The controversial history of the discovery of artemisinin: the most effective antimalarial on the planet.

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The use of the antimalarial drug artemisinin, a sesquiterpene lactone extracted from the glandular trichomes from the plant Artemisia annua, was described for the first time in the Handbook of prescriptions for emergencies, edited by the middle of the 4th century by Ge Hong, Chinese scholar who devoted a large part of his studies to the discovery of physical immortality.

 

Portrait of the Chinese scholar Ge Hong.

In the manual details 43 treatments for malaria.

However, their oldes tuse dates back to the year 200 BC, time of the Han dynasty. 

This was initialled for posterity in the book made of silk, shown in the cover photo, called “Recipes for fifty-two diseases“, which is one of the texts found in the year 1973 at the site of Mawangdui, southeast of china, along with the mummies of the marriage of marquises of Dai and his son.

During the Han Dynasty, flourished the intellectual achievements, artistic and literary of China, developed then there one of the great inventions of history: the paper.

This is how these older works of the traditional Chinese medicine connect with one of the great discoveries of the 20th century. And this is how it was continued the research on the antimalarial properties of the artemisinin:

It was in 1967 when the People’s Liberation Army created a research program under the name of Project 523, with the aim of finding an appropriate treatment for malaria.

The program and its initial clinical studies were ordered by the leader Mao Zedong at the request of the leaders of North Vietnam, to control outbreaks of epidemics in their army.

In the course of the investigations, Dr. Tu Youyou, which was a doctor and pharmaceutical chemist, discovered the properties of the antimalarial artemisinin, serving as a guide the previous ancient texts of traditional Chinese medicine.

They described, for example, the extraction process at low temperature of this powerful Antimalarial.

The compound was one of the many candidates tested by Chinese scientists as potential treatments for malaria, a list of nearly 500 traditional Chinese medicines.

In addition to the artemisin, the Project 523 developed a number of products that can be used along with this active principle, including the lumefantrine, the piperaquine and pyronaridine.

After her discovery, for almost a decade and a half the Chinese government restricted access to the purified drug and the plant from which it was removed.

It was not until 1979, in full chinese economic reform, that news of the discovery came to scientists of other nationalities through results published in the scientific journal Chinese Medical Journal .

The investigation was received with skepticism at first, in part because the chemical structure of the artemisinin, particularly the portion peroxid, seemed to be as too unstable to be a viable medicine .

Ying Lee, one of the scientists involved in the research of artemisinin, said that China, in the middle of the cold war, didn´t want to show to the west, and of special way to United States their medical and pharmacological advances for strategic reasons.

At the end of 1990, the Switz biotech and pharmaceutical company Novartis bought a new chinese patent for a combined treatment with artemether and lumefantrine, providing the first artemisinin-based combination therapy (Coartem) at reduced prices to the World Health Organization.

In 2006, when the artemisinin began to be the global reference treatment for malaria, WHO called for a brake to preparations of artemisinin-based combination therapy based on a single active principle, so that will be managed with other medications and combinations of artemisinin derivatives against malaria. This reduced the risk of parasites to develop resistance.

In 2011Tu Youyou was awarded with the Albert Lasker Award for Clinical Medical Research for her role in the discovery and development of artemisinin , and in 2015 with half of the Nobel Prize in Physiology or Medicine, which she shared with the scientists Satoshi Omura and William Campbell, whom had discovered a new compound, the avermectin, able to cure infections such as onchocerciasis and lymphatic filariasis caused by tiny parasites.​

In 2012, a study reported that artemisinin-based combination therapies were most effective in the treatment of malaria and also that eliminated faster plasmodium parasites of the patient’s body than other drugs.

 

The discovery of the artemisinin and its treatment of malaria is considered to be the most significant discovery of tropical medicine of the 20th century, which has considerably improved the health of people in tropical developing countries of south Asia, Africa and South America.

 

This is our particular tribute to this scientist who developed their research, worthy of a Nobel Prize in Medicine, in an era of secrecy and conspiracy at the highest levels.

 Your Youyou, Nobel Prize in Medicine 2015, Bengt Nyman, CC BY-SA 4.0 

In terms of  the antimalarial action, artemisinin directs its effects on the parasites Plasmodium falciparum in its erythrocyte phase of the infection, at which time the parasite is found invading the inside red blood cells and it is still not able to reproduce. 

In blood, the artemisinin is hydrolyzed completely to DIHYDROARTEMISININ, which has a half-life of approximately one hour in plasma. A dosage of one or two times a day results in a reduction of four orders of magnitude of the biomass of the asexual parasite by 48h of treatment.

The short life of the artemisinin derivatives reduces to a minimum the time period available for the selection of resistant strains. Hence the importance of the treatments containing derivatives of artemisinin-based combination therapies. It is for this reason that the Artemisin Combination Therapies (ACTs) are today, the standard treatment at the global level against malaria.

 

Image credits: Penwin, Christoph Burgstedt / shutterstock.com

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