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| Artemisia annua L. |
Artemisia annua, also known as Sweet Wormwood, Sweet Annie, Sweet Sagewort or Annual Wormwood (Chinese: 青蒿; pinyin: qīnghāo), is a common type of wormwood that grows throughout the world.
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Characteristics
It has fern-like leaves, bright yellow flowers, and a camphor-like scent. Its height averages about 2 m tall, and the plant has a single stem, alternating branches, and alternating leaves which range 2.5-5cm in length. It is cross-pollinated by wind or insects. It is a diploid plant with chromosome number, 2n=18.[1][2]
Medicinal uses
Sweet Wormwood was used by Chinese herbalists in ancient times to treat fever, but had fallen out of common use, but was rediscovered in 1970 when the Chinese Handbook of Prescriptions for Emergency Treatments (340 AD) was found. This pharmacopeia contained recipes for a tea from dried leaves, prescribed for fevers (not specifically malaria).
Extractions
In 1971, scientists demonstrated that the plant extracts had antimalarial activity in primate models, and in 1972 the active ingredient, artemisinin (formerly referred to as arteannuin), was isolated and its chemical structure described. Artemisinin may be extracted using a low boiling point solvent such as diethylether and is found in the glandular trichomes of the leaves, stems, and inflorescences, and it is concentrated in the upper portions of plant within new growth.citation needed
Parasite treatment
It is commonly used in tropical nations which can afford it, preferentially as part of a combination-cocktail with other antimalarials in order to prevent the development of parasite resistance.
Malaria treatment
Artemisinin itself is a sesquiterpene lactone with an endoperoxide bridge and has been produced semi-synthetically as an antimalarial drug. The efficacy of tea made from A. annua in the treatment of malaria is contentious. According to some authors, artemesinin is not soluble in water and the concentrations in these infusions are considered insufficient to treatment malaria.[3][4][5] Other researchers have claimed that Artemisia annua contains a cocktail of anti-malarial substances, and insist that clinical trials be conducted to demonstrate scientifically that artemisia tea is effective in treating malaria.citation needed This simpler use may be a cheaper alternative to commercial pharmaceuticals, and may enable health dispensaries in the tropics to be more self-reliant in their malaria treatment. James Duke and Mike Benge et al, Chemical and Engineering News, Letters, Vol 83, No 18, pp4-5.[6]
Cancer treatment
The plant has also been shown to have anti-cancer properties. It is said to have the ability to be selectively toxic to some breast cancer cells [Cancer Research 65:(23).Dec 1, 2005] and some form of prostate cancer, there have been exciting preclinical results against leukemia,[7] and other cancer cells.
Mechanism
The proposed mechanism of action of artemisinin involves cleavage of endoperoxide bridges by iron producing free radicals (hypervalent iron-oxo species, epoxides, aldehydes, and dicarbonyl compounds) which damage biological macromolecules causing oxidative stress in the cells of the parasite.citation needed Malaria is caused by the Apicomplexan, Plasmodium falciparum, which largely resides in red blood cells and itself contains iron-rich heme-groups (in the from of haemozoin).[8]
Other uses
In modern-day central China, specifically Hubei Province the stems of this wormwood are used as food in a salad-like form. The final product, literally termed "cold-mixed wormwood" is a slightly bitter salad with strong acid overtones from the spiced rice vinegar used as a marinade. It is considered a delicacy and is typically more expensive to buy than meat.
References
- ^ Kreitschitz, A.; J. Vallès (September 2003). "New or rare data on chromosome numbers in several taxa of the genus Artemisia (Asteraceae) in Poland". Folia Geobotanica 38 (3): 333-343. doi:.
- ^ Rotreklová, O.; P. Bure and V. Grulich. "Chromosome numbers for some species of vascular plants from Europe". Biologia, Bratislava 59 (4): 425-433.
- ^ Mueller MS, Runyambo, Wagner I, et al. (2004). "Randomized controlled trial of a traditional preparation of Artemisia annua L. (Annual Wormwood) in the treatment of malaria". Trans R Soc Trop Med Hyg 98: 318–21. doi:.
- ^ Räth K, Taxis K, Walz GH, et al. (2004). "Pharmacokinetic study of artemisinin after oral intake of a traditional preparation of Artemisia annua L. (annual wormwood)". Am J Trop Med Hyg 70: 128–32.
- ^ Jansen FH (2006). "The herbal tea approach for artemesinin as a therapy for malaria?". Trans R Soc Trop Med Hyg 100 (3): 285–6. doi:.
- ^ anamed.net
- ^ ncbi.nlm.nih.gov
- ^ Gary H. Posner & Paul M. O’Neil (2004). "Knowledge of the Proposed Chemical Mechanism of Action and Cytochrome P450 Metabolism of Antimalarial Trioxanes Like Artemisinin Allows Rational Design of New Antimalarial Peroxides". Acc. Chem. Res. 37: 397–404. doi:.
External links
- Scientific information about the plant
- University of Washington article regarding anti-cancer properties
- Anamed.net Charity that trains people in the Tropics to cultivate Artemisia annua and to use their harvest in the form of tea to treat malaria and other diseases, as practiced in China for centuries.
- Distribution of Artemisinin in Artemisia annua
- Artemisinin induces apoptosis in human cancer cells
- Project to improve artemesinin yield at the University of York (UK)
Wikipedia content modification information:
- This page was last modified on 14 October 2008, at 12:31.
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