Atopic dermatitis, allergic rhinitis, food allergy and asthma are classified as type I allergy. Atopic dermatitis is a common disorder in the population, and recent studies have shown that the disease is increasing, its prevalence increasing by 2-to 3-fold during the past three decades in industrialized countries, 1) and the reported prevalence among children up to the age of 16 ranges between 15% and 30% in Europe.
2)Atopic dermatitis is a condition manifesting eczema, serous papules, scaling and crust and in severe cases, erosion of the affected skin. Itching, a sensation causing the urge to scratch, is the most significant outcome of atopic dermatitis. This unpleasant sensation stimulates scratching of the lesioned skin, thus worsening the lesions.3) In the treatment of atopic dermatitis, anti-histamine and anti-allergy drugs are generally used, but they do not allay a severe itching sensation in atopic dermatitis. 4,5) Corticosteroid is also used as external medicine to relieve cutaneous pruritics, but it has many adverse effects including skin atrophy, rosacea, acne, purpura and so on 6) ; therefore, it is worth developing new treatment drugs besides the generally used medicines.Traditional Chinese medicines have a long history dating back several thousands of years. There are many herb medicines which have been applied to cutaneous disease and some traditional Chinese herbal medicines are prescribed for dermatitis.7) Among these, Moutan Cortex, the root bark of Paeonia suffruticosa ANDREWS, is a widely used drug for cutaneous disease in traditional Chinese medicine. 8,9) In association with this, Moutan Cortex is effective in cardiovascular and female genital disease. 10,11) In addition, Moutan Cortex has been described to show analgesic, sedative, antiinflammatory and antimicrobial properties 12) ; however, we have as yet very little information as to whether Moutan Cortex is effective in experimental allergy models.In the present study, therefore, we demonstrated the inhibitory effects of ethanol extract from Moutan Cortex on experimental immediate allergic reactions both in vitro and in vivo.
MATERIALS AND METHODS
AnimalsFemale ICR mice (6-10 weeks old) and male Wistar rats (7 weeks old) were obtained from Japan SLC, Inc., Shizuoka, Japan. The animals were housed in an airconditioned room maintained at 24Ϯ2°C with a relative humidity of 55Ϯ15%. They were given standard laboratory rodent food chow (Oriental Yeast, Tokyo) and water ad libitum. All procedures involving animals were conducted in accordance with the Guidelines for Animal Experiments at Okayama University Advanced Science Research Center.
Chemicals and ReagentsThe following reagents were used in this study and their sources are shown in parentheses: histamine dihydrochloride (Sigma, St. Louis, MO, U.S.A.), compound 48/80 (Sigma) and Evans blue (Wako, Tokyo, Japan). Compound 48/80 and histamine were dissolved in physiological saline and administered intradermally. The drugs used were azelastine hydrochloride (Sigma), ketotifen fumarate (Sigma)...
