: Allicin; Antimicrobial; Electrophysiology; Lipid bilayers; Membranes