Artemisinin (pronounced /ɑːtə'misinən/) is a drug used to treat multi-drug resistant strains of falciparummalaria. The compound (a sesquiterpene lactone) is isolated from the plant Artemisia annua. Not all plants of this species contain artemisinin. Apparently it is only produced when the plant is subjected to certain conditions, most likely biotic or abiotic stress. It can be synthesized from artemisinic acid. The drug is derived from a herb used in Chinese traditional medicine, though it is usually chemically modified and combined with other medications.
Use of the drug by itself as a monotherapy is explicitly discouraged by the World Health Organization as there have been signs that malarial parasites are developing resistance to the drug. Combination therapies that include artemisinin are the preferred treatment for malaria and are both effective and well tolerated in patients. The drug is also being studied as a treatment for cancer.
Artemisinin History
Artemisia has been used by Chinese herbalists for more than a thousand years in the treatment of many illnesses, such as skin diseases and malaria. The earliest record dates back to 200 BC, in the "Fifty-two Prescriptions" unearthed from the Mawangdui Han Dynasty Tombs. Its antimalarial application was first described in Zhouhou Beji Fang ("The Handbook of Prescriptions for Emergencies"), edited in the middle of the fourth century by Ge Hong. In the 1960s a research program was set up by the Chinese army to find an adequate treatment for malaria. In 1972, in the course of this research, Tu Youyou (Chinese:Artemisia annua (annual wormwood). The drug is named QinghaosuChinese: ) in Chinese. It was one of many candidates then tested by Chinese scientists from a list of nearly 200 traditional Chinese medicines for treating malaria. It was the only one that was effective, but it was found that it cleared malaria parasites from their bodies faster than any other drug in history. Artemisia annua is a common herb and has been found in many parts of the world, including along the Potomac River, in Washington, D.C. discovered artemisinin in the leaves of.
Images of the original scientific papers are available online and a book, Zhang Jianfang, "Late Report – Record of Project 523 and the Research and Development of Qinghaosu", Yangcheng Evening News Publisher 2007), was published in 2006, which records the history of the discovery.
It remained largely unknown to the rest of the world for about ten years, until results were published in a Chinese medical journal. The report was met with skepticism at first, because the Chinese had made unsubstantiated claims about having found treatments for malaria before. In addition, the chemical structure of artemisinin, particularly the peroxide, appeared to be too unstable to be a viable drug.
Artemisinin Cancer treatment
Artemisinin is under early research and testing for treatment of cancer, primarily by researchers at the University of Washington. Artemisinin has a peroxide lactone group in its structure. It is thought that when the peroxide comes into contact with high iron concentrations (common in cancerous cells), the molecule becomes unstable and releases reactive oxygen species. It has been shown to reduce angiogenesisvascular endothelial growth factor in some tissue cultures. and the expression of
Purely synthetic analogues
To counter the present shortage in leaves of Artemisia annua, researchers have been searching for a way to develop artemisinin artificially in the laboratory. A 2006 paper in Nature presented a genetically engineered yeast that can synthesize a precursor called artemisinic acid which can be chemically converted to artemisinin. The compound called OZ-277 (also known as RBx11160), developed by Jonathan Vennerstrom at the University of Nebraska, has proved to be even more effective than the natural product in test-tube trials. A six month trial of the drug on human subjects in Thailand was started in January 2005. There are also plans to have the plant grow in other areas of the world outside Vietnam and China (Kenya, Tanzania, Madagascar).
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