CUPRESSACEAE

(Cypress family)

The 130 species of principally evergreen coniferous trees and shrubs in 19 genera are of cosmopolitan distribution.

Several species provide useful timber, including the incense cedar (Calocedrus decurrens Florin), Lawson's cypress (Chamaecyparis lawsoniana Parl.), the Monterey cypress (Cupressus macrocarpa Hartw.), alerce (Tetraclinis articulata Masters), and the red cedar (Juniperus virginiana L.). The incense cedar and red cedar are both used to make pencils.

The fruit of the common juniper (Juniperus communis L.) is used for flavouring gin; oil of cade, which is used in dermatological preparations, is produced by the destructive distillation of prickly juniper wood (Juniperus oxycedrus L.); savin oil is produced from Juniperus sabina L.; sandarac resin, which was formerly used as a pill varnish, is derived from Tetraclinis articulata Masters.

Generally, timbers derived from members of this family should be regarded as potentially hazardous to the skin. Quinones such as thymoquinone, and tropolones such as β- and γ-thujaplicin appear to be the principal contact allergens, but podophyllotoxin and other dermatologically active compounds have also been found in members of the family. Foliage, too, may be responsible for contact dermatitis. Occupational asthma may occur in woodworkers.

Austrocedrus chilensis Pic.Serm. & Bizzarri

[syns Libocedrus chilensis (D.Don) Endl., Thuya chilensis D.Don]

Chilean Incense Cedar

Fitzgerald et al. (1957) reported the presence of desoxypodophyllotoxin in the leaves of this species. See also Podophyllum peltatum L. (fam. Podophyllaceae).

Callitris Vent.

Cypress Pine

According to Maiden (1921a), an itch can occur in those cutting Callitris whilst the trees are laden with pollen. Cleland (1925) also refers to this report.

The timber of commerce comes mainly from Callitris glauca R.Br. (Boas 1947).

Callitris columellaris F.Muell.

[syns Callitris glauca R.Br. ex R.T.Baker & H.G.Sm., Callitris glaucophylla Joy Thomps. & L.A.S.Johnson, Callitris intratropica R.T.Baker & H.G.Sm.]

Bribie Island Pine, Coast Cypress-Pine, Murray River Pine, Northern Cypress Pine, Sand Cypress, Western Sand Cypress, White Cypress-Pine

Aynehchi (1971) reported the presence of desoxypodophyllotoxin, otherwise known as silicicolin, in the leaves and stems of this species (see also Podophyllum L., fam. Podophyllaceae). Brecknell & Carman (1978, 1979) found several sesquiterpene lactones including columellarin, a potentially allergenic guaianolide (see also Compositae), in the heartwood.

Calocedrus decurrens Florin

[syns Libocedrus decurrens Torr., Heyderia decurrens K.Koch, Thuja decurrens Voss]

Californian White Cedar, Incense Cedar

This species yields valuable timber. Incense cedar and Virginian pencil cedar (probably Juniperus virginiana L.) are both officially recognised causes of dermatitis in the German pencil industry (Koelsch 1931).

Calnan (1972) described cases of dermatitis from cedar wood pencils: a male carpenter and floor layer developed dermatitis affecting the groins, buttocks, thighs, legs, and feet. From time to time he developed patches of an exudative dermatitis behind his ear which he attributed to holding a pencil there. The dermatitis on his feet followed a period of work sawing wood. Patch tests were positive to the wood of a pencil. In the case of a female clerk, aged 48 year, dermatitis affecting the right hand and middle and ring fingers was reported. Patch tests were positive to the wood of her pencil. In the case of the carpenter, patch tests were positive to ethereal, aqueous, and ethanolic extracts of the heartwood of Libocedrus decurrens. In both cases, patch tests were positive to thymoquinone and thymoquinol and, in the case of the clerk, to carvacrol. These compounds are known to occur in the heartwood (Zavarin & Anderson 1955a, Anderson et al. 1963).

Other dermatologically active compounds have also been found in the heartwood, including γ-thujaplicin (Zavarin & Anderson 1955b, 1956, Anderson et al. 1963) which was studied by Bleumink et al. (1973b) in a case of western red cedar [see Thuja plicata Donn ex D.Don below] allergy, and β-thujaplicin (Zavarin & Anderson 1956), the contact allergenic properties of which were studied by Ito (1964). In addition, the cytotoxic lignan desoxypodophyllotoxin has been isolated from the leaves and stems (Kupchan et al. 1967) — see Podophyllum L., fam. Podophyllaceae.

Chamaecyparis lawsoniana Parl.

[syn. Cupressus lawsoniana Andr. Murray]

Lawson Cypress, Port Orford Cedar

Prosser White (1934) noted that healing was troublesome and prolonged if a spicule [= ?] entered the skin.

Several authors report that the foliage of this tree can produce dermatitis, and the wood can cause asthma in wood-workers (Rasch 1923/24, Schonwald 1929, Stier 1929, Hausen 1970). Woods & Calnan (1976), however, found that none of the literature cited by Hausen (1970) provided convincing evidence for contact dermatitis.

The powerful resinous odour of the newly-cut wood was said to cause troublesome diuresis in saw mill workers (Sargent 1896). The pollen can cause pollinosis (Wodehouse 1971).

Fitzgerald et al. (1957) reported the presence of desoxypodophyllotoxin in the leaves of this species. Only traces of β-thujaplicin and no other tropolones have been found in the heartwood (Zavarin & Anderson 1956, Zavarin et al. 1959).

Chamaecyparis nootkatensis Spach

[syns Chamaecyparis nutkaënsis Lindl. & Gordon, Chamaecyparis nootkaënsis Carrière]

Nootka Cypress, Alaska Cedar, Alaska Yellow Cedar

This species yields carvacrol (Watt & Breyer-Brandwijk 1962), one of the elicitors of Calocedrus decurrens allergy. No thujaplicins could be detected (Zavarin & Anderson 1956).

Chamaecyparis obtusa Siebold & Zucc.

[syns Thuya obtusa Masters, Cupressus obtusa K.Koch]

Hinoki Cypress, Japanese False Cypress

This species, known locally in Japan as chyabohiba, was found to contain sesamin (Masumura 1955). Sesamin is known for its role in sesame oil (Sesamum indicum L., fam. Pedaliaceae) dermatitis.

Chamaecyparis taiwanensis Masam. & Suzuki

The presence of β-thujaplicin has been reported in this species (Zavarin et al. 1959). The contact allergenic properties of this compound were investigated by Ito (1964).

Chamaecyparis thyoides Britton, Sterns, & Pogg.

[syn. Cupressus thyoides L.]

Atlantic White Cedar, White Cypress

Zavarin & Anderson (1956) and Zavarin et al. (1959) reported the presence of tropolones, including β- and γ-thujaplicin, in the heartwood of this species. Enzell (1960), on the other hand, could not detect any tropolones in their material. The role of γ-thujaplicin in western red cedar [see Thuja plicata Donn ex D.Don below] allergy was investigated by Bleumink et al. (1973b). The contact allergenic properties of β-thujaplicin were demonstrated by Ito (1964).

Cunninghamia lanceolata (Lamb.) Hook.

[syns Cunninghamia chinensis de Vos, Cunninghamia sinensis R.Br., Pinus lanceolata Lamb.]

China Fir, Chinese Cedar, Chinese Fir, Spießtanne

In a text on Chinese materia medica, Stuart (1911) noted that a decoction of the wood of Cunninghamia sinensis is a remedy for varnish poisoning (Rhus vernicifera) and is used for bathing foetid feet. He noted also that the ash of the old bark is applied to wounds, scalds, and burns.

x Cupressocyparis leylandii Dallimore

[syn. Cupressus leylandii A.B. Jackson & Dallimore]

Leyland Cypress

A male aged 40 years, who was contact sensitive to zinc oxide plaster containing colophony, developed dermatitis from planting this species (Hindson et al. 1982).

Cupressus L.

This is a genus of between 15 and 20 species found in the region of the Mediterranean, the Sahara, Asia, and North America.

β-Thujaplicin, the contact allergenic properties of which have been investigated by Ito (1964), has been found in the majority of species (Zavarin et al. 1967, Zavarin et al. 1959), including:

Cupressus abramsiana C. Wolf

Cupressus arizonica Greene

Cupressus bakeri Jepson subsp. typica Wolf

Cupressus bakeri Jepson subsp. matthewsii Wolf

Cupressus benthami Endl.

Cupressus forbesii Jepson

Cupressus formosensis Henry

[syn. Chamaecyparis formosensis Matsum.]

Cupressus funebris Endl.

Cupressus glabra Sudw.

Cupressus goveniana Gordon

Cupressus guadalupensis Watson

Cupressus lindleyi Klotzsch

Cupressus lusitanica Mill.

Cupressus macnabiana Andr. Murray

Cupressus macrocarpa Hartw.

Cupressus nevadensis Abrams

Cupressus pygmaea Sargent

Cupressus sargentii Jepson 

Both γ-thujaplicin and β-thujaplicinol, which have been found to be elicitors of Thuja plicata dermatitis (Bleumink 1973b), have been demonstrated to occur in the heartwood of the following species (Zavarin et al. 1967):

Cupressus arizonica Greene

Cupressus forbesii Jepson

Cupressus glabra Sudw.

Cupressus guadalupensis Watson

Cupressus lusitanica Mill. 

In addition, β-thujaplicinol, but not γ-thujaplicin, has been detected in:

Cupressus benthami Endl.

Cupressus macnabiana Andr. Murray

Cupressus sargentii Jepson 

Cupressus sempervirens L.

Cypress, Italian Cypress, Funeral Cypress

This species is a native of Greece and Crete, but is commonly planted for ornament in the Mediterranean region.

The wood can cause dermatitis (Hausen 1970). The presence of β-thujaplicin and carvacrol in the heartwood of this species was reported by Enzell & Erdtman (1957). See Calocedrus decurrens Florin and Thuja plicata Donn ex D.Don.

A man who was contact sensitive to Dalbergia L.f. (fam. Leguminosae) showed transient erythema from a patch test with cypress wood (Lewith 1929).

The pungent smell of cypress wood causes headaches in carpenters (Ramazzini 1713).

Cupressus sempervirens L. var. stricta Aiton

Columnar Italian Cypress

Cypress oil, a fragrance raw material derived from this taxon by steam distillation of the leaves, was found to be moderately irritating to rabbit skin when applied under occlusion for 24 hours. At a dilution of 5% in petrolatum, it was found to be non-irritant to human skin in a 48 hour closed patch test. No sensitising nor phototoxic effects could be demonstrated (Opdyke 1978, p. 699).

Zavarin et al. (1967) reported the presence of β-thujaplicin in the heartwood. The contact allergenicity of this compound has been demonstrated on guinea pigs (Ito 1964).

Fitzroya cupressoides (Molina) I.M.Johnst.

[syns Pinus cupressoides Molina, Fitzroya patagonica Hook.f. ex Lindl.]

Alerce, Patagonian Cypress

Those who work with the wood may experience irritation of the respiratory tract (Orsler 1973) and allergic contact dermatitis (Oleffe et al. 1974, Oleffe et al. 1975a, Oleffe et al. 1975b, Oleffe et al. 1975c).

The genus Fitzroya Hook.f. ex Lindl. is now considered to be monotypic. The tree grows naturally in southern Argentina and southern Chile (Mabberley 1997).

Juniperus L.

Some 60 species are found in the Northern Hemisphere.

A commercially available Juniperus extract (Hollister-Stier Laboratories) frequently (14/26) produced irritant patch test reactions (Mathias et al. 1979).

The leaves of some species can cause punctate erythema or linear papules on the hands, wrists, forearms, and ankles of persons who weed or work amongst juniper shrubs. The reaction seems to be a mechanical effect, but an eczematous reaction sometimes observed may be a reaction from self-medication. Patch tests produced equivocal or negative results (Mitchell JC — unpublished observation).

Hjorth (1968) recorded a positive patch test reaction to juniper. Juniper wood can produce dermatitis and respiratory symptoms in wood-workers (Orsler 1973).

Juniper, either smoked or used in tea, can produce euphoric, stimulant, or hallucinogenic effects (Anon 1979).

β-Thujaplicin, the contact allergenic properties of which were investigated by Ito (1964), has been detected in trace amounts in the heartwood of some species (Zavarin et al. 1959), including:

Juniperus deppeana Steud.

Juniperus monosperma Sargent

Juniperus osteosperma Little

[syn. Juniperus tetragona Schlechter var. osteosperma Torr.] 

See also Calocedrus decurrens Florin above.

Juniperus cedrus L.

A phytochemical investigation of the heartwood demonstrated the presence of thymoquinone, carvacrol, and β-thujaplicin (Runeberg 1960a). Positive patch test reactions to both of these compounds have been observed (see Calocedrus decurrens Florin and Thuja plicata Donn ex D.Don).

Juniperus chinensis L.

Chinese Juniper

Carvacrol, β-thujaplicin and other tropolones, and derivatives of thymoquinone have been reported to occur in the heartwood of this species (Zavarin et al. 1959, Pilo & Runeberg 1960). See also Calocedrus decurrens Florin.

Juniperus communis L.

Common Juniper

Juniper oil rubbed onto the skin produces a burning sensation with slight reddening, and even blistering if occluded (Nothnagel 1870). Externally, oil of juniper berry is skin irritant (Nadkarni 1976). Rothe et al. (1973) found juniper berry oil to be an occupational allergen to the skin and respiratory tract.

Williams Lord (1933) described oil of cadeberry, a combination of green Barbados tar (obtained from seepage from coral) and oil of juniper berry. He noted that it was almost entirely non-irritant to the skin, but that one occasionally saw infants who seemed to be definitely sensitive to it.

β-Thujaplicin, the contact allergenic properties of which were investigated by Ito (1964), has been detected in trace amounts in the heartwood of this species (Zavarin et al. 1959). See also Calocedrus decurrens Florin.

Juniperus lucayana Britton

West Indies Cedar

Hartwell et al. (1953) and Fitzgerald et al. (1957) reported the presence of podophyllotoxin in this species. (See Podophyllum peltatum L., fam. Podophyllaceae).

Juniperus macropoda Boiss.

Juniper

This species can have irritant properties (Behl et al. 1966). When smoked, this juniper has strongly hallucinogenic properties (Siegel 1976).

Juniperus mexicana Schiede

Texas Cedar

Wood cutters in Texas, where the pollen is a common cause of pollinosis (Wodehouse 1971), have developed dermatitis from J. mexicana. The aromatic oil of the tree, or lichens on the bark have been suggested as the causative agents (Morton 1977a).

The fragrance raw material cedarwood oil Texas is derived from J. mexicana by steam distillation of the wood. No irritant, sensitising, nor phototoxic effects could be demonstrated with the oil in a variety of test procedures (Opdyke 1976, p. 711). Sax (1975) reported that the oil possesses slight activity as a local irritant or allergen.

Juniperus oxycedrus L.

Prickly Juniper

Irritant and probably allergic dermatitis can result from application of oil of cade derived from the wood of this tree by destructive distillation (White 1887, Gougerot & Blamoutier 1922a, Nelson 1932, Williams Lord 1933, Grolnick 1938a, Greenberg & Lester 1954). Acneiform eruptions can also result from the use of oil of cade (White 1887).

Juniperus phoenicia L.

Phoenician Juniper

Carvacrol and β-thujaplicin have been reported from the heartwood of this species (Runeberg 1960b). Positive patch test reactions to these compounds have been observed (see Calocedrus decurrens Florin).

Juniperus procera Hochst.

African Juniper

The wood can cause dermatitis, conjunctivitis, and rhinitis in wood-workers (Piorkowski 1944, Watt & Breyer-Brandwijk 1962).

Juniperus sabina L.

[syn. Juniperus lusitanica Mill.]

Savin

Piffard (1881) recorded that "the twigs cause inflammation of the skin". Harrison (1906) included savin in a list of drugs, applied externally or taken internally, which may cause dermatitis.

According to Stuart (1979), savin has a long history as a stimulant veterinary drug in Europe, and was applied to the wounds and ulcers of animals. As a human medicine it is now only used externally, if at all (because of its toxicity), as a stimulant dressing for blisters, wounds, and ulcers, and to remove warts.

Savin oil, obtained by steam distillation of the plant material, is a violent irritant both internally and externally (Todd 1967). If applied to the skin, it can produce erythema and blistering (Fasal 1926).

The species and also J. sabina var. tamariscifolia yield podophyllotoxin (Hartwell et al. 1953, Fitzgerald et al. 1957), the irritant properties of which are well known (see Podophyllum peltatum L., fam. Podophyllaceae).

Juniperus scopulorum Sargent

Podophyllotoxin has been reported from this species (Hartwell et al. 1953, Fitzgerald et al. 1957). See also Podophyllum peltatum L., fam. Podophyllaceae.

Juniperus silicicola Bailey

[syn. Sabina silicicola Small]

Hartwell et al. (1952) reported the isolation of silicicolin, a lignan, from the heartwood of this species. This was subsequently shown to be desoxypodophyllotoxin (Hartwell & Schrecker 1954). See also Podophyllum peltatum L., fam. Podophyllaceae.

Juniperus thurifera L.

Juniperus utahensis Lemmon

Utah Juniper

Carvacrol and β-thujaplicin have been reported from both of these species (Runeberg 1960c, 1960d). Positive patch test reactions to these compounds have been observed (see Calocedrus decurrens Florin).

Juniperus virginiana L.

Red Cedar, Pencil Cedar

Incense cedar and Virginian pencil cedar (probably Juniperus virginiana L.) are both officially recognised causes of dermatitis in the German pencil industry (Koelsch 1931).

The leaves were used in an ointment for their irritant and rubefacient properties (White 1887).

The fragrance raw material known as cedarwood oil Virginia, red cedarwood oil, or oil cedar is obtained from this species by steam distillation of the sawdust. The principal constituents are cedrene, thujopsene, and cedrol. The oil was found to be moderately irritating to rabbit skin when applied under occlusion for 24 hours. On mouse skin, and at a dilution of 8% in petrolatum on human skin in a 48 hour closed patch test, the oil was non-irritant. No sensitising nor phototoxic effects could be demonstrated (Opdyke 1974, p. 845). However, the use of toilet preparations containing cedarwood oil followed by exposure to sunlight is sometimes a cause of dermatitis (Bray 1937, Greenbaum 1934). Pigmentation may follow the topical application of cedarwood oil (del Vivo 1930, Sandler 1939).

Podophyllotoxin has been reported to occur in this species (Hartwell et al. 1953, Fitzgerald et al. 1957). See also Podophyllum peltatum L., fam. Podophyllaceae.

Papuacedrus torricellensis Li

[syn. Libocedrus torricellensis Schlechter]

β-Thujaplicin, the contact allergenic properties of which have been investigated by Ito (1964), has been reported to occur in the heartwood of this species. See also Calocedrus decurrens Florin.

Platycladus orientalis Franco

[syn. Thuja orientalis L.]

Oriental Arbor-Vitae

The leaves and branches of this species and of Thuja occidentalis L. can produce dermatitis in gardeners (Genner & Bonnevie 1938, Schwartz et al. 1957). Contact dermatitis from the leaf of Thuja orientalis was reported by Zubiri & Obras-Loscertales (1970).

Sequoia sempervirens (D.Don) Endl.

[syn. Taxodium sempervirens D.Don]

California Redwood, Coast Redwood, Sequoia, Küstenmammutbaum

Oliver (1902) described coryzal symptoms in men sawing and chipping sequoia wood. They complained of running at the nose, sneezing, coughing, laboured breathing, oppression at the pit of the stomach and smarting in the eyes and were noted to have tachycardia. The symptoms were worst on the first exposure and lasted about 24 hours but tolerance later developed except in asthma subjects. Cabinet-makers developed dermatitis when working with the wood (MacPherson 1925). Bleumink & Nater (1974b) found no positive patch test reactions to an ethanolic extract of the wood in 20 patients allergic to woods.

Cohen et al. (1967) described a case of pneumonitis (sequoiosis) with circulating antibodies to redwood sawdust (or possibly to an associated fungus) in a sawmill worker. Morgan and Seaton (1975) also referred to this condition.

Tetraclinis articulata Masters

[syns Thuya articulata Vahl, Callitris articulata Murb., Callitris quadrivalis Vent.]

Arar Tree

In NW Moroccan traditional medicine, the leaves of this plant mixed with henna leaves (Lawsonia inermis L., fam. Lythraceae) are powdered and kneaded with water to make a hair tonic for external application (Merzouki et al. 2000).

The heartwood of this species is known to contain several dermatologically active compounds including thymoquinone, carvacrol, and β- and γ-thujaplicins (Erdtman & Rennerfelt 1949, Chow & Erdtman 1962). Calnan (1972) and Woods & Calnan (1976) were probably referring to this species and to this earlier literature when they asserted that Callitris articulata Vahl [sic] contains thymoquinone. See also Calocedrus decurrens Florin, Thuja plicata Donn ex D.Don.

Thuja L.

Five species are to be found in China, Japan, and North America.

An irritant and possibly a sensitiser is present in Thuja leaves (Sachs 1926, McCord 1962, Schwartz et al. 1957).

Thuja douglasii Nutt.

This species can excite irritation of the skin by contact (Maiden 1909b).

Thuja occidentalis L.

Arbor Vitae, False White Cedar, Yellow Cedar

The name white cedar is applied to this species and to Chamaecyparis thyoides Britton and Calocedrus decurrens Florin.

The plant, or a decoction of it irritates and inflames the skin like Juniperus sabina L. (Cantani 1876). Felter & Lloyd (1898), citing Howe (1880; Eclectic Medical Journal, p. 331) record that "A tincture of fresh leaves of thuja will, locally applied, according to my experience, remove warts from the face and hands, condylomata about the nates, but will not destroy swiftly growing venereal warts. It will deaden fungous granulations, and utterly destroy them in some instances. But the best action of the drug is in overcoming the growing and spreading progress of epithelioma. I have seen it repress and overcome fungoid and ulcerous epitheliomata in an astonishingly happy manner." Citing Howe further, they record that "Thuja comes highly recommended as a dressing for sloughing wounds, ulcers, bedsores, senile and other forms of gangrene, serving a useful purpose in overcoming the horrible stench arising therefrom. It may likewise be used in carcinomatous ulcerations. Some even claim that it has power to check the latter disorder, but in all probability, this is claiming too much for the drug. It is frequently valuable to restrain hemorrhages occasioned by malignant growths." References in the more recent literature to the use of preparations of Thuya occidentalis for the removal of warts and fungoid growths (for example: Wren 1975) evidently relate to Howe's observations.

The tree can produce dermatitis in gardeners (Genner & Bonnevie 1938, Schwartz et al. 1957). Several men working with white cedar developed dermatitis of the hands; another man had pharyngitis and bronchitis, but no dermatitis (Sachs 1926).

The fragrance raw material cedar leaf oil or oil thuja (also known as oil of arbor-vitae or oil of white cedar) is derived from this species by steam distillation of the fresh branch ends and leaves. The oil was found to be moderately irritating to rabbit skin when applied under occlusion for 24 hours. A 4% dilution in petrolatum was not irritant to human skin in a 48 hour closed patch test. No sensitising properties could be demonstrated in 25 human volunteers; no phototoxic effects have been reported (Opdyke 1974, p. 843).

Thuja plicata Donn ex D.Don

[syn. Thuja gigantea Nutt.]

Western Red Cedar, Giant Arbor-Vitae, Giant Cedar

Bleumink et al. (1973b) investigated a woodworker with acute dermatitis of the face, hands, and arms. He reacted to patch tests with western red cedar and to aqueous and ethanolic extracts prepared from it. Several other woods were also tested but gave negative results. Positive reactions to γ-thujaplicin (which is 5-isopropyltropolone), β-thujaplicinol (which is 7-hydroxy-4-isopropyltropolone), thymoquinone, and to methyl-p-benzoquinone, but not to β-thujaplicin (all 1% in ethanol) were also observed. Thymoquinone was noted to be both an irritant and a potent elicitor of allergic contact dermatitis. Seventy six cases of dermatitis from the sawdust were reported by Ishizaki et al. (1973). Conjunctivitis, urticaria, rhinitis, and asthma were also observed.

A patient who exhibited positive patch tests reactions to extracts of both western red cedar and incense cedar (Calocedrus decurrens Florin) was reported by Calnan (1972). A joiner who had dermatitis showed positive patch test reactions to Thuja plicata and oak (Quercus L., fam. Fagaceae), negative to some other woods (Woods & Calnan 1976).

"Cedar poisoning", a form of allergic contact dermatitis sometimes presented by forest workers, results from exposure to lichens and liverworts which grow on the trees (Tan & Mitchell 1968, Mitchell et al. 1972a). An ethyl acetate extract but not a diethyl ether extract of wood from a tree identified only as "western cedar" and "red cedar" growing in the forests of Oregon, USA, but probably this species, exhibited a high degree of sensitisation in guinea pigs (Suskind 1967).

The wood dust can produce allergic respiratory symptoms in wood-workers (Chan-Yeung 1982, Brooks et al. 1981, Mue et al. 1975, Mitchell & Chan-Yeung 1974, Chan-Yeung et al. 1973, Pickering et al. 1972, Mitchell 1970, Gandevia & Milne 1970, Gandevia 1970, Milne & Gandevia 1969, Doig 1949). The responsible agent is plicatic acid. Asthma has also been reported in persons working with urea formaldehyde / western red cedar particle board (Cockcroft et al. 1982).

The main symptoms in 1320 persons with reactions to western red cedar, and the rate of occurrence were (Yasue 1973): asthma 3.6%; nasal inflammation 5.6%; urticaria 3.1%; skin infection 3.0%; conjunctivitis 5.1%.

A number of persons living in houses built of western red cedar after the 1923 Tokyo earthquake developed "beisugi asthma" (Hausen 1970).

Thuja standishii Carrière

[syn. Thuja japonica Maxim.]

Japanese Arbor-Vitae, Standish Arbor-Vitae

The wood can cause dermatitis and respiratory symptoms in wood-workers (Ito 1963, Komatsu 1964, Yasue 1973). The contact sensitiser is β-thujaplicin (Ito 1964).

Thujopsis dolabrata Siebold & Zucc. var. hondai Makino

Hiba Arbor-Vitae

The fragrance raw material hibawood oil is obtained from the sawdust and trunk wood shavings of this tree by steam distillation. It was found to be moderately irritating to rabbit skin when applied under occlusion for 24 hours. At a dilution of 12% in petrolatum, it was non-irritant to human skin in a 48 hour closed patch test. No sensitising nor phototoxic properties could be detected (Opdyke 1979, p. 817).

DERMATOLOGY

Contact dermatitis from timbers is usually attributable to contamination of the skin during machining. Handling of solid wood rarely induces dermatitis, but Calocedrus (and also Dalbergia L.f., fam. Leguminosae) used for pencils, etc. may do so (Calnan 1972).

Thymoquinone is very irritant in high concentration, and may be so at 1%; a concentration of 0.1% is recommended for patch testing (Calnan 1972, Hausen 1981). Bleumink & Nater (1974b) observed a positive patch test reaction to thymoquinone (0.1%).

β-Thujaplicin, which is also known as hinokitiol, is used in Japan in hair tonics for its bactericidal properties. A male aged 60 years, who had dermatitis of the face, scalp, and hands associated with the use of such a lotion showed positive patch test reactions to β-thujaplicin (0.1% in ethanol) as well as to pyridoxine-3,4-dioctanoate (0.001% in ethanol), pyridoxine hydrochloride (1% in petrolatum), and 10% aqueous propylene glycol (Fujita & Aoki 1983).

Primin was found not to be an elicitor in cases of tropolone (γ-thujaplicin and β-thujaplicinol) and thymoquinone allergy (Bleumink et al. 1973b).

References

• Anderson AB, Scheffer TC, Duncan CG (1963) The chemistry of decay resistance and its decrease with heartwood aging in incense cedar (Libocedrus decurrens Torrey). Holzforschung 17(1): 1-5 [doi] [url]
• Aynehchi Y (1971) Desoxypodophyllotoxin, the cytotoxic principle of Callitris columellaris F. Muell. Journal of Pharmaceutical Sciences 60(1): 121-122 [doi] [url] [url-2] [pmid]
• Behl PN, Captain RM, Bedi BMS, Gupta S (1966) Skin-Irritant and Sensitizing Plants Found in India. New Delhi: PN Behl [WorldCat]
• Black JH (1929) Cedar hay fever. Journal of Allergy 1(1): 71-73 [doi] [url]
• Bleumink E, Nater JP (1974b) Allergic reactions to (tropical) woods. Contact Dermatitis Newsletter (15): 436-437 [url]
• Bleumink E, Mitchell JC, Nater JP (1973b) Allergic contact dermatitis from cedar wood (Thuja plicata). British Journal of Dermatology 88(5): 499-504 [doi] [url] [url-2] [pmid]
• Boas IH (1947) The Commercial Timbers of Australia. Their Properties and Uses. Melbourne: Government Printer, Commonwealth of Australia. Council for Scientific and Industrial Research.
• Bray GW (1937) Recent Advances in Allergy. Philadelphia: Blakiston.
• Brecknell DJ, Carman RM (1978) Callitrin, callitrisin, dihydrocallitrisin, columellarin and dihydrocolumellarin, new sesquiterpene lactones from the heartwood of Callitris columellaris. Tetrahedron Letters 19(1): 73-76 [doi] [url]
• Brecknell DJ, Carman RM (1979) Novel sesquiterpene lactones from Callitris columellaris heartwood. Australian Journal of Chemistry 32(11): 2455-2471 [doi] [url]
• Brooks SM, Edwards JJ, Apol A, Edwards FH (1981) An epidemiologic study of workers exposed to western red cedar and other wood dusts. Chest 80(1 Suppl): 30-32 [doi] [url] [url-2] [pmid]
• Calnan CD (1972) Dermatitis from cedar wood pencils. Transactions of the St John's Hospital Dermatological Society 58(1): 43-47 [doi] [url] [url-2] [pmid]
• Cantani (1876)
• Chan-Yeung M (1982) Immunologic and nonimmunologic mechanisms in asthma due to western red cedar (Thuja plicata). Journal of Allergy and Clinical Immunology 70(1): 32-37 [doi] [url] [url-2] [pmid]
• Chan-Yeung M, Barton GM, MacLean L, Grzybowski S (1973) Occupational asthma and rhinitis due to western red cedar (Thuja plicata). American Review of Respiratory Diseases 108(5): 1094-1102 [doi] [url] [url-2] [pmid]
• Chow Y-L, Erdtman H (1962) The chemistry of the natural order Cupressales. 42. Heartwood constituents of Tetraclinis articulata (Vahl) Masters. Acta Chemica Scandinavica 16(6): 1291-1295 [doi] [url] [url-2]
• Cleland JB (1925) Plants, including fungi, poisonous or otherwise injurious to man in Australia. Medical Journal of Australia ii(15): 443-451 [doi] [doi-2] [url] [url-2]
• Cockcroft DW, Hoeppner VH, Dolovich J (1982) Occupational asthma caused by cedar urea formaldehyde particle board. Chest 82(1): 49-53 [doi] [url] [url-2] [pmid]
• Cohen HI, Merigan TC, Kosek JC, Eldridge F (1967) Sequoiosis. A granulomatous pneumonitis associated with redwood sawdust inhalation. American Journal of Medicine 43(5): 785-794 [doi] [url] [url-2] [pmid]
• del Vivo G (1930) A proposito dell'azione di alcuni olii essenziali sulla pigmentazione. [On the action of some essential oils on pigmentation]. Giornale Italiano di Dermatologia e Sifilologia 71(2): 467-480
• Doig AT (1949) Other lung diseases due to dust. Postgraduate Medical Journal 25(290): 639-649 [doi] [url] [url-2] [pmid]
• Enzell C (1960) The chemistry of the natural order Cupressales. XXIV. Heartwood constituents of Chamaecyparis thyoides (L) Britt. Acta Chemica Scandinavica 14(1): 81-85 [doi] [url] [url-2]
• Enzell C, Erdtman H (1957) The chemistry of the natural order Cupressales. XIX. The occurrence of manool in Cupressus sempervirens L. Acta Chemica Scandinavica 11(5): 902-903 [doi] [url] [url-2]
• Erdtman H, Rennerfelt E (1949) Fungicidal properties of some constituents of the heartwood of Tetraclinis articulata (Vahl) Masters. Acta Chemica Scandinavica 3(7): 906-911 [doi] [url] [url-2]
• Fasal H (1926) Alkohole, Äther, ätherische Öle, Essenzen. In: Oppenheim M, Rille JH, Ullmann K (Eds) Die Schädigungen der Haut durch Beruf und gewerbliche Arbeit, Vol. 2, pp. 194-199. Leipzig: Leopold Voss
• Felter HW, Lloyd JU (1898) King's American Dispensatory, 18th edn; 3rd revn, I & II. Cincinnati: Ohio Valley [WorldCat] [url]
• Fitzgerald DB, Hartwell JL, Leiter J (1957) Distribution of tumor-damaging lignans among conifers. Journal of the National Cancer Institute 18(1): 83-99 [doi] [url] [pmid]
• Fujita M, Aoki T (1983) Allergic contact dermatitis to pyridoxine ester and hinokitiol. Contact Dermatitis 9(1): 61-65 [doi] [url] [url-2] [pmid]
• Gandevia B (1970) Ventilatory capacity during exposure to western red cedar. Archives of Environmental Health 20(1): 59-63 [doi] [url] [pmid]
• Gandevia B, Milne J (1970) Occupational asthma and rhinitis due to western red cedar (Thuja plicata) with special reference to bronchial reactivity. British Journal of Industrial Medicine 27(3): 235-244 [doi] [doi-2] [url] [url-2] [pmid]
• Genner V, Bonnevie P (1938) Eczematous eruptions produced by leaves of trees and bushes. Archives of Dermatology and Syphilology 37(4): 583-589 [doi] [url]
• Gougerot, Blamoutier (1922a) Intolérance anaphylactique aux applications médicamenteuses externes. Choc hémoclasique par application d'huile de cade; désensibilisation par voie externe en dermatologie. [Anaphylactic intolerance to external drug applications. Hemoclastic shock by application of cade oil; external desensitization in dermatology]. Bulletins et Mémoires de la Société Médicale des Hôpitaux de Paris 46: 733-739 [url] [url-2]
• Greenbaum SS (1934) Cutaneous photo-pigmentation and cosmetics. With special reference to berlock dermatitis. Pennsylvania Medical Journal 38(1): 28-31 [url]
• Greenberg LA, Lester D (1954) Handbook of Cosmetic Materials. Their properties, uses, and toxic and dermatologic actions. With a bibliography of over 2,500 titles. New York: Interscience Publishers [doi] [WorldCat] [url] [url-2]
• Grolnick M (1938) Dermatitis due to hemorrhoidal ointment containing krameria and oil of cade. Journal of the American Medical Association 110(13): 951-952 [doi] [url]
• Harrison AJ (1906) Dermatitis from without and dermatitis from within. Bristol Medico-Chirurgical Journal 24(94): 325-343 [url] [url-2] [pmid]
• Hartwell JL, Johnson JM, Fitzgerald DB, Belkin M (1952) Silicicolin, a new compound isolated from Juniperus silicicola. Journal of the American Chemical Society 74(17): 4470 [doi] [url] [url-2]
• Hartwell JL, Johnson JM, Fitzgerald DB, Belkin M (1953) Podophyllotoxin from Juniperus species; savinin. Journal of the American Chemical Society 75(1): 235-236 [doi] [url] [url-2]
• Hartwell JL, Schrecker AW (1954) Relationship of anthricin, hernandion, and cicutin to desoxypodophyllotoxin. Journal of the American Chemical Society 76(15): 4034-4035 [doi] [url] [url-2]
• Hausen BM (1970) Untersuchungen über Gesundheitsschädigende Hölzer [Studies on Harmful Woods]. Doctoral Dissertation. Universität Hamburg, Germany [url] [url-2]
• Hausen BM (1981a) Woods Injurious to Human Health. A manual. Berlin: Walter de Gruyter [WorldCat]
• Hindson C, Lawlor F, Downey A (1982) Cross sensitivity between zinc oxide plaster and Cupressus Leylandii shrubs. Contact Dermatitis 8(5): 335 [doi] [url] [url-2] [pmid]
• Hjorth N (1968) Personal communication to Mitchell JC. In: Mitchell J, Rook A (1979). Vancouver: Greengrass, p. 243 [WorldCat]
• Ishizaki T, Shida T, Miyamoto T, Matsumara Y, Mizuno K (1973) Occupational asthma from western red cedar dust (Thuja plicata) in furniture factory workers. Journal of Occupational Medicine 15(7): 580-585 [url] [pmid]
• Ito K (1963) Allergic disorders of upper respiratory tract by sawdust of Thuja standishii Carr. Rodo Kagaku (Journal of Sci. Labour, Tokyo) 39: 27, 80, 501, & 568
• Ito K (1964) An antigenic substance, beta-thujaplicin in the steam-distillate of the sawdust of Thuja standishii Carr. Medical Journal of Shinshu University 9(3-4): 165-170
• Koelsch F (1931) Die Begutachtung der gewerblichen Dermatosen im Sinne der Verordnung vom 11 Februar 1929. Zentralblatt für Haut- und Geschlechtskrankheiten 37(1/2): 1-17
• Komatsu F (1964) Respiratory allergy in woodworkers. Excerpta Medica Int. Congr. Ser. 62: 1748
• Kupchan SM, Hemingway RJ, Hemingway JC (1967) Tumor inhibitors XIX. Desoxypodophyllotoxin, the cytotoxic principle of Libocedrus decurrens. Journal of Pharmaceutical Sciences 56(3): 408-409 [doi] [url] [url-2]
• Lewith R (1929) Pallissanderholzdermatitis. Zentralblatt für Haut- und Geschlechtskrankheiten 30(1/2): 8
• MacPherson J (1925) Dermatitis caused by Queensland maple. Medical Journal of Australia ii(18): 542
• Maiden JH (1909b) On some plants which cause inflammation or irritation of the skin. Part II. Agricultural Gazette of New South Wales 20(12): 1073-1082 [url] [url-2]
• Maiden JH (1921a) Plants which produce inflammation or irritation of the skin. Agricultural Gazette of New South Wales 32(3): 206 [url] [url-2]
• Masumura M (1955) ちゃぼひば若葉成分に関する研究(第4報). ヒノキ酸および d-セサミン [Constituents of young leaves of chyabohiba. IV. Hinokinic acid and d-sesamin]. Nippon Kagaku Zasshi – Journal of the Chemical Society of Japan, Pure Chemistry Section 76(11): 1318-1322 [doi] [url] [url-2]
• Mathias CGT, Maibach HI, Mitchell JC (1979) Plant dermatitis — patch test results (1975—78). Note on Juniperus extract. Contact Dermatitis 5(5): 336 [doi] [url] [url-2] [pmid]
• McCord CP (1962) The occupational toxicity of cultivated flowers. Industrial Medicine and Surgery 31(8): 365-368
• Merzouki A, Ed-derfoufi F, Molero Mesa J (2000) Contribution to the knowledge of Rifian traditional medicine. II: Folk medicine in Ksar Lakbir district (NW Morocco). Fitoterapia 71(3): 278-307 [doi] [url] [pmid]
• Milne J, Gandevia B (1969) Occupational asthma and rhinitis due to western (Canadian) red cedar (Thuja plicata). Medical Journal of Australia ii(15): 741-744 [pmid]
• Mitchell C (1970) Occupational asthma due to Western or Canadian red cedar (Thuja plicata). Medical Journal of Australia ii(5): 233-235 [pmid]
• Mitchell JC, Chan-Yeung M (1974) Contact allergy from Frullania and respiratory allergy from Thuja. Canadian Medical Association Journal 110(6): 653-654 [url] [url-2] [pmid]
• Mitchell JC, Dupuis G, Geissman TA (1972a) Allergic contact dermatitis from sesquiterpenoids of plants. Additional allergenic sesquiterpene lactones and immunological specificity of Compositae, liverworts and lichens. British Journal of Dermatology 87(3): 235-240 [doi] [url] [url-2] [pmid]
• Morgan. W.K.C. and Seaton, A. (1975) Occupational Lung Diseases. Philadelphia, Saunders.
• Morton (1977a)
• Mue S, Ise T, Ono Y, Akasaka K (1975) A study of western red cedar-induced asthma. Annals of Allergy 34(5): 296-304 [pmid]
• Nadkarni AK (1976) Dr. K. M. Nadkarni's Indian Materia Medica. With ayurvedic, unani-tibbi, siddha, allopathic, homeopathic, naturopathic & home remedies, appendices & indexes, Revised enlarged and reprinted 3rd edn, Vols 1 & 2. Bombay: Popular Prakashan [WorldCat] [url] [url-2]
• Nelson T (1932) Contact dermatitis to oil of cade. Journal of Allergy 3(3): 319 [doi] [url]
• Nothnagel H (1870) Handbuch der Arzneimittellehre. [Handbook of Pharmacology]. Berlin: August Hirschwald [WorldCat] [url] [url-2]
• Oleffe J, Dedeken H, Sporcq J, Hublet P (1974) Dermatoses professionnelles provoquées par les bois tropicaux en Belgique. [Occupational skin diseases due to tropical woods in Belgium]. Archives Belges de Dermatologie 30(2): 75-82 [pmid]
• Oleffe JA, Sporcq J, Hublet P (1975a) Epidemiological study of the wood industry in Belgium. Contact Dermatitis 1(5): 315-316 [doi] [url] [url-2] [pmid]
• Oleffe JA, Dedeken H, Sporcq J (1975b) Occupational dermatitis from alerce (Fitzroya Cupressoides). Contact Dermatitis 1(5): 319 [doi] [url] [url-2] [pmid]
• Oleffe JA, Dedeken H, Sporcq J, Hublet P (1975c) Allergie cutanée professionnelle à l'alerce (Fitzroya cupressoides). [Occupational skin allergy to alerce (Fitzroya cupressoides)]. Berufsdermatosen 23(6): 196-201 [pmid]
• Oliver T (Ed.) (1902) Dangerous Trades. The Historical, Social, and Legal Aspects of Industrial Occupations as Affecting Health, by a Number of Experts. London: J. Murray
• Opdyke DLJ (1974) Fragrance raw materials monographs. Cedar leaf oil. Food and Cosmetics Toxicology 12(Suppl): 843-844 [doi] [url]
• Opdyke DLJ (1974) Fragrance raw materials monographs. Cedarwood oil Virginia. Food and Cosmetics Toxicology 12(Suppl): 845-846 [doi] [url]
• Opdyke DLJ (1976) Fragrance raw materials monographs. Cedarwood oil Texas. Food and Cosmetics Toxicology 14(Suppl): 711-712 [doi] [url]
• Opdyke DLJ (1978) Fragrance raw materials monographs. Cypress oil. Food and Cosmetics Toxicology 16(Suppl 1): 699 [doi] [url]
• Opdyke DLJ (1979) Fragrance raw materials monographs. Hibawood oil. Food and Cosmetics Toxicology 17(Suppl): 817 [doi] [url]
• Orsler RJ (1973) Personal communication to JC Mitchell from the Forest Products Research Laboratory, Princes Risborough, England. In: Mitchell J, Rook A (1979). Botanical Dermatology. Plants and plant products injurious to the skin. Vancouver: Greengrass, pp. 242, 243 [WorldCat] [url]
• Pickering CAC, Batten JC, Pepys J (1972) Asthma due to inhaled wood dusts — Western red cedar and iroko. Clinical Allergy 2(3): 213-218 [doi] [url] [url-2] [pmid]
• Piffard HG (1881) A Treatise on the Materia Medica and Therapeutics of the Skin. New York: William Wood & Company [WorldCat] [url] [url-2]
• Pilo C, Runeberg J (1960) The chemistry of the natural order Cupressales. XXV. Heartwood constituents of Juniperus chinensis L. Acta Chemica Scandinavica 14(2): 353-358 [doi] [url] [url-2]
• Piorkowski FO (1944) Woodworker's dermatitis in East Africa. East African Medical Journal 21(2): 60-64
• Prosser White R (1934) The Dermatergoses or Occupational Affections of the Skin, 4th edn. London: HK Lewis [doi] [WorldCat] [url] [url-2]
• Ramazzini B (1713) De Morbis Artificum Diatriba. The Latin text of 1713, revised, with translation and notes by Wilmer Cave Wright in 1940 (History of Medicine Series. No. 7). Chicago: University of Chicago Press
• Rasch (1923/4) Cypresdermatitis. Verhandlung der Deutschen Dermatologischen Gesellschaft 42. Cited by Touton (1932)
• Rothe A, Heine A, Rebohle E (1973) Wacholderbeeröl als Berufsallergen für Haut und Atemtrakt. [Oil from juniper berries as an occupational allergen for the skin and respiratory tract]. Berufsdermatosen 21(1): 11-16 [pmid]
• Runeberg J (1960) The chemistry of the natural order Cupressales. XXIX. Heartwood constituents of Juniperus thurifera L. Acta Chemica Scandinavica 14(9): 1985-1990 [doi] [url] [url-2]
• Runeberg J (1960) The chemistry of the natural order Cupressales. XXVII. Heartwood constituents of Juniperus utahensis Lemm. Acta Chemica Scandinavica 14(4): 797-804 [doi] [url] [url-2]
• Runeberg J (1960) The chemistry of the natural order Cupressales. XXX. Heartwood constituents of Juniperus cedrus L. Acta Chemica Scandinavica 14(9): 1991-1994 [doi] [url] [url-2]
• Runeberg J (1960) The chemistry of the natural order Cupressales. XXXI. Heartwood constituents of Juniperus phoenicea L. Acta Chemica Scandinavica 14(9): 1995-1998 [doi] [url] [url-2]
• Sachs O (1926) Beitrag zur Frage der Ueberempfindlichkeit der Haut. Wiener Medizinische Wochenschrift 76(31): 933-934
• Sandler IL (1939) Photosensitizing agents. A brief review of the literature. Journal of the American Medical Association 112(23): 2411-2413 [doi] [url]
• Sargent CS (1896) The Sylva of North America. Vol. 10. Boston: Houghton Mifflin. Cited by Woods & Calnan (1976)
• Sax NI (1975) Dangerous Properties of Industrial Materials. 4th edn. New York: Reinhold Book Corp. Cited by Opdyke (1976, p. 711)
• Schonwald P (1929) In Discussion of Black (1929)
• Schwartz L, Tulipan L, Birmingham DJ (1957) Irritant plants and woods. In: Occupational Diseases of the Skin. 3rd edn, pp. 636-672. London: Henry Kimpton [doi] [WorldCat] [url] [url-2]
• Siegel RK (1976) Herbal intoxication. Psychoactive effects from herbal cigarettes, tea, and capsules. JAMA 236(5): 473-476 [doi] [url] [pmid]
• Stier RFE (1929) In Discussion of Black (1929)
• Stuart M (1979) Reference section. In: Stuart M (Ed.) The Encyclopedia of Herbs and Herbalism, pp. 141-283. London: Orbis Publishing [WorldCat] [url]
• Suskind RR (1967) Dermatitis in the forest product industries. Archives of Environmental Health 15(3): 322-326 [doi] [url] [pmid]
• Tan KS, Mitchell JC (1968) Patch and photopatch tests in contact dermatitis and photodermatitis: a preliminary report of investigation of 150 patients, with special reference to "cedar-poisoning". Canadian Medical Association Journal 98(5): 252-255 [url] [url-2] [pmid]
• Todd RG (Ed.) (1967) Martindale. The Extra Pharmacopoeia. 25th edn. London: Pharmaceutical Press [WorldCat]
• Touton K (1932) Hauterkrankungen durch phanerogamische Pflanzen und ihre Produkte (Toxicodermia et Allergodermia phytogenes) [Skin Diseases Caused by Phanerogamic Plants and their Products (Toxicodermia et Allergodermia phytogenes)]. In: Jadassohn J (Ed.) Handbuch der Haut- und Geschlechtskrankheiten. Band IV, Teil I. Angeborene Anomalien. Lichtdermatosen. Pflanzengifte. Thermische Schädigungen. Einfluss Innerer Störungen auf die Haut [Handbook of Skin and Venereal Diseases. Volume IV, Part I. Congenital abnormalities. Photodermatoses. Plant toxins. Thermal injuries. Influence of internal disorders on the skin], pp. 487-697. Berlin: Julius Springer [doi] [WorldCat] [url] [url-2]
• Watt JM, Breyer-Brandwijk MG (1962) The Medicinal and Poisonous Plants of Southern and Eastern Africa. Being an account of their medicinal and other uses, chemical composition, pharmacological effects and toxicology in man and animal, 2nd edn. Edinburgh: E & S Livingstone [doi] [WorldCat] [url] [url-2]
• White JC (1887) Dermatitis Venenata: an account of the action of external irritants upon the skin. Boston: Cupples and Hurd [doi] [WorldCat] [url] [url-2]
• Williams Lord L (1933) Oil of cadeberry. A little known drug that is valuable in certain dermatoses. Archives of Dermatology and Syphilology 28(1): 29-31 [doi] [url]
• Wodehouse RP (1971) Hayfever Plants. Their appearance, distribution, time of flowering, and their role in hayfever, 2nd revised edn. New York, NY: Hafner Publishing Company [WorldCat]
• Woods B, Calnan CD (1976) Toxic woods. British Journal of Dermatology 95(Suppl 13): 1-97 [doi] [url] [url-2] [pmid]
• Wren RC (1975) Potter's New Cyclopaedia of Botanical Drugs and Preparations. (Re-edited and enlarged by Wren RW). Bradford, Devon: Health Science Press [WorldCat] [doi] [url] [url-2]
• Yasue Y (1973) [Asthma due to western red cedar]. 木材工業 ~ Mokuzai Kōgyō ~ Wood Industry 28: 192-195 [url]
• Zavarin E, Smith LV, Bicho JG (1967) Tropolones of Cupressaceae—III. Phytochemistry 6(10): 1387-1394 [doi] [url]
• Zavarin E, Anderson AB (1955) Extractive components from incense-cedar heartwood (Libocedrus decurrens Torrey). I. Occurrence of carvacrol, hydrothymoquinone, and thymoquinone. Journal of Organic Chemistry 20(1): 82-88 [doi] [url] [url-2]
• Zavarin E, Anderson AB (1955) Extrahierbare Bestandteile des Kernholzes der Kalifornischen Flußzeder (incense-cedar, Libocedrus decurrens Torrey) IV. Vorkommen und Chromatographie von Thujaplicinen. [Extractable components of the heartwood of the California river cedar (incense cedar, Libocedrus decurrens Torrey) IV. Occurrence and chromatography of thujaplicins]. Chemische Berichte 89(2): 545-549 [doi] [url] [url-2]
• Zavarin E, Anderson AB (1956) Paper chromatography of the tropolones of Cupressaceae. Journal of Organic Chemistry 21(3): 332-335 [doi] [url] [url-2]
• Zavarin E, Smith RM, Anderson AB (1959) Paper chromatography of the tropolones of Cupressaceae II. Journal of Organic Chemistry 24(9): 1318-1321 [doi] [url] [url-2]
• Zubiri A, de las Obras-Loscertales JM (1970) Caso curioso de dermitis por contacto. [A peculiar case of contact dermatitis]. Actas Dermo-Sifiliográficas 61(9-10): 277-280

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