Department of Biological and Allied Health Sciences, Ohio Northern University, 525 South Main Street Ada, OH 45810, USA.
J Ethnopharmacol. 2012 Aug 30;143(1):314-8. doi: 10.1016/j.jep.2012.06.038. Epub 2012 Jul 3.
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.
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.
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.
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.
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.
Impatiens capensis（凤仙花）原产于美国东部和中西部以及加拿大。许多美洲原住民部落使用 I. capensis 及其近亲来治疗/预防植物源皮疹，特别是 Toxicodendron radicans 和 Urtica dioica。原产于中国的 I. balsamina（花园凤仙花）被亚洲的土著人民用于类似的目的。
本研究旨在验证凤仙花在预防毒葛性皮炎方面的民族药理学用途，并反驳否认这种功效的科学论文。此外，还测量了作为凤仙花制剂中据称有效成分的 lawsone 的含量，以观察其浓度是否与凤仙花制剂的功效相关。
将毒葛刷到志愿者的前臂 6 个部位，暴露的区域用凤仙花提取物、新鲜植物糊剂、植物提取物制成的肥皂、水和 Dawn®餐具洗涤剂进行处理。皮疹发展程度按 0-14 分进行评分。
凤仙花糊剂在减少毒葛性皮炎方面有效，支持民族植物学的应用。然而，凤仙花提取物无效；而由这些提取物制成的肥皂虽然有效，但并不比不含凤仙花的肥皂更有效。lawsone 的含量随收获季节而变化，似乎不会影响皮疹的发展。
凤仙花是一种有效的植物，可以预防接触毒葛后皮炎的发生，但肥皂更有效。lawsone 的含量与预防 PI 皮疹无关。也许皂苷，即凤仙花的肥皂成分是有效成分。
