Yaoyao Tu, now age 84, graduated in 1955 from the Department of Pharmaceutical Sciences of Beijing Medical University and later trained in Traditional Chinese Medicine for three years from 1959 to 1962. Since then, she was involved in research on Chinese herbal medicine in the China Academy of Chinese Medical Sciences.
Tu learn Chinese herb from her tutor Zhicen Lou
Malaria, a tropical parasitic disease, has been with humankind for as long as we know. It is a mosquito-borne disease caused by single-cell parasites, which invade red blood cells, causing fever, and in severe cases brain damage and death. More than 3.4 billion of the world’s most vulnerable citizens are at risk of contracting malaria, and each year it claims more than 450 000 lives, predominantly among children.
The Secret Project 523
Malaria was traditionally treated by chloroquine or quinine, but with declining success. The parasites develo
ped resistance to chloroquine. By the late 1960s, malaria was on the rise. It was taking a heavy toll on the armies of North Vietnam, China’s communist ally. In 1967, Tu was recruited to Chairman Mao’s top-secret Project 523 to investigate cures for malaria.
Tu led a group comprising both phytochemical and pharmacological researchers. Initially, they investigated more than 2,000 Chinese herb preparations and identified 640 hits that had possible antimalarial activities. Qinghao or Artemisia annua (a.k.a. “sweet wormwood” or “sweet mugwort”) was one of the herbal candidates. More than 380 extracts obtained from over 200 Chinese herbs were evaluated against a mouse model of malaria. However, there was no promising or consistent result in sight.
Perseverance Paid Off
Tu began reviewing some 2,000 ancient herbal recipes from the Academy of Traditional Chinese Medicine in Beijing. One of them, written in a 1,600 year old text called “Emergency Prescriptions Kept Up One’s Sleeve”, recommended soaking Qinghao in water and then drinking the resulting juice.
Inspired by this old text, Tu thought that the traditional high temperature water extraction of Qinghao could have destroyed its active ingredients, so she switched to a low temperature ether extraction method. Tried out first on mice and monkeys, it proved highly effective.
Next they had to test if it was harmful to humans. Tu and her colleagues volunteered to be the first test subjects. After ascertaining that the extract was safe for human consumption, they proceeded to test its clinical efficacy on patients infected with malaria. These clinical trials produced outstanding results: patients treated with the extract experienced rapid disappearance of symptoms, whereas patients receiving chloroquine did not.
Encouraged by the clinical outcome, they moved on to investigate the isolation and purification of the active components from Artemisia. In 1972, they identified a colorless, crystalline substance with a molecular weight of 282 Da, a molecular formula of C15H22O5, and a melting point of 156–157 °C as the active component of the extract. They named it Qinghaosu (or artemisinin; su means “basic element” in Chinese).
From Herb to Drug
Tu also found that the leaves contained the most significant amount of the active ingredients. From here, the team continued their effort in turning the effective molecule into a drug. It was a long road to success. (Read this excellent article “2015 Nobel to Traditional Chinese Medicine Expert is a Win for Evidence-based Pharmacognosy” if you are interested in the entire process.)
Malaria infects close to 200 million individuals yearly. Artemisinin is now used in all malaria-ridden parts of the world. It rapidly kill the malaria parasites at an early stage of their development, which explains its unprecedented potency. When used in combination therapy, it is estimated to reduce mortality from malaria by more than 20% overall and by more than 30% in children. For Africa alone, this means that more than 100,000 lives are saved each year.
Recognition and Awards
In 2011, Tu received the Lasker-DeBakey Medical Research Award for “the discovery of artemisinin, a drug therapy for malaria that has saved millions of lives across the globe, especially in the developing world.”
In 2015, Tu shared the Nobel Prize in Medicine with William C Campbell and Satoshi Omura for discoveries that assisted the treatment of infections caused by roundworm parasites and malaria. “They have transformed the treatment of parasitic diseases.The global impact of their discoveries and the resulting benefit to mankind are immeasurable.”
Gifts from old Chinese Medicine
In her Lasker Award acceptance speech, Tu emphasized that Artemisinin is a true gift from old Chinese medicine. She listed examples of a few other Chinese herbs that can potentially solve certain challenging diseases that humans are facing. She concluded, “The examples cited here represent only a sliver of the gifts or potential gifts Chinese medicine has to offer. It is my dream that Chinese medicine will help us conquer life-threatening diseases worldwide, and that people across the globe will enjoy its benefits for health promotion.”
- The Nobel Assembly Karolinska Institutet. Press Release 2015-10-05. http://www.nobelprize.org/nobel_prizes/medicine/laureates/2015/press.html
- Kausik Datta. 2015 Nobel to Traditional Chinese Medicine Expert is a Win for Evidence-based Pharmacognosy. http://www.scilogs.com/in_scientio_veritas/2015-nobel-pharmacognosy/
- Yaoyao Tu. The discovery of artemisinin (qinghaosu) and gifts from Chinese medicine. Nature Medicine 17, 1217–1220 (2011). http://www.nature.com/nm/journal/v17/n10/full/nm.2471.html
- 屠呦呦诺奖报告演讲全文 http://www.gov.cn/zhuanti/2015-12/18/content_5025361.htm