June 23, 2024

I, Science

The science magazine of Imperial College

By Wen Xin Kang
18th February 2022

On a historic day last October, the World Health Organisation endorsed the world’s first malaria vaccine, sparking hope for millions of Africans who have grown up with the disease. Worldwide, 241 million malaria infections and 627,000 deaths were recorded in 2020. These are huge numbers, but they hide a staggering 47% drop in cases since 2000. How was this achieved? The answer lies in a top-secret mission and Traditional Chinese Medicine.

Malaria is a life-threatening disease transmitted via the bite of the female Anopheles mosquito. The Plasmodium parasite hops from one host to the other, leading to acute illness in humans if left untreated. Infected patients experience a fever and flu-like sickness with symptoms ranging from vomiting to chills and muscle ache. In severe cases, malaria causes anaemia and jaundice, which is the yellow colouring of the skin and eyes. This happens when Plasmodium enters the blood and infects red blood cells, drastically reducing their number.

Efforts to develop anti-malarial drugs to prevent and treat infection started in the 1940s. Drugs like chloroquine target the parasite before it can invade the red blood cells. Shortly after it was introduced, however, chloroquine-resistant Plasmodium started to spread in some regions of Southeast Asia, Oceania and South America. In the late 1950s and early 1960s, these resistant strains wiped out innumerable combat units fighting in the Vietnam War. In the face of these losses, the North Vietnamese government felt it had no choice but to turn to China for a miracle drug.

In response to the North Vietnamese government’s plea, China set up a top-secret state mission known as Project 523. The aim of was to identify new drug treatments to overcome chloroquine-resistant malaria. In an effort to validate and promote its benefits, Project 523 embraced the traditional body of knowledge of Chinese medicine. Much of the project focused on furthering knowledge of the healing properties of substances via selective appropriation and detailed investigations.

It was during this time that Tu Youyou was appointed as head of the malaria research group, leading a team of phytochemical and pharmacological researchers. Together, they turned to ancient medical texts to gain a better understanding of the traditional Chinese treatments for malaria. They screened more than 2,000 Chinese herbs by extracting and isolating the substances with potential anti-malarial properties. Through this arduous process they identified 640 promising herbs, but no definitive conclusions were reached. 

Then, Professor Tu made a discovery which would change the course of history. The key to the success of Project 523 was a herb called Artemisia annua, which was found to inhibit parasitic growth, including the parasite Plasmodium. It still wasn’t smooth sailing at this point because Professor Tu’s observations could not be replicated in subsequent experiments. Chasing after the solution to the malarial conundrum, Professor Tu turned to the only relevant reference to Artemisia annua: Ge Hong’s “Handbook of Prescriptions for Emergencies”.

In this handbook, Professor Tu found a series of steps to alleviate the symptoms of malaria with artemisinin. What struck her was that Ge Hong made no mention of heating the plant to extract the healing substance. This gave her an idea: perhaps the heating step in the conventional extraction process was breaking down the anti-malarial component. Indeed, when she skipped the heating step, the artemisinin extract proved successful in treating mice and monkeys infected with Plasmodium. This discovery spurred Professor Tu on to investigate further.

The crux of the matter was whether artemisinin would be as effective in treating humans. During the Cultural Revolution in China in the 1970s, there were no means to perform clinical trials for new drugs. Valiantly, Professor Tu and her team volunteered themselves for a trial before treating 21 patients infected with malaria using artemisinin. Every single one of them was cured.

In 1981, the WHO, World Bank and United Nations each invited Professor Tu to present her ground-breaking findings on the global stage. In 2015, she became the first woman from China to be awarded a Nobel Prize in medicine. Professor Tu’s work showcased the benefit of integrating traditional knowledge, specifically Traditional Chinese Medicine, with formal scientific methods. A way forward in medicine is to bridge the gap between Traditional Chinese Medicine and Western medicine to better understand and improve human health.

In the words of Tu Youyou: “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.”

Wen Xin Kang is a contributing writer for I, Science. She is currently a penultimate Medical Bioscience (BMB) student at Imperial. Wen Xin is particularly interested in pursuing science communication and life science consulting in the future.