Antipruritic and antidermatitic effect of extract and compounds of Impatiens balsamina L. in atopic dermatitis model NC mice.

We examined the effects of a 35% ethanol extract (IB) from the petals of Impatiens balsamina L. and the principal active compounds from IB on chronic and serious pruritus and the development of dermatitis using NC mice, a model of atopic dermatitis. IB at 100 mg/kg significantly inhibited serious scratching behaviour in the NC mouse with established dermatitis when administered i.v. 1 h before, or p.o. 24 h before the measurement. A 10 microg/kg dose of kaempferol 3-rutinoside and 2-hydroxy-1,4-naphthoquinone (lawsone) isolated from IB also inhibited scratching behaviour in the NC mouse with established dermatitis. When 4-week-old NC mice with no symptoms were administered orally 100 mg/kg/day of IB until 13 weeks of age, protection was also noted against scratching behaviour during the development of dermatitis. IB was effective for the prevention and treatment of atopic dermatitis. Copyright 2001 John Wiley & Sons, Ltd.