Unusual contact allergens from plants in the family Hydrophyllaceae

  title={Unusual contact allergens from plants in the family Hydrophyllaceae},
  author={Gary W. Reynolds and William L. Epstein and Eloy Rodr{\'i}guez},
  journal={Contact Dermatitis},
The dermatitic constituents of the glandular hairs of plants in the family Hydrophyllaceae comprise a class of uncommon natural products called “phacelioids”. The chemical structures consist of various elaborations of hydroquinone attached to a C10 to C20 prenyl chain. Certain of these compounds are equivalent to the urushiols of Toxicadendron (Rhus) in their capacity to sensitize humans. Although structurally related to the urushiols, the phacelioids do not appear to cross‐react in humans… 
Contact allergens of an urban shrub Wigandia caracasana
The principal dermatitic constituents of W. caracasana were isolated from the glandular hairs and identified as unusual prenylated quinones and prenylated phenols. Potentials to elicit irritant and
Guinea pig maximization test of the bark extract from pawpaw, Asimina triloba (Annonaceae)
The potential of Fraction F020 (a pesticidal crude extract of pawpaw stem bark) to sensitize and elicit an allergic contact dermatitis response was determined by using a modified guinea pig maximization test (GPMT).
AISLAMIENTO E IDENTIFICACIÓN DE METABOLITOS SECUNDARIOS PRESENTES EN HOJAS DE Wigandia urens (Hydrophyllaceae) Isolation and identification of secondary metabolites in leaves from Wigandia urens (Hydrophyllaceae)
Two compounds dont know in the plant were isolated, flavidulol A and geranylhydroquinone, a previously isolated benzociclodecadiene from a fungus and a prenylated hydroquinone reported in other genera of the same family.
Distribution, Ecology, Chemistry and Toxicology of Plant Stinging Hairs
The physiological effects of stinging hairs on humans vary widely between stinging plants and range from a slight itch, skin rash, and oedema to sharp pain and even serious neurological disorders such as neuropathy.
Structure‐activity relationships in allergic contact dermatitis
The results showed an increase of the sensitizing capacity with increasing length of the alkyl side chain from C1 to C10, reaching a maximum at C11 and C12, and on further elongation the senstizing potency decreased beyond C13 reaching values which finally were as low as those of the C1 and C3 derivatives.
Miscellaneous dermatitis-inducing plants.
Plants and Plant Products
Contact dermatitis from plants or plant products may occur by several mechanisms and reactions of mixed aetiology, for instance irritant reactions superimposed on allergic reactions, are often seen, while mechanical plus chemical irritant effects are evoked by, for example, stinging nettles.
Stinging Trichomes in Apocynaceae and Their Evolution in Angiosperms
The glandular trichomes in Fischeria and Matelea can indeed be classified as stinging, and Apocynaceae is the seventh family for which this type of trichome has been reported.
Plant-induced dermatitis.
  • W. Epstein
  • Medicine
    Annals of emergency medicine
  • 1987
Experiences with Freund's complete adjuvant test (FCAT) when screening for contact allergens in colophony
The FCAT method was found to be advantageous over the GPMT method in that it is technically simpler to use and a smaller amount of test substance is needed, however, closed challenge was preferred to the prescribed open challenge.


A potent contact allergen of Phacelia (Hydrophyllaceae)
Comparative patch testing on humans with urushiol established that the Phacelia allergen does not cross‐react with poison oak or ivy.
Prenylated Phenolics that Cause Contact Dermatitis from Glandular Trichomes of Turricula parryi.
The principal phenolic constituents were isolated from the exudate of the glandular trichomes of TURRICULA PARRYI, a California shrub that causes severe contact dermatitis, and the principal agents of dermatitis were the farnesyihydroquinone derivatives 3 and 6.
Prenylated phenols that cause contact dermatitis from trichomes of Phacelia ixodes.
The principal phenolic constituents were isolated from the exudate of the glandular trichomes of PHACELIA IXODES K ELLOGG (Hydrophyllaceae), a Mexican plant that causes allergic contact dermatitis.
Dermatitis venenata from Phacelia crenulata.
Shortly after one of us (S. I. S.) started practicing dermatology in Tucson, Ariz., in 1949, he noticed that every few years, in the spring, there was quite a number of cases of dermatitis venenata
Dermatitis venata from Phacelia crenulata
  • Archives of Dermatology
  • 1962
Dermatitis produced by Phacelia
  • Science
  • 1932