Thujone, a widely debated volatile compound: What do we know about it?

Abstract

Thujone is a volatile monoterpene ketone of plant origin which is produced by several plants that are frequently used for flavoring foods and beverages. The use of thujone and thujone-containing plant parts for human consumption is currently regulated by the European Parliament and Council and the European Medicines Agency. The best known neurotoxic effects are connected to the GABA-gated chloride channel, where a-thujone is a modulator roughly two to three times as potent as the b isomer. Based primarily on in vitro experiments, genotoxicity and carcinogenic properties of thujones have also been detected in parallel with antimutagenic and immune-modulatory effects. Some of the controversial effects seem to be strongly dose-dependent. Data on antidiabetic and antimicrobial activities of thujones may show new ways to use them. This review also describes the main steps of the biosynthetic route of thujones and their occurrence in the plant kingdom. The accumulation of these compounds seems to be more abundant in some plant families (e.g. Asteraceae or Cupressaceae) than in others. Four species (Artemisia absinthium, Salvia

Thuja occidentalis L. (Cupressaceae): Ethnobotany, Phytochemistry and Biological Activity

“…The decoct and the tea prepared from the inner bark of the unwoody twigs could relieve constipation and headache [65]. It has also been used for the treatment of polyps, birthmarks, and wounds and as a painkilling and anthelmintic remedy [66,67]. In traditional medicine, T. occidentalis has been used in the treatment of liver diseases, bullous bronchitis, psoriasis, enuresis, amenorrhea, cystitis, uterine carcinomas, diarrhea, and rheumatism [58,[60][61][62].…”

“…The decoct and the tea prepared from the inner bark of the unwoody twigs could relieve constipation and headache [65]. It has also been used for the treatment of polyps, birthmarks, and wounds and as a painkilling and anthelmintic remedy [66,67].…”

“…Thujone is the monoterpene found in the composition of many plants including Thuja occidentalis. However, the use of this compound is regulated by the European Parliament and Council and the European Medicines Agency [67]. The isomers α-thujone and β-thujone are monoterpene ketones, with the following IUPAC name: (1S,4R,5R)-4-methyl-1-(propane-2-yl) bicyclo (3.1.0) hexan-3-one [67].…”

“…There are some corresponding enzymes of this transformation which have not yet been clarified and also the formation of the two isomers of thujone (α and β). There are some species who get both isomers, while other plants accumulate just one of them [67].…”

Essential Oils and Their Main Chemical Components: The Past 20 Years of Preclinical Studies in Melanoma

“…Moreover, EOs from Chrysanthemum boreale Makino, showed different levels of their component contents and bioactivities among the harvesting stages [ 31 ], while phytoconstituents and bioactivities of EOs from Curcuma kwangsiensis , strictly depended on the natural habitat [ 37 ]. Another example is provided by chemotaxonomical analysis of Artemisia absinthium , Salvia officinalis, Tanacetum vulgare and Thuja occidentalis , the amount of thujones (α-thujone and β-thujone) present in the EOs of the four species being strictly related to the plant organ and to its developmental phase [ 105 ]. Moreover, exposure to ultraviolet (UV) light was reported to induce deterioration of EOs’ biochemical profiles [ 49 ] or activation of some EOs [ 34 ].…”