title: The effectiveness of jewelweed, Impatiens capensis, the related cultivar I. balsamina and the component, lawsone in preventing post poison ivy exposure contact dermatitis.
abstract: BACKGROUND
  Impatiens capensis (jewelweed) is native to the Eastern and Midwestern US and Canada. Many Native American tribes used I. capensis and its close relatives to treat/prevent rash from plant sources particularly Toxicodendron radicans and Urtica dioica. I. balsamina (garden balsam) a native of China was used by the indigenous people of Asia for similar purposes.
  
  
  OBJECTIVE
  This study aims to validate ethnopharmacological use of jewelweed in poison ivy (PI) dermatitis prevention and to refute scientific papers denying this efficacy. Additionally, the content of lawsone, the purported effective agent in jewelweed preparations, was measured to see if its concentration correlated with jewelweed preparation efficacy.
  
  
  METHODS
  Poison ivy was brushed onto forearms of volunteers in 6 locations and exposed areas were treated with jewelweed extracts, fresh plant mashes, soaps made of plant extracts, water and Dawn® dish soap. Rash development was scored on a scale of 0-14.
  
  
  RESULTS
  Jewelweed mash was effective in reducing poison ivy dermatitis, supporting ethnobotanical use. However, jewelweed extracts were not effective; and soaps made of these extracts were effective but no more so than jewelweed-free soaps. Lawsone content varied with harvest season and did not appear to affect rash development.
  
  
  CONCLUSIONS
  Jewelweed is an efficacious plant for preventing development of dermatitis following poison ivy contact, but soap is more effective. Lawsone content does not correlate with PI rash prevention. Perhaps saponins, the soapy component of jewelweed are the effective agents.
authors: Department of Biological and Allied Health Sciences, Ohio Northern University, 525 South Main Street Ada, OH 45810, USA. v-motz@onu.edu
authors: Vicki
authors: V
authors: Abrams Motz
authors: Christopher P
authors: CP
authors: Bowers
authors: Linda
authors: L
authors: Mull Young
authors: David H
authors: DH
authors: Kinder
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D011040:Dermatitis, Toxicodendron / Q000517:prevention & control*; D006801:Humans; D029069:Impatiens / Q000737:chemistry* / Q000145:classification; D008875:Middle Aged; D009285:Naphthoquinones / Q000494:pharmacology*; D028321:Plant Preparations / Q000494:pharmacology / Q000627:therapeutic use*; D012621:Seasons; D012915:Soaps; D013045:Species Specificity; D012251:Toxicodendron / Q000009:adverse effects*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D009285:Naphthoquinones; D028321:Plant Preparations; D012915:Soaps; C005090:lawsone