Artemisinin
A drug for multi-drug resistant strains of falciparum malaria. The compound (an sesquiterpene lactone) is isolated from the shrub Artemisia annua. Not all shrubs of this species contain artemisinin. Apparently it only is produced by the plant when the plant is subjected to certain conditions.
Chemically it is (3R,5aS,6R,8aS,9R,12S,12aR)-octahydro-3,6,9-trimethyl-3,12-epoxy-12H-pyrano[4,3-j]-1,2-benzodioxepin-10(3H)-one, C15H22O5.
History
It was first discovered in China in 1972. The drug is named qinghaosu 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.
It remained largely unknown to the rest of the world for about 10 years, due to the Communist Chinese government at the time. The rest of the world finally found out about the drug from an article in a Chinese medical journal. People were sceptic at first, because the Chinese had made earlier statements about having found treatments of malaria before, but these were unsubstantiated. Another reason was the peroxide part of the molecule. It was thought unlikely this would be a stable molecule, and so would not last long enough to be effective. This turned out not to be the case.
The Chinese government at the time, however, was very wary of western scientists, and would not give anyone either the plant or the refined drug. People around the world now started looking for the shrub themselves, to see if they could find it. They finally found it along the Potomac river, in Washington, D.C. Apparently it was a very common shrub, found in many parts of the world. It took another 10 years of research before the drug was finally commercially available. By this time relations between Communist China and the rest of the world had improved, and scientific information could be exchanged.
The drug is these days used in China and Vietnam without much regard to taking precautions for maybe creating resistance of the malaria parasite to this drug as well.
How it works
The compound has a double oxygen in its structure. When the double oxygens come into contact with high iron concentrations, the molecule becomes unstable and "explodes" into free radicals. High concentrations of iron are found in red blood cells, which is also where the malaria parasites are found. When the compound enters the red blood cell, it will release the free radicals, which are highly destructive to the parasites.
See also
