Natural Toxicants in Human Foods: Psoralens in Raw and Cooked Parsnip Root

Abstract

Parsnip root contains three photoactive, mutagenic, and photocarcinogenic psoralens in a total concentration of about 40 parts per million. These chemicals are not destroyed by normal cooking procedures (boiling or microwave); thus humans are exposed to appreciable levels of psoralens through the consumption of parsnip and possibly other psoralen-containing foodstuffs. The toxicologic consequences to man of such exposure may be speculated on the basis of medicinal and laboratory studies, but epidemiologic data are not available.

Dietary pesticides (99.99% all natural).

“…[10][11][12][13] and the following: 5-methoxypsoralen (light-activated) and 8-methoxypsoralen (46, 47) (psoralen, which is carcinogenic by skin painting, and many other mutagenic psoralen derivatives are also present in parsley and celery); p-hydrazinobenzoate and glutamyl p-hydrazinobenzoate (48,49); allyl isothiocyanate (31,32); D-limonene (50); estragole and safrole (45,51); ethyl acrylate and benzyl acetate (52); a-methylbenzyl alcohol (53); caffeic acid (37); sesamol (37); catechol (37). Concentration references are as follows: 5-and 8-methoxypsoralen (17,(55)(56)(57)(58)(59); p-hydrazinobenzoates (in commercial mushrooms) (48,49); sinigrin (38)(39)(40)60); D-limonene (61-63); estragole and safrole (64-67); ethyl acrylate (68); benzyl acetate (69-71), a-methylbenzyl alcohol (23); caffeic acid, chlorogenic acid, and neochlorogenic acid (72)(73)(74)(75)(76)(77)(78)(79)(80) [in coffee (81)]; catechol (83,84); sesamol (85). For mutagenicity and clastogenicity references, see text.…”

The Biology of Canadian weeds. 144. Pastinaca sativa L.

“…Significant harm is caused by the toxic compounds present in wild and cultivated forms (see Section 7c), causing both photo-activated dermatitis and toxicity in the absence of light (Scott et al 1976;Mitchell and Rook 1979;Ivie et al 1981;Søborg et al 1996). The principal toxic compounds, furanocoumarins (furocoumarins), are found in P. sativa, some other species in the Umbelliferae and about seven other plant families (Scott et al 1976;Murray et al 1982;Berenbaum 1981bBerenbaum , 1983Knudsen and Kroon 1988;Burrows and Tyrl 2001).…”

“…The phototoxic activity of parsnip extracts is resistant to breakdown by heating (e.g., autoclaving, cooking, etc.) or storage of several months (Jensen and Hansen 1939;Ivie et al 1981;Beier 1990;Ostertag et al 2002).…”

“…Adduction to and oxidation of (with or without accompanying UV irradiation) nucleic acids, protein, and lipids by various furanocoumarins are also mechanisms involved in cell damage (Scott et al 1976;Ivie et al 1981;Murray et al 1982;Berakha and Lefkovits 1985;Lowe 1986;Berenbaum and Larson 1988;. The lesions caused by contact with furanocoumarin-bearing plants followed by UV-A irradiation are usually referred to as photodermatitis or phytophotodermatitis.…”

“…Because of the effect on skin pigmentation (hyperpigmentation), furanocoumarins traditionally gathered from plant sources have been used extensively in the treatment of vitiligo (leukoderma), and in the preparation of ''sun-tan'' lotions, as well as for the treatment of psoriasis (Pathak et al 1962;Scott et al 1976; Van Scott 1976;Ivie et al 1981;Søborg et al 1996;Beier and Nigg 2001). Furanocoumarins have also been found to have potential as insect repellents, as they suppress feeding and growth in some insect species (Klocke et al 1989), and have been investigated for anti-bacterial and anti-fungal properties (Johnson et al 1973;Fischer et al 1976;Wolski et al 2000Wolski et al , 2004.…”