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Wormwood - Medicinal Uses, Interactions, Side Effects, Dosage

Wormwood

Wormwood is a common name for specific plants of the Artemisia genus, which includes over 350 species worldwide. Two species used commonly in herbal medicine include A. absinthium (common wormwood) and A. annua (Chinese wormwood, or "qing hao").

Uses and Benefits:

Preparations of wormwood have been used as medicine for thousands of years. Common wormwood (A. absinthium) has traditionally been employed to eliminate parasitic worms and as an aromatic "bitter" to promote intestinal secretory activity for treating anorexia, dyspepsia, and "biliary dyskinesia." Absinthe, an alcoholic beverage made from A. absinthium extract, was extremely popular in turn-of-the-century France. Its mild hallucinogenic properties led to the belief that it stimulated "creative" and intellectual powers. Numerous artists, including Van Gogh, celebrated these effects; however, its use was ultimately banned because of purported CNS toxicity.

Chinese wormwood (A. annua) has been used for thousands of years by Chinese practitioners for the treatment of fever and related conditions, including malaria. In the 1970s, Chinese researchers isolated an active constituent of the herb, artemisinin (qinghaosu), and found that it had parasiticidal activity against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Artemisinin and several semi-synthetic derivatives are now used in Southeast Asia and Africa, especially for severe P. falciparum and multi-resistant malaria.

Pharmacology:

Common wormwood contains a number of biochemical compounds that have physiological effects. Absinthin and artabsin are believed responsible for the bitter properties of herb. Several studies of bitter oral wormwood extracts have ,monstrated increased gastric and biliary secretion in both animls and humans. The essential oil contains the terpenoid thume, which in toxic doses can cause autonomic excitability and onvulsions. Thujone is believed to be the ingredient in absinthe at is responsible for CNS toxicity. The structure of thujone is releated to camphor and tetrahydrocannabinol, the active component marijuana, which may account for some of the hallucinatory effects attributed to its use. Santonin, a sesquiterpene lactone isoladted from A. absinthium, can paralyze helminthic worms, which then unable to maintain their position within the bowellumenJ Other constituents of wormwood, including flavonoids, phenolic compounds, and coumarins, have in vitro antimicrobial, anti-tumor, ilepatoprotective, anti-inflammatory, and insecticidal activity.

Extracts of Chinese wormwood also contain a number of volatile oils, including camphor, thujone, cineole, caryophyllene and artemisia ketone. The sesquiterpene lactone artemisinin (qinghaosu) has antimalarial activity both in animals and in vitro. Artemisinin and an active metabolite, dihydroartemisinin, have a rapid action, and parasite clearance times are much shorter than with other antimalarial drugs.

Clinical Trials:

Common Wormwood-Despite the long history of use as an antihelminthic, there are no controlled trials of the crude herb for use in humans. Santonin, isolated from A. absinthium, was re­portedly used effectively for roundworm (Ascaris) infections in the early 20th century; it is no longer used due to significant neurotoxic and other adverse effects. The "bitter" activity of wormwood, applied by herbalists as a digestive stimulant for a variety of gastrointestinal complaints, has not been evaluated in controlled clinical trials for any medical disorder.

Adverse Effects:

Dilute aqueous extracts of common wormwood have few acute side effects other than a bitter taste, which often limits consumption. More concentrated forms, especially pure wormwood oil that contains significant amounts of thujone, have severe toxicity. In one case report, a 31-year-old man mistakenly ingested 10 ml of wormwood oil sold as topical "aromatherapy"; he developed seizures, rhabdomyolysis, and acute renal failure. Abnormalities of hearing and vision, seizures,and brain damage are associated with chronic drinking of absinthe ("absinthism"), although it is unknown to what extent the alcohol content of absinthe contributes to these toxicities.

Artemisinin compounds from Chinese wormwood are genol ally well tolerated, with the incidence of side effects (primarily gastrointestinal) being equivalent to or lower than that of compa rable antimalarial regimens. Of concern is that neurotoxiclly has been demonstrated with high doses of artemisinin agents animal models. There is one case report of chronic cerebellill dysfunction in a patient who self-administered a 5-day course or an oral artemisinin agent for P. falciparum malaria. Rare reports of neurotoxicity, and a potential neurotoxic risk with chronic use, prohibit use of these compounds for malaria prophylaxis in the absence of additional safety data.

Side Effects and Interactions:

Thujone in A. absinthium is a porphyrogenic terpenoid, and may exacerbate bouts of porphyria in patients with this disease.

Cautions:

Ingestion of pure wormwood oil from A. absinthium is absolutely contraindicated, and may be life threatening. Common wormwood should also be avoided in pregnant and breast-feeding women due to the concern over the toxic potential of thujone. There are no specific contraindications to the use of antimalarial artemisinin compounds in pregnant or lactating women, but thero is little data in these populations.

Preparations & Doses:

Common wormwood is prepared from the aerial parts of the flowering plant, and may be administered in tablets, teas, tinctures, and other extracts. Usual doses range from 5-10 drops of a dilute tincture (as an aromatic "bitter") to 1-1.5 g of crude herb brewed as a tea or decoction up to three times daily.The volatile oil is used topically and for aromatherapy.

Artemisinin derivatives from Chinese wormwood are available ill it number of different forms in countries outside the U.S. Artemisinin extracted from the plant can be administered orally. Semi-synthetic derivatives with better water or oil solubility have been developed for intravenous, intramuscular, or rectal use (e.g., artemether, arteether, artesunate, artelenic acid). While dosing regimens vary widely, most successful trials have treated patients for 5-7 days.

Summary Evaluation

Common wormwood may have some efficacy as an antihelmintic, although its clinical effectiveness has not been adequately evaluated. It may also increase gastrointestinal secretions (the "bitter" property of the herb), accounting for its use in mild strointestinal disorders; however, its clinical utility has not been studied and is not well defined in conventional allopathic medicine. The potential neurotoxic effects associated with thujone give this herb a low benefit-to-risk ratio.

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Steve Mathew is a writer, who writes many great articles on herbal medicines for common ailments and diseases. For more information on herbal remedies and home remedies visit our site on health care.

Source: ArticleTrader.com