Vol. 23, Issue 1: Fall 2015

2015 Nobel Prize in Medicine: Artemisinin

Shannon Pai

As a result of institutionalized bias against herbal remedies in the 20th century, alternative medicines are not as widely accepted as western medicines in the United States. In fact, after the passage of the Dietary Supplement Health and Education Act in 1994, herbal medicines became officially labeled by the FDA as “herbal supplements”. However, after the 2015 Nobel Prize in Medicine was awarded to Tu Youyou for the development of artemisinin, a key antimalarial drug, herbal medicines have gained more recognition in the United States.

One reason that western medicines are often more trusted and widely used in the United States is that they undergo extensive research studies and clinical trials before they can be sold to the public. Herbal medicines have also gone through extensive studies, but in the form of trial and error. Traditional herbal medicine has been developed through hundreds of years of experimentation and passed down orally each generation. Healthcare providers in non-western societies often know the medicinal uses of different plants, their side effects or toxicity, dosage, and their interactions with other medicines. Some even store seeds in granaries to preserve certain genetic strains that are more effective treatments.

The power to dictate which drugs are legitimate and safe for public use is held by Western institutions such as the FDA, which results in marginalization of traditional treatments. Interestingly, many important and widely used pharmaceutical drugs such as Aspirin (Salix spp.), a drug for pain, headaches, and colds, and Taxol (Taxus brevifolia), an anti-cancer drug, are derived from molecules isolated from plants. These plants were introduced to Western researchers and physicians through collaboration with traditional healers and interpreters. Dr. Thomas J. Carlson, a medical doctor, ethnobotanist, and professor at UC Berkeley, believes that the western approach to medicine can be greatly complemented by working with local communities to better understand ethnomedicine.

One example that supports the efficacy of traditional plant-based medicine and a future for research into non-western medicines is the discovery of the anti-marlarial drug Artemisinin by Tou Youyuo. To those living in the developed world, malaria is no longer a health concern. However, the burden of malaria is still high in developing countries. According to the World Health Organization, an estimated 3.2 billion people are at risk for being infected with malaria. In 2013, there were 198 million cases globally that resulted in 584,000 deaths.

In the 1960s, the main treatments for malaria were chloroquine and quinine. But these treatments had many adverse side effect some of which were so severe that they decreased compliance to drug therapy, meaning that patients were more likely to stop using the drug. Over time, the development of resistant strains of malaria made these drugs became increasingly ineffective.

Due to the urgent need for anti-malarial drugs, China set up Project 523 to spur research in drugs that fight against malaria. Tu Youyou understood the medicinal properties of Chinese herbs, and screened over 2,000 Chinese herbs for an antimalarial drug. Eventually she and her colleagues discovered Artemisia annua, the plant artemisinin is derived from.

This plant was already known to have medicinal properties, and is documented in The Handbook of Prescriptions for Emergency Treatments written by Ge Hong in 340 A.D. In previous studies, extracts from Artemisia annua (Qinghao), a type of wormwood native to Asia, were shown to inhibit parasite growth by up to 68%. Follow-up studies, however, only achieved 12% to 40% inhibition. Tu reasoned that the low inhibition could be due to a low concentration of the active ingredient in the preparation and began to improve the methods of extraction.

Because conventional methods to isolate chemicals utilize high temperatures that could damage the active ingredient, Tu decided to switch from ethanol to ether extraction, which occurs at a lower temperature. The result was an extract with undamaged active molecules and hence improved antimalarial activity. The extract was then separated into an acidic toxic portion with no antimalarial activity and a neutral nontoxic extract with antimalarial activity. In October of 1971, the neutral extract (number 191) was tested on a strain of rodent malaria, Plasmodium berghei, and achieved 100% inhibition of the malarial parasite. While Tu’s team struggled to obtain high-quality crystals from the plant, two teams (Zeyuan Luo, Yunnan Institute of Drug Research and the late Zhangxing Wei, Shandong Institute of Chinese Traditional Medicine) of Project 523 used Tu’s information and methods to obtain pure artemisinin crystals that were highly active against rodent malaria parasites. These artemisinin crystals were then tested in human clinical trials and were very effective in treating and reducing the symptoms of malaria.

Even though the discovery of artemisinin took place in the late 1960s and the 1970s, Tu Youyou only recently gained widespread recognition after being awarded the Nobel prize. This drug has saved the lives of millions of people around the world and is currently being investigated for its potential use in cancer therapy.

Unfortunately, malaria has not been a major target of drug companies, which have historically focused their efforts on more profitable treatments for diseases prevalent in affluent countries. Thus, the discovery of artemisinin has been significant for populations more susceptible to malaria and with less access to healthcare, particularly because artemisinin has less severe side effects than synthetic pharmaceutical drugs. Often, people who have difficulty with the general side effects of pharmaceuticals can benefit from using herbal medicines that have been proven to be safe and effective through animal studies and clinical trials.

Artemisinin is currently available in a pill form and is most effective when used in combination with other anti-malarial drugs to reduce the likelihood of drug resistance. Its drawbacks include low bioavailability (the amount of each administered dose that reaches the circulation system) and high cost. People in developing countries could benefit from renewed interest in anti-malaria research in addition to research of possible chemical molecule derivatives of Artemisia annua that have higher bioavailability. Malaria is still an ailment that afflicts much of the Earth’s population, and those living in developed countries who have more access to modern research and technology should not neglect the health challenges facing less privileged populations.