Allergic and Atopic Reactions

Summary

Herbs with Allergic and Atopic Potential

Allergic reactions to plants are common, as evidenced by seasonal allergies to airborne pollen, spores and seeds. Despite the theoretical possibility that any plant, plant part, or plant extract may cause an allergic reaction in a susceptible individual (idiosyncratic reaction), the occurrence of life threatening anaphylaxis and bronchospasm from medicinal plants is in fact extremely rare.

Sesquiterpene lactones.
• mechanism: Contact dermatitis, and rarely other forms of hypersensitivity, to plants from the Asteraceae (Daisy) family is well documented. The compounds responsible are sesquiterpene lactones (SL's) of which over 3000 have been described, mostly in the Asteraceae but also in the Apiaceae (Parsley) family. SL's have numerous important pharmacological properties, which may include anti-inflammatory, antimicrobial, antifungal, antihelminthic, hypolipidemic and cardiotonic activities. Contact dermatitis to SL's can exhibit cross-reactivity among different species. Sensitized individuals should avoid all contact with Asteraceae species. Oral ingestion of SL's in medicinal plant extracts is not commonly associated with allergic reaction. SL's are responsible for the reported allergenicity of Tanacetum (Feverfew) and Matricaria (Chamomile) plant material.

Ranunculosides.
• mechanism: Handling fresh plant material from certain genera of the Ranunculaceae (Buttercup) family may cause exposure to sap which contains irritant, toxic lactones, notably protoanemonine. Fortunately, this compound is unstable and its degradation products are non-irritant. Exposure to fresh protoanemonine may cause muco-cutaneous vesiculation, and severe gastric irritation if ingested.

less common potential allergenic herbs:

• reports: Various other plant constituents, including volatile oils and resins, have been reported to cause allergic responses. Notable reports concern Cinnamomum spp. (Cinnamon), Propolis (not strictly a plant), Populus candicans (Balm of Gilead), Tilia spp. (Linden Flower) and Commiphora (Myrrh).
(Bone K, 1996.)



Herbs

Sesquiterpene lactone-containing herbs (Asteraceae) with high allergenic potential:
• Arnica cordifolia (Heartleaf Arnica)
• Arnica latifolia (Broadleaf Arnica)
• Arnica longifolia (Longleaf Arnica)
• Arnica montana (Arnica)
• Inula helenium (Elecampane)
• Laurus nobilis (Laurel - fam. Lauraceae)
• Tanacetum cinerariifolium (Pyrethrum)
• Tanacetum parthenium (Feverfew)

Sesquiterpene lactone-containing herbs (Asteraceae) with low or moderate allergenic potential:
• Cichorium intybus (Chicory)
• Cnicus benedictus (Blessed Thistle)
• Cynara scolymus (Artichoke)
• Helianthus annuus (Sunflower)
• Lactuca virosa (Wild Lettuce)
• Matricaria recutita (German Chamomile)
• Saussurea lappa (Costus Root)
• Taraxacum officinale (Dandelion)

Protoanemonine forming herbs (Ranunculaceae):
• Anemone nemorosa (Wood Anemone)
• Calatha palustris (Marsh Marigold)
• Helleborus niger (Black Heelbore)
• Pulsatilla vulgaris (Pasque flower)
• Ranunculus acris (Field Buttercup)
• Trollius europaeus (Globe Flower)

(Adapted from De Smet PAGM, et al., 1992; Hoffmann D. 1999; Brinker F. 1998).

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Do not rely solely on the information in this article.

The information presented in Interactions is for informational and educational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, case reports, and/or traditional usage with sources as cited in each topic. The results reported may not necessarily occur in all individuals and different individuals with the same medical conditions with the same symptoms will often require differing treatments. For many of the conditions discussed, treatment with conventional medical therapies, including prescription drugs or over-the-counter medications, is also available. Consult your physician, an appropriately trained healthcare practitioner, and/or pharmacist for any health concern or medical problem before using any herbal products or nutritional supplements or before making any changes in prescribed medications and/or before attempting to independently treat a medical condition using supplements, herbs, remedies, or other forms of self-care.


References

Bone K. Safety of Herbal Medicines. Melbourne Australia: MediHerb Seminar, 1996.

Brinker F. Herb Contraindications and Drug Interactions. Second edition. Sandy, OR: Eclectic Institute Inc, 1998.

DeSmet PAGM, et al.(eds.) Adverse Effects of Herbal Drugs 2. NY: Springer Verlag, 1993.

Hoffmann D. Phytochemistry. (Forthcoming title, in press 1999, publisher to be confirmed).