Artemisinin

Artemisinin is an antimalarial drug and a sesquiterpene lactone. Its defining structural feature is an endoperoxide bridge set within a trioxane ring, a chemically unusual arrangement that is essential to its activity against malaria parasites. It is obtained from the leaves of Artemisia annua, the sweet wormwood plant.

The plant, known in Chinese medicine as qinghao, had been used for centuries to treat fevers. During a Chinese research effort in the 1960s and 1970s known as Project 523, the pharmacologist Tu Youyou and colleagues screened traditional remedies and, drawing on an ancient text, isolated the active antimalarial compound and developed a low-temperature extraction that preserved its activity ^[1]. Tu was awarded a share of the 2015 Nobel Prize in Physiology or Medicine for this discovery ^[1].

Artemisinin and its derivatives act very rapidly against the malaria parasite, quickly reducing the number of parasites in the blood. To protect their effectiveness and slow resistance, the World Health Organization recommends they be given as artemisinin-based combination therapies (ACTs), pairing a fast-acting artemisinin drug with a longer-lasting partner medicine. ACTs are the standard treatment for uncomplicated Plasmodium falciparum malaria, the most dangerous form, across the world.

Because artemisinin itself is poorly soluble, several semisynthetic derivatives with better properties are used clinically, including artesunate, artemether, and dihydroartemisinin. Supply once depended entirely on cultivation of the plant, but researchers later engineered yeast to produce a chemical precursor of the drug, offering a route to semisynthetic artemisinin to help stabilize supply ^[4].

A serious concern is the emergence of partial artemisinin resistance, first detected in Southeast Asia, in which parasites clear more slowly from the blood. Researchers identified mutations in the parasite's kelch13 gene as a molecular marker of this resistance, a finding important for tracking its spread ^[3]. Artemisinin-based drugs are prescription antimalarials, and safeguarding their effectiveness through combination therapy and surveillance remains a global public-health priority ^[2].

In supervised antimalarial use it's generally well tolerated, but supplement use is another matter. Possible effects include GI upset, and rare liver enzyme elevations or allergic reactions. It should not be used in pregnancy, especially the first trimester. Casual or monotherapy use is discouraged because it can drive drug resistance in malaria; anyone considering it for a medical purpose should work with a clinician.