Artemisinin and Tu Youyou: A Drug Found Through Traditional Texts

Urgent note first

Malaria is a medical emergency. The World Health Organization (WHO) says early symptoms are fever, headache and chills, and that untreated falciparum malaria can progress to severe illness and death within 24 hours. [1] If you have a fever after travel to or time in an area with malaria, get medical care promptly. Do not treat it with herbal tea. WHO does not support the promotion or use of Artemisia plant material in any form for the prevention or treatment of malaria. [2]

Why this story matters

Artemisinin is the clearest example of a medicine developed with help from a traditional Chinese source. In 2015 the Nobel Prize in Physiology or Medicine was shared: the other half went to Tu Youyou for her discoveries concerning a novel therapy against malaria (half went jointly to William Campbell and Satoshi Omura for a different parasite treatment). [3] The story shows both what traditional texts can offer and the work needed to turn a lead into a drug.

The problem Tu Youyou was asked to solve

By the late 1960s efforts to eradicate malaria had failed and the disease was on the rise. [3] Resistant strains of the malaria parasite to chloroquine had emerged and spread. [4] Tu and her team worked as part of a large national project in China to develop new malaria therapies. [4]

From texts to a candidate plant

• Screening. Tu turned to traditional herbal medicine, and a large-scale screen of herbal remedies in malaria-infected animals produced an extract of the plant Artemisia annua (sweet wormwood) as an interesting candidate. [3] The Nobel committee notes the plant stood out because it appeared in several hundred recipes. [4]
• A setback. Results were inconsistent: later experiments showed only 12 to 40 percent inhibition of rodent malaria parasites. [4]
• A clue from the text. Tu revisited older literature and, in recipes attributed to Ge Hong (dated by the Nobel committee to 340 AD), found a description of obtaining "juice" from the leaves using cold water instead of the traditional boiling method. [4]
• The method change. That inspired a low-temperature extraction with ether rather than the earlier ethanol method. With it, Tu achieved consistent results, killing 100 percent of malaria parasites in infected mice and monkeys. [4]

From extract to medicine

• Human testing. Tu undertook clinical tests and found that the plant extract rapidly reduced fever and decreased the number of parasites in the blood of malaria patients. [4]
• Purified compound. The active component, later called artemisinin, was shown highly effective against the malaria parasite. [3] Artemisinin was first isolated and tested in the 1970s in China, according to Tu's own Nobel lecture. [5]
• Mechanism. The Nobel committee says the mechanism of action is not entirely known, though evidence suggests the Kelch 13 protein is involved. [4]

Where it stands today

WHO says artemisinin-based combination therapy medicines are the most effective treatment for P. falciparum malaria. [1] WHO is also very concerned about confirmed partial artemisinin resistance in Eritrea, Rwanda, Uganda and the United Republic of Tanzania. [1] The medicine is given as a combination therapy, while WHO does not support using the plant material itself. [1][2]

What this does and does not show

The lesson is about method, not about any one tradition's authority. Tradition provided a lead; laboratory chemistry, animal studies, human tests and regulation made it a medicine. The same path is needed for any other herb. Related examples are on Arsenic Trioxide, Huperzine and Other Drugs With Traditional Sources. The wider question is answered in Does Traditional Chinese Medicine Work?, and the history behind the texts is in History of Traditional Chinese Medicine. Safety around herbs is on Natural and Traditional Do Not Mean Safe.