title: Interactions of extracts from selected chewing stick sources with Aggregatibacter actinomycetemcomitans.
abstract: BACKGROUND
  Aggregatibacter actinomycetemcomitans produces a leukotoxin that activates a pro-inflammatory death of human monocytes/macrophages. A specific clone of this bacterium (JP2) has a 530-base pair deletion in the leukotoxin promoter gene and significantly enhanced expression of leukotoxin. This specific clone of A. actinomycetemcomitans is common in some African populations and has a strong association with periodontal attachment loss in adolescents in these populations. Chewing sticks of plant origin are commonly used as oral hygiene tool in Africa, but their role as a therapeutic agent in periodontal disease is poorly investigated.
  
  
  RESULTS
  Ethanol extracts were made from 7 common plants used as chewing sticks in West-Africa. None of the tested extracts inhibited growth of A. actinomycetemcomitans. However, extracts from Psidium guajava (Guava) completely neutralized the cell death and pro-inflammatory response of human leukocytes induced by the leukotoxin. None of the six other tested chewing stick extracts showed this effect.
  
  
  CONCLUSIONS
  The discovery that extracts from Guava efficiently neutralizes A. actinomycetemcomitans leukotoxicity might lead to novel therapeutic agents and strategies for prevention and treatment of aggressive forms of periodontitis induced by infections with the highly leukotoxic JP2 clone of this bacterium.
authors.affiliation: Dental School University of Ghana, Accra, Ghana.
authors.forename: Francis
authors.initials: F
authors.lastname: Kwamin
authors.forename: Rolf
authors.initials: R
authors.lastname: Gref
authors.forename: Dorte
authors.initials: D
authors.lastname: Haubek
authors.forename: Anders
authors.initials: A
authors.lastname: Johansson
mesh_terms: D000293:Adolescent; D016976:Aggregatibacter actinomycetemcomitans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D003742:Dental Devices, Home Care; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005098:Exotoxins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*; D005638:Fruit / Q000737:chemistry; D006801:Humans; D007962:Leukocytes / Q000187:drug effects; D009154:Mutation; D009910:Oral Hygiene / Q000295:instrumentation / Q000379:methods; D010936:Plant Extracts / Q000378:metabolism / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D031647:Psidium / Q000737:chemistry
chemical_list: D005098:Exotoxins; D010936:Plant Extracts; C018579:leukotoxin