Artemisia annua

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Artemisia annua
Scientific classification
Kingdom:Plantae
(unranked):Angiosperms
(unranked):Eudicots
(unranked):Asterids
Order:Asterales
Family:Asteraceae
Genus:Artemisia
Species:A. annua
Binomial name
Artemisia annua
L.
 
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Artemisia annua
Scientific classification
Kingdom:Plantae
(unranked):Angiosperms
(unranked):Eudicots
(unranked):Asterids
Order:Asterales
Family:Asteraceae
Genus:Artemisia
Species:A. annua
Binomial name
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 native to temperate Asia, but naturalized throughout the world.

Characteristics[edit]

It has fern-like leaves, bright yellow flowers, and a camphor-like scent. Its height averages about 2 m, and the plant has a single stem, alternating branches, and alternating leaves which range from 2.5–5 cm in length. It is cross-pollinated by wind or insects. It is a diploid plant with chromosome number 2n=18.[1][2]

Medicinal uses[edit]

Folk medicine[edit]

In traditional Chinese medicine, A. annua is categorized as a herb of the "heat-clearing" category.[3]

Extractions[edit]

In 1971, scientists demonstrated 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.[4]

Malaria treatment[edit]

Artemisia annua

Research to develop antimalarial drugs led to the discovery artemisinin, which is extracted from Artemisia annua.[5] Scientists started by studying traditional recipes, but found that by moving away from them and using a low-temperature ether-based extraction method, and by adding detoxification and purification processes, they could create a drug with sufficient active ingredient to be effective.[6]

Artemisinin is a sesquiterpene lactone with an endoperoxide bridge and has been produced semisynthetically 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 treat malaria.[7][8][9] In 2004, the Ethiopian Ministry of Health changed Ethiopia's first line antimalaria drug from sulfadoxine/pyrimethamine (Fansidar), which has an average 36% treatment failure rate, to artemether/lumefantrine (Coartem), a drug therapy containing artemesinin which is 100% effective when used correctly, despite a worldwide shortage at the time of the needed derivative from A. annua.[10] A 2012 review said that artemisinin-based remedies are the most effective drugs for the treatment of malaria.[11]

As of 2013, it seems that the pathogenic agent of malaria is slowly becoming resistant to artemisinin-based drugs.[12]

Mechanism[edit]

Seeds

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.[13] Malaria is caused by apicomplexans, primarily Plasmodium falciparum, which largely reside in red blood cells and itself contains iron-rich heme-groups (in the form of hemozoin).[14]

References[edit]

  1. ^ 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:10.1007/BF02803203. 
  2. ^ Rotreklová, O.; P. Bure; V. Grulich (2004). "Chromosome numbers for some species of vascular plants from Europe". Biologia, Bratislava 59 (4): 425–433. 
  3. ^ Dharmandanda, S. "CHING-HAO and the Artemisias Used in Chinese Medicine". Institute for traditional medicine. 
  4. ^ Duke SO, Paul RN (1993). "Development and Fine Structure of the Glandular Trichomes of Artemisia annua L.". Int. J Plant Sci. 154 (1): 107–18. doi:10.1086/297096. JSTOR 2995610. 
    Ferreira JFS, Janick J (1995). "Floral Morphology of Artemisia annua with Special Reference to Trichomes". Int. J Plant Sci. 156 (6): 807. doi:10.1086/297304. 
  5. ^ Miller, L.H.; Su, X. (2011). "Artemisinin: Discovery from the Chinese Herbal Garden". Cell 146: 855–58. 
  6. ^ Miller, L.H.; Su, X. (2011). "Artemisinin: Discovery from the Chinese Herbal Garden". Cell 146: 855–58. 
  7. ^ 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 (5): 318–21. doi:10.1016/j.trstmh.2003.09.001. PMID 15109558. 
  8. ^ Räth K, Taxis K, Walz GH, et al. (1 February 2004). "Pharmacokinetic study of artemisinin after oral intake of a traditional preparation of Artemisia annua L. (annual wormwood)". Am J Trop Med Hyg 70 (2): 128–32. PMID 14993622. 
  9. ^ 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:10.1016/j.trstmh.2005.08.004. PMID 16274712. 
  10. ^ "Malaria Update", Focus on Ethiopia, April 2005, UN-OCHA website (accessed 12 March 2009)
  11. ^ Fairhurst, RM; Nayyar, GM; Breman, JG; Hallett, R; Vennerstrom, JL; Duong, S; Ringwald, P; Wellems, TE; Plowe, CV; Dondorp, AM (2012). "Artemisinin-resistant malaria: Research challenges, opportunities, and public health implications". The American journal of tropical medicine and hygiene 87 (2): 231–41. doi:10.4269/ajtmh.2012.12-0025. PMC 3414557. PMID 22855752. 
  12. ^ News published on the Center for Strategic and International Studies website (Nov. 7, 2013)
  13. ^ Cumming JN; Ploypradith P; Posner GH (1997). "Antimalarial activity of artemisinin (qinghaosu) and related trioxanes: mechanism(s) of action". Adv. Pharmacol. 37: 253–97. PMID 8891104. 
  14. ^ 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 (6): 397–404. doi:10.1021/ar020227u. PMID 15196049. 

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