Although she was named head of the group, in many ways, she was a group unto herself. Working alone, she visited senior Chinese medicine practitioners and consulted ancient texts, accumulating over 2,000 prescription recipes in three months. She collected these into a mimeographed pamphlet, A Collection of Single Practical Prescriptions for Anti-Malaria (抗瘧集). It contained more than 640 kinds of traditional Chinese medicines, including Artemisia annua (青蒿).
The group expanded to include three members, beginning with research into herbal medicine. Together, they screened extracted samples from over 100 kinds of Chinese medicines - unfortunately to no avail.
Tu persisted and ordered everyone back to the ancient texts until one day when the unassuming Artemisia annua, a plant from the same family as the sunflower, caught the group’s attention.
Artemisia annua, also known as sweet wormwood, is a very common plant in northern and southern China and had been used in China for more than 2,000 years. The treatment of malaria using Artemisia annua was detailed in the Handbook of Prescriptions for Emergency Treatments (肘後備急方) by Ge Hong (葛洪) during the Eastern Jin Dynasty. Later records in the Song, Yuan and Ming dynasties described the drug in potion, pill and powder form. There was also a record describing the treatment of malaria in the Bencao Gangmu (The Compendium of Materia Medica,本草綱目).
Although many Chinese medicine practitioners at that time were familiar with the idea of using the plant to treat malaria, they did not have access to the scientific methods Tu utilized to synthesize a standard, replicable, reliable treatment.
Tu’s working conditions at the time were spartan, equipment was simple and the team lacked the necessary ventilation system and protections, such that Tu contracted toxipathic hepatitis while extracting the needed compound. Her husband, Li Tingzhao (李廷釗), recalls that during that period, his wife would cloister herself in the lab with only artemisinin on her mind.
Later inspired by a re-reading of Ge Hong’s Handbook, Tu and her colleagues changed the method of extracting the drug, carrying out a series of complex and tedious screening procedures. After 190 failures, they experienced a breakthrough on the 191st attempt.
On October 4, 1971, Tu was successful in extracting an effective compound from Artemisia annua using low-temperature ether (instead of boiling water, which was found to damage the compound). Tests of its effectiveness against Plasmodium, the parasite that causes malaria, were shown to be 100% successful in animals.
To ensure the safety of the treatment, Tu volunteered to be the first human test subject. She then went to hot-weather Hainan Island where malaria was particularly rampant to conduct the first clinical trial. On November 8, 1972, Qinghaosu (the Chinese name for artemisinin) was born. In the year that followed, Tu would also discover dihydroartemisinin, the first of many other malaria treatments based on artemisinin.
A Gift
Before the advent of artemisinin, about 400 million people worldwide suffered from malaria annually with one million cases proving fatal.
The disease’s resistance to drugs withstanding, the previously leading malaria treatment quinine also caused dizziness, tinnitus and palpitations, and many patients described the side effects of quinine as more painful than the disease. As such, artemisinin, with its mild medicinal properties and low side effects, has become a life-saving medicine for hundreds of millions of people. For this reason, artemisinin-derived drugs have since become a required gift accompanying Chinese leaders visiting Africa, where they are known simply as "Chinese medicine" in some local areas.
In 2004, the World Health Organization listed artemisinin-based drugs as the treatment of choice for malaria. Since 2000, one billion people across the globe have benefited from artemisinin-based combination therapy (ACT) with about 240 million people in sub-Saharan Africa having received therapy that includes artemisinin. This has led to the prevention of 1.5 million malaria-related deaths, particularly in children.
In the case of the Comoros Islands in the Indian Ocean, the number of malaria cases in 2006 were 108,000. In 2007, China collaborated with the Comoros government to implement artemisinin in an attempt to eradicate malaria from the country. In 2014, the Comoros had zero deaths from malaria, and the number of cases decreased to just over 2,000, a decrease of 98%. During this period, the Comoros successfully transitioned from being designated a high-endemic area of malaria to being a low-endemic area.
Matshidiso Moeti, Director of the WHO Regional Office for Africa, was quoted as saying the contribution of artemisinin to reducing deaths from malaria is evident in Africa, where many of the tens of thousands killed by malaria every year are children. With artemisinin, the continent is better placed to achieve the United Nations Millennium Development Goals.
In 2011, Tu Youyou received the Lasker-DeBakey Clinical Medical Research Award, bringing the relatively unknown scientist to the world’s attention. After the award, Tu remained very calm, repeatedly stressing: "This is not my honor alone, but the honor of all Chinese scientists." Four years later, on October 5, 2015, she was awarded the 2015 Nobel Prize in Physiology or Medicine, together with two other parasitologists, at the Karolinska Institute of Sweden. Tu Youyou is the 12th female winner of the Nobel Prize in Medicine in the history of the prize.
