Prenylated Phenols that Cause Contact Dermatitis from Trichomes ofPhacelia ixodes

Publisher Website
Google Scholar
Abstract
The principal phenolic constituents were isolated from the exudate of the glandular trichomes of Phacelia ixodes KELLOGG (Hydrophyllaceae), a Mexican plant that causes allergic contact dermatitis. These are, in decreasing order of the amount in the trichomes: geranylhydroquinone (I), 3-geranyl-2,5-dihydroxyphenyl acetate (II), geranylbenzoquinone (III), 2-geranyl-6-hydroxy-4-methoxyphenyl acetate (IV), 2-geranyl-4-hydroxyphenyl acetate (V), 6-hydroxy-2-methyl-2-(4-methyl-3-pentenyl)-chromene (VI), and 6,7-dimethoxyapigenin. Compounds II, IV, and V are new natural products. Geranylbenzoquinone was the principal contact allergen in testing with guinea pigs.