page_title: Project 523
section_title: Discovery of artemisinin and its derivatives
hierarchical_section_title: Project 523 / Execution and achievements / Discovery of artemisinin and its derivatives
caption_attribution_description: English: Tu Youyou (right) and her tutor Lou Zhicen in China Academy of Chinese Medical Sciences in 1950s. 中文: 20世纪50年代，在中医研究院中药研究所任研究实习员的屠呦呦（右）与老师楼之岑副教授一起研究中药。
context_page_description: Project 523 is a code name for a 1967 secret military project of the People's Republic of China to find antimalarial medications. Named after the date the project launched, 23 May, it addressed an important threat in the Vietnam War: malaria, which claimed more lives than the battles themselves did. At the behest of Ho Chi Minh, Prime Minister of North Vietnam, Zhou Enlai, the Premier of the People's Republic of China, convinced Mao Zedong, Chairman of the Communist Party of China, to start the mass project "to keep [the] allies' troops combat-ready", as the meeting minutes put it. More than 500 Chinese scientists were recruited. The project was divided into three streams. The one for investigating traditional Chinese medicine discovered and led to the development of a class of new antimalarial drugs called artemisinins. Launched during and lasting throughout the Cultural Revolution, Project 523 was officially terminated in 1981.
  For their high efficacy, safety and stability, artemisinins such as artemether and artesunate became the drugs of choice in treating falciparum malaria.
context_section_description: The fourth-century Chinese physician Ge Hong's book Zhouhou Beiji Fang (Chinese: 《肘後備急方》; lit.: The Handbook of Prescriptions for Emergencies) described Artemisia annua extract, called qinghao, as a treatment of malarial fever. Tu Youyou and her team were the first to investigate. In 1971 they found that their extract from the dried leaves (collected from Beijing) did not indicate any antimalarial activity. On careful reading of Ge's description they changed their extraction method of using fresh leaves under low temperature. Ge explicitly describes the recipe as: "qinghao, one bunch, take two sheng [2 × 0.2 l] of water for soaking it, wring it out, take the juice, ingest it in its entirety". Following the findings of scientists at the Yunnan Institute of Pharmacology, they found that only the fresh plant specimen collected from Sichuan province would yield the active compound. They made the purified extract into tablets, which showed very low activity. They soon realized that the compound was very insoluble and made it in capsules instead. On 4 October 1971 they successfully treated malaria in experimental mice (infected with Plasmodium berghei) and monkeys (infected with Plasmodium cynomolgi) using the new extract. In August 1972 they reported a clinical trial in which 21 malarial patients were cured. In 1973 the Yunnan scientists and those at the Shandong Institute of Pharmacology independently obtained the antimalarial compound in a crystalline form gave the name huanghaosu or huanghuahaosu, eventually renamed qinghaosu (yet later to be popularised as "artemisinin", after the botanical name). The same year Tu synthesized the compound dihydroartemisinin from the extract. This compound was more soluble and potent than the native compound. Other scientists subsequently synthesized other artemisinin derivatives, of which the most important are artemether and artesunate. All clinical trials by this time confirmed that artemisinins are more effective than the conventional antimalarial drugs, such as chloroquine and quinine. A group of scientists in Shanghai, including chemist Wu Yulin, determined artemisinin's chemical structure in 1975 and published it in 1977 when the secrecy rules lifted. They are now recognised not only as the most potent but also as the safest and rapidly acting antimalarial drugs.
caption: Tu Youyou (right) and her tutor Lou Zhicen at the China Academy of Chinese Medical Sciences.
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