Wormwood is used to stimulate appetite or bile secretion. Only aqueous solutions or thujone-free extracts should be used; thujone is extremely toxic.
[LFDPKM ] Letter Key
Latin Name
Artemisia absinthium L.
Family
Compositae/Asteraceae
Description
- Wormwood, a gray shrub, has chrysanthemum-like leaves. The leaves and stems are covered with fine silky hairs. Native to the drier areas of Europe and Asia, wormwood was the main ingredient in the liqueur absinthe.
Part Used
Leaf, flowering tops
Known Active Constituents
- Artemesia absinthium contains sesquiterpene lactones, especially the guaianolides absinthin (0.2% to 0.28%). The essential oil contains mainly terpenes, including
-thujone, 
-thujone, trans-sabinyl acetate, and cis-epoxyocimene, as well as other monoterpenes and sesquiterpenes. It also contains flavonoids, phenolic carboxylic acids and polyacetylenes (1).
Mechanism/Pharmacokinetics
- Thujone, the highly toxic component of wormwood, appears to be a
-aminobutyric acid A (GABA A) receptor chloride channel blocker (2). Alpha-thujone is 2.3 times more active than -thujone at binding mammalian liver and brain (2). Thujone acts as a central nervous system poison; in cats, the minimal convulsive dose is 0.03 to 0.04 mL of a 1:20 alcohol dilution of essential oil administered intravenously. In rats, 10 mg/kg daily oral administration produced convulsions by Day 38 in 5% of the rats. Oral LD50 of mixed - and -thujones was 192 mg/kg in rats, 230 mg/kg in mice, and 395 mg/kg in guinea pigs (3). - No data on pharmacokinetics in humans are available.
[Outline]
[AP ] Letter Key
Adverse Reactions
- Acute renal failure
- A 31-year-old man, who purchased and consumed 10 mL of essential oil of wormwood (apparently he thought it was absinthe), was hospitalized for disorientation and tonic-clonic seizures with decorticate posturing; rhabdomyolysis and acute renal failure were evident by Day 2 (4).
- Epileptiform seizures have previously been associated with thujone (5).
- The toxic effects of absinthe became known as "absinthism"; symptoms included seizures, gastrointestinal problems, hallucinations, other psychiatric manifestations and increased risk of suicide.
Pregnancy/Lactation
This herb should not be used during pregnancy or lactation.
[Outline]
Q: What is absinthe?
A:Artemisia absinthium was the primary flavoring ingredient of the liqueur absinthe, which also contained anise (Pimpinella anisum), fennel (Foeniculum vulgare), Roman wormwood (A. pontica), hyssop (Hyssopus officinalis), and lemon balm (Melissa officinalis). Especially popular in Parisian cafes (some of which were devoted to its consumption), absinthe was usually consumed ritualistically; cold water trickled over a sugar cube held by a slotted spoon caused its emerald-green color to change to an opalescent yellow. Absinthe was the drink of choice among many artists and writers, including Picasso, van Gogh, Gauguin, Toulouse-Lautrec, Rimbaud, and Oscar Wilde. It has been known, however, since 1708, that A. absinthium caused deleterious effects on the nervous system. Banned in the United States in 1912 and in France in 1922 (6), absinthe is now illegal in most countries (although it was never formally banned in Spain, Portugal, the Czech Republic, or the United Kingdom) (5). It is still sold today. Analysis of one brand, "Hill’s Absinth," made in the Czech Republic and exported to the United Kingdom, found no thujone in the preparation (7) (see next question).
Q: Is it possible to minimize the toxicity of wormwood preparations?
A: Dilute aqueous extracts of dried wormwood contain only trace amounts of the essential oil and, thus, negligible amounts of thujone. Alcohol tinctures or extracts may contain a significant amount. There are, however, extraction procedures for removing thujone from wormwood extracts using water and ethanol 30% (V/V) or supercritical carbon dioxide. The use of the essential oil, very high in thujone, has been banned in most countries.
Q: Is it possible to minimize the bitter taste of wormwood?
A: Unfortunately, the bitter principles are what are therapeutically active, and stimulation of gastrointestinal secretions may not occur if the herb is swallowed in capsules rather than tasted (in dogs, oral administration, but not gavage, stimulated secretions). Although sweetener may be added to tea, it does not really help. A strong distaste for wormwood often develops in patients after a few weeks. Not a bad thing, considering concerns about long-term toxicity.
Q: Is wormwood a good antihelminthic?
A: Wormwood has some activity against worms and is sometimes used as a treatment for threadworm, but it is not particularly impressive. Levant wormseed (Artemesia cina) is more effective and shows activity against both threadworms and roundworms (8).