Allergic and irritant contact dermatitis from falcarinol and didehydrofalcarinol in common ivy (Hedera helix L.)

Abstract

Experimental and chemical investigations revealed that common ivy (Hedera helix susp. helix) contains 3 compounds which are powerful irritants and moderate sensitizers. Only 2 of these constituents, falcarinol and didehydrofalcarinol, are present in the plant during the whole year. Besides Panax ginseng and Schefflera arboricola, this is the third species of the Araliaceae in which these polyacetylenic sensitizers have been found. Falcarinol and didehydrofalcarinol also occur in Hedera helix subsp. canariensis. 4 patients have been patch tested. Even in low concentrations (0.03%), the main allergen falcarinol elicited strong reactions in all of them. One of the authors became sensitized during the investigations.

Acetylenes and Psoralens

“…The relation between the clinical effect and the content of polyacetylenes has been investigated in Schefflera arboricola (Hayata) Merrill (Araliaceae) (dwarf umbrella tree), and the results showed that falcarinol (1) is a potent contact allergen, whereas related polyacetylenes such as falcarindiol (2) and falcarinone (4) had no effect on the skin . Falcarinol has been shown to be responsible for most of the allergic skin reactions caused by plants of the Apiaceae and Araliaceae (Hausen et al 1987;Hausen 1988;Murdoch and Demster 2000;Machado et al 2002). The allergenic properties of falcarinol indicate that it is very reactive towards mercapto and amino groups in proteins, forming a hapten-protein complex (antigen) (Figure 5.12).…”

Open Trial to Assess Aspects of Safety and Efficacy of a Combined Herbal Cough Syrup with Ivy and Thyme

“…Allergic and irritant contact dermatitis caused by contact with ivy plants may occur. Polyacetylenes (falcarinol and didehydrofalcarinol) were identified as allergenic substances [12]. However, there are some theoretical concerns with regard to ivy leaves because of their saponin content.…”

Plants and Plant Products

“…It contains three powerful irritants and weak sensitizers, namely didehydrofalcarinol and falcarinol (Fig. 31) that have mod- erate sensitizing potentials [310,362,363]. These allergens or related molecules are also present in other members of this family, such as ginseng (Panax ginseng C. Meyer), Schefflera arboricola Hayata [310] or kakuremino (Dendropanax trifidus Makino) [364].…”

“…Falcarinol, also contained in members of Araliaceae (see later section), is probably the delayed-type allergen present [309,310].…”

“…31) that have mod- erate sensitizing potentials [310,362,363]. These allergens or related molecules are also present in other members of this family, such as ginseng (Panax ginseng C. Meyer), Schefflera arboricola Hayata [310] or kakuremino (Dendropanax trifidus Makino) [364]. Falcarinone, an oxidation product of falcarinol, is commonly found in the Apiaceae/Umbelliferae family [310], and falcarinol is likely a delayed-type allergen of Apiaceae/Umbelliferae, as in carrot, celery, and parsley [309,310].…”