Tuja

Thuja occidentalis is a coniferous tree in the cypress family, native to eastern Canada and much of the north-central and northeastern United States. The foliage forms flat sprays of scale-like leaves 3-5 millimetres long. The genus Thuja has five species, two native to North America and three to eastern Asia, and T. occidentalis is its type species.

Oils from the leaves, from twigs with leaves and from twigs without leaves of the cultivar 'Brabant' contained mainly α-thujone (61.0-64.4%), β-thujone (10.4-10.7%) and fenchone (7.7-8.0%). The cone oil of the same cultivar held α-thujone (42.1%), sabinene (11.2%) and β-thujone (10.2%). In the cultivar 'Smaragd', the oils from leaves and from twigs with leaves were mainly α-thujone (49.2-49.3%), beyerene (12.8-13.2%) and sabinene (8.9-9.3%). Over seventy compounds were identified in these oils. The yield and chemical composition of the oil depend on the variety and the plant organ.

Thujone is a ketone and a monoterpene that occurs predominantly in two diastereomeric forms, (-)-α-thujone and (+)-β-thujone. Because of the neurotoxic compound thujone, internal use of the plant can be harmful if used for prolonged periods or while pregnant. The oil contains alpha-thujone and (+)-isothujone, which are restricted components under IFRA because of neurotoxicity, with maximum levels found of 55% and 10%.

The essential oil within the plant has been used for cleansers, disinfectants, hair preparations, insecticides, liniment, room sprays, and soft soaps.

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Related: Alder · Alpha Humulene · Amaranth · Amberever · Amburana Bark · Antillone · Apple Tree