Pharmacological properties: Artemisinin acts as a blood schizontocide and kills therefore malaria parasites.Artemisinin is the product extracted from the dry leaves of Artemsisia Annua (sweet wormwood). This plant has to be grown each year stating from seeds. The plant is peculiar in its behaviour. Nicely grown-up plants may be devoid of Artemisinin. In order that this product is synthetised by the plant special agricultural conditions must be respected. The plant can grown in many places but it may not contain Artemisinin.For example: Visitors of the ancient palaces in the Forbidden City in Beijing can find nice artemisia annua plants pushing left and right as weeds, but these plants do not contain artemisinin.Best results have been obtained in plantations (North Vietnam, mainly in the vicinity of Hanoi) or in wild plants (the plants collected from the steep hills around You Young in the Chongqing province in China where the plant grows at altitudes above 1400 m).Artemsia annua is a plant with a strong parfum. It contains camphor and essential oils. It is a strong plant. Once it has started on its full development it can survive a hot climate and long dry spells. The roots penetrate very deep. The plant needs to be harvested before the flowering starts since this decreases the content of Artemisinin. In optimal conditions 1 hectare will yield 1-2 tons of Artemisia leaves. Every ton gives 2-3 kg Artemisinin. Wild plants, as grown in Central China give similar results but others do not and some do not even have artemsinin inside. The origin of Artemisinin as antimalarial drug:Wars have many times led to the development of new technology but also of new medicaments.The antimalarial drugs are typical examples.Chloroquin resulted from the second world war.Mefloquin resulted from the Vietnam war at the side of the Americans.
What many do not know :

Artemisnin also results from the Vietnamese war. When this war was raging in the seventies, many Vietnamese soldiers died from malaria caused by parasites resistant to the currently used medicaments. Ho Chi Minh, the Vietnamese leader, asked for help from his Chinese neighbour. Mao offered very genereously his help and he organised a large scale research for new and better drugs. Many scientist in many places were involved. Succes was not forthcoming until one day a researcher had the splendid idea to extract a medicinal plant (Artemisia Annua) with hexane. This had not been done before. All preparations with this medicinal herb were based on the use of the leaves as such or on aqueous extractions. So the extraction with hexane led to discoveries totally unknown to the Chinese scientists. Not many details are left over from those pioneering days. But the scientist extracted a yellowish oily substance. After purifications over silica gel and by repeated axtractions he finally obtained a crystalline substance. It was named Artemisinin (Quing gha shu). This powder had the unique property that it could be used to kill the schizonts of the malaria parasite. The difficulties were not over with this discovery. Analysis showed that the new substance was probably a unique compound. It showed a brutoformula of C15H23O5 and this puzzled all scientists in the group. Nobody could elucidate the structure.Which sort of structure could have 5 oxygen atoms?It took years before the problem became solved. X-ray crystallographic analyses indicated the unique structure of this cesquiterpene having 5 oxygen atoms, 2 of them in a peroxide bridge system over a seven membered ring and 2 involved in a lactone ring structure. The unique stereoconfiguration became established. Artimisinin has no less than 9 centers of assymetry allowing for a multitude of theoretical configurations. But luckily Artemisia annua makes only one configuration. And until now only one has been found which makes identification work a lot easier.After structure elucidation it became obvious that structure adaptation would lead to more stable molecules and to derivatives more suitable for pharmaceutical and therapeutic applications. The stereospecificity of this molecule makes total synthesis very difficult and certainly not adaptable to industrial productions at acceptable price level.