Artemisinin in the context of "Tu Youyou"

Semisynthesis, or partial chemical synthesis, is a type of chemical synthesis that uses chemical compounds isolated from natural sources (such as microbial cell cultures or plant material) as the starting materials to produce novel compounds with distinct chemical and medicinal properties. The novel compounds generally have a high molecular weight or a complex molecular structure, more so than those produced by total synthesis from simple starting materials. Semisynthesis is a means of preparing many medicines more cheaply than by total synthesis since fewer chemical steps are necessary.

Drugs derived from natural sources are commonly produced either by isolation from their natural source or, as described here, through semisynthesis of an isolated agent. From the perspective of chemical synthesis, living organisms act as highly efficient chemical factories, capable of producing structurally complex compounds through biosynthesis. In contrast, engineered chemical synthesis, although powerful, tends to be simpler and less chemically diverse than the complex biosynthetic pathways essential to life.

Antimalarial medications or simply antimalarials are a type of antiparasitic chemical agent, often naturally derived, that can be used to treat or to prevent malaria, in the latter case, most often aiming at two susceptible target groups, young children and pregnant women. As of 2018, modern treatments, including for severe malaria, continued to depend on therapies deriving historically from quinine and artesunate, both parenteral (injectable) drugs, expanding from there into the many classes of available modern drugs. Incidence and distribution of the disease ("malaria burden") is expected to remain high, globally, for many years to come; moreover, known antimalarial drugs have repeatedly been observed to elicit resistance in the malaria parasite—including for combination therapies featuring artemisinin, a drug of last resort, where resistance has now been observed in Southeast Asia. As such, the needs for new antimalarial agents and new strategies of treatment (e.g., new combination therapies) remain important priorities in tropical medicine. As well, despite very positive outcomes from many modern treatments, serious side effects can affect some individuals taking standard doses (e.g., retinopathy with chloroquine, acute haemolytic anaemia with tafenoquine).

Specifically, antimalarial drugs may be used to treat malaria in three categories of individuals, (i) those with suspected or confirmed infection, (ii) those visiting a malaria-endemic regions who have no immunity, to prevent infection via malaria prophylaxis, and (iii) or in broader groups of individuals, in routine but intermittent preventative treatment in regions where malaria is endemic via intermittent preventive therapy. Practice in treating cases of malaria is most often based on the concept of combination therapy (e.g., using agents such as artemether and lumefantrine against chloroquine-resistant Plasmodium falciparum infection), since this offers advantages including reduced risk of treatment failure, reduced risk of developed resistance, as well as the possibility of reduced side-effects. Prompt parasitological confirmation by microscopy, or alternatively by rapid diagnostic tests, is recommended in all patients suspected of malaria before treatment is started. Treatment solely on the basis of clinical suspicion is considered when a parasitological diagnosis is not possible.

Artemisia annua, also known as sweet wormwood, sweet annie, sweet sagewort, annual mugwort or annual wormwood, is a common type of wormwood native to temperate Asia, but naturalized in many countries including scattered parts of North America.

The chemical compound artemisinin, which is isolated from A. annua, is a medication used to treat malaria due to Plasmodium falciparum, the deadliest species of malarial parasite. Discovery of artemisinin and its antimalarial properties made the Chinese scientist Tu Youyou recipient of the 2011 Lasker Prize and 2015 Nobel Prize in Physiology or Medicine.

1,2,4-Trioxane is one of the isomers of trioxane. It has the molecular formula C₃H₆O₃ and consists of a six membered ring with three carbon atoms and three oxygen atoms. The two adjacent oxygen atoms form a peroxide functional group and the other forms an ether functional group. It is like a cyclic acetal but with one of the oxygen atoms in the acetal group being replaced by a peroxide group.

1,2,4-Trioxane itself has not been isolated or characterized, but rather only studied computationally. However, it constitutes an important structural element of some more complex organic compounds. The natural compound artemisinin, isolated from the sweet wormwood plant (Artemisia annua), and some semi-synthetic derivatives are important antimalarial drugs containing the 1,2,4-trioxane ring. Completely synthetic analogs containing the 1,2,4-trioxane ring are important potential improvements over the naturally derived artemisinins. The peroxide group in the 1,2,4-trioxane core of artemisinin is cleaved in the presence of the malaria parasite leading to reactive oxygen radicals that are damaging to the parasite.