title: Honey - a potential agent against Porphyromonas gingivalis: an in vitro study.
abstract: BACKGROUND
  Honey has been discussed as a therapeutic option in wound healing since ancient time. It might be also an alternative to the commonly used antimicrobials in periodontitis treatment. The in-vitro study was aimed to determine the antimicrobial efficacy against Porphyromonas gingivalis as a major periodontopathogen.
  
  
  METHODS
  One Manuka and one domestic beekeeper honey have been selected for the study. As a screening, MICs of the honeys against 20 P. gingivalis strains were determined. Contents of methylglyoxal and hydrogen peroxide as the potential antimicrobial compounds were determined. These components (up to 100 mg/l), propolis (up to 200 mg/l) as well as the two honeys (up to 10% w/v) were tested against four P. gingivalis strains in planktonic growth and in a single-species biofilm.
  
  
  RESULTS
  2% of Manuka honey inhibited the growth of 50% of the planktonic P. gingivalis, the respective MIC50 of the German beekeeper honey was 5%. Manuka honey contained 1.87 mg/kg hydrogen peroxide and the domestic honey 3.74 mg/kg. The amount of methylglyoxal was found to be 2 mg/kg in the domestic honey and 982 mg/kg in the Manuka honey. MICs for hydrogen peroxide were 10 mg/l - 100 mg/l, for methylglyoxal 5 - 20 mg/l, and for propolis 20 mg/l - 200 mg/l. 10% of both types of honey inhibited the formation of P. gingivalis biofilms and reduced the numbers of viable bacteria within 42 h-old biofilms. Neither a total prevention of biofilm formation nor a complete eradication of a 42 h-old biofilm by any of the tested compounds and the honeys were found.
  
  
  CONCLUSIONS
  Honey acts antibacterial against P. gingivalis. The observed pronounced effects of Manuka honey against planktonic bacteria but not within biofilm can be attributed to methylglyoxal as the characteristic antimicrobial component.
authors.affiliation: Department of Periodontology, Laboratory of Oral Microbiology, Dental School, University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. sigrun.eick@zmk.unibe.ch.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Eick
authors.forename: Gesine
authors.initials: G
authors.lastname: Schäfer
authors.forename: Jakub
authors.initials: J
authors.lastname: Kwieciński
authors.forename: Julia
authors.initials: J
authors.lastname: Atrott
authors.forename: Thomas
authors.initials: T
authors.lastname: Henle
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Pfister
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D056705:Apitherapy; D018441:Biofilms / Q000187:drug effects; D006722:Honey / Q000032:analysis / Q000145:classification; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis / Q000494:pharmacology; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000254:growth & development; D011429:Propolis / Q000494:pharmacology; D011765:Pyruvaldehyde / Q000032:analysis / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D011765:Pyruvaldehyde; D011429:Propolis; D006861:Hydrogen Peroxide