Contact allergy to parthenolide in Tanacetum parthenium (L.) Schulz-Bip. (feverfew, Asteraceae) and cross-reactions to related sesquiterpene lactone containing Compositae species.

A case of specific, delayed hypersensitivity induced by repeated contact with a wild form of feverfew (Tanacetum parthenium) is reported. In the flowers investigated the content of the responsible contact allergen parthenolide--a potent sesquiterpene lactone--appeared to be 10 times greater (0.6-0.9%) than in earlier years. Guinea pig experiments confirm the strong sensitizing potency of this Compositae species. Cross-reactions were elicited with 11 of 21 mostly Compositae plants containing chemically related sesquiterpene lactones. The strongest reactions were elicited by tansy, yarrow (milfoil), marguerite, aster, sunflower, laurel and Frullania. Structure elucidation by X-ray crystallographic analysis established the precise molecule configuration of parthenolide, although the lattice parameters of the isolated compound were not in accordance with those published in the literature.