EFFECT OF EXTRACTS OF ANGELICA POLYMORPHA ON REAGINIC ANTIBODY PRODUCTION CHENG-PO SUNG,ALANP. BAKER,DAVIDA. HOLDEN, WILLIAMJ. SMITH and LAWRENCE W. C H A K R I N ~ Department of Pharmacology, Smith Kline and French Laboratories, P . 0 . Box 7929, Philadelphia, Pennsylvania 19101
A B S T R A U C ~ aqueous .-~ extract of Angelica polymorpha was examined for its immunoregulating properties. I t s effect on the production of antibodies was tested in (C57BL/6 x DBA/B)FI mice. When the animals were treated daily with the extract, the serum titers of reaginic antibodies normally observed after a single injection dinitrophenylovalbumin (DNP,-OA) were significantly lower, and the higher and more sustained reaginic titers induced by booster injections of D N P s O A were also inhibited. The immunosuppressive activity was observed both by oral and intraperitoneal administration of the extract, and it was not removed by dialysis. I n contrast, the serum titers of IgG were not significantly altered by the administration of the extract. The extract had little or no effect on the passive cutaneous anaphylaxis reaction or the release of histamine from sensitized rat lung fragments.
Those conditions in which individuals are sensitive to a variety of environmental substances are called atopy and include hayfever, asthma and atopic dermatitis. These conditions are associated with antibodies of the IgE class, and sera of atopic patients contain IgE levels that are often 3 to 10 times greater than the upper limit found in normal human sera, which is in the range of 0.1-0.4 pg/ml. These antibodies have a high affinity for receptors on mast cells and basophilic leukocytes. The affinity of IgE for these cells apparently derives from sites in the Fc domain, leaving the two antigen binding sites at the Fab terminal free to react with the antigen. When antigen molecules combine with the IgE antibodies on these target cells, a cascade of intracellular metabolic processes is triggered, resulting in the synthesis and release of mediators which include histamine, slow-reacting substance, eosinophil chemotactic factor, and platelet-activating factor. When these mediators are released in sufficient quantities the clinical syndromes of atopy, consisting of bronchoconstriction, edema, increased secretion of mucus and vascular collapse, are manifested (1,2). In view of the crucial role which IgE plays in atopic diseases, it seems likely that prevention or suppression of IgE antibody formation would be beneficial for atopic patients. In a search for this pharmacological action, we included the evaluation of extracts of natural products. Roots of Angelica polymorpha var. sinensis diels (known as “Tang-Kuei” in Chinese), an aromatic herb belonging to the Umbelliferae family, have long been used in Chinese medicine. The material is taken in the form of a decoction for R variety of disorders such as dysmenorrhea, metrorrhagia, rheumatism, ulcers, and anemia. I t is said to be antispasmodic, analgesic, sedative, anti-inflammatory and a remedy for disorders of the respiratory system and blood circulation (3,4). Although it has not been clearly reported, “Tang-Iiuei” has been used for the prevention and relief of allergic symptoms and, in some cases, asthmatic attacks. The aqueous extract of Angelica polymorpha roots was therefore studied for its effect on IgE antibody production and anaphylactic reactions. RESULTS AND DISCUSSION The ability of the aqueous extract of Angelica polymorpha to affect reaginic antibody production was determined by administration of the extract to (C57BL/6 X DBA/2)F1 mice appropriately immunized with D K P 3 4 A . Initially, it was tested for its potential to alter the primary reaginic response. In this system ‘Present address: Sterling-Winthrop Research Institute, Rensselaer, New York 12144. 398
Jul-Aug 19821 Sung et al.:
Effect on Reaginic Antibody Production
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the mice were injected intraperitoneally with 1 pg of DNP,-OA in the presence of 0.05 ml alhydrogel in 0.5 ml saline. The immunological response was followed by measuring serum reaginic titers and the immunocompetence of the splenocytes. Figure 1 shows that serum reaginic titers and the ability of the splenocytes to produce reaginic antibodies were maximal on Day 11 as measured by heterologous passive cutaneous anaphylaxis and adoptive cutaneous and anaphylaxis, respectively. The results presented in figure 1 are for a 1/80 dilution of serum and a concentration of 2x106 cells per site of injection. At these concentrations no detectable wheals were observed on Day 21 or thereafter. However, positive reactions were obtained for the later days if the sera were not diluted as much and greater numbers of cells were injected per site.
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10 20 Days after immunization FIG.1. The induction of reaginic antibodies in mice by a single intraperitoneal injection of 1 pg DNPs-OA. Serum reaginic antibodies were measured by heterologous passive cutaneous anaphylaxis; the sera were diluted 1/80. The immunocompetence of the splenocytes was determined by heterologous adoptive cutaneous anaphylaxis: 2x lo6 cells were injected per site.
To test the effect of extracts of Angelica on this primary response, the mice were given the extract prior to immunizing on Day 0 with DNP3-OA. Dosing was continued through Day 10 excluding the weekend (Days 5 and 6). A control group received the vehicle on days of scheduled test dosing. On Day 11, the mice were exsanguinated, and serum and/or splenic cells were evaluated in the rat for their IgE levels and IgEsynthetic capability, respectively. Donor mouse sera or spleens were pooled within each test/control group for the evaluation. The results in table 1 show that the intraperitoneal administration of dilutions of the original extract up to 1:160 completely or nearly completely suppressed the serum titer of IgE. Immunosuppressive activity was also observed when the extract was orally administered (table 2). In these studies, the serum titer of IgE was monitored,
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TABLE 1. The effect of intraperitoneal administration of an extract of AngeQca p o l y m o r p h on the production of reaginic antibody formation in the m o m . HPCA Reaction Dilution of Extract
Comparison a t 1/20 dilution of serum Titer-b
Saline Control 1/3. . . . . . . . . . . 1/5. . . . . . . . . . . . . . . . . 1/10. . . . . . . . . . . . . . . . 1/20. . . . . . . . . . . . . . . . 1/40. . . . . . . . 1/80.. . . . . . . 1/160. . . . . . . . . . . . . . . 1/320. . . . . . . . . . . . . . . 1/640. . . . . . . . . . . . . . .
1
80
