When 18 malaria patients in the Congo failed to respond to conventional treatments and instead continued to head toward terminal status, doctors knew they had to act fast – and try something different. So instead of turning to more synthetic drugs, they turned instead to nature and found a solution that delivered remarkable results.

The patients were first treated with the regimen described by the World Health Organization (WHO): artemisinin-based combination therapy (ACT). This drug combines an extract from a plant known as Artemisia annua, with other drugs that launch a multi-pronged attack on the malaria parasite. But just as is the case with antibiotic-resistant bacteria, the malaria parasite is evolving to resist the drugs designed to kill it. In fact, according to the WHO, three of the five malarial parasites that infect humans have shown drug resistance.

As the patients continued to decline, with one five-year-old even entering into a coma, the doctors administered a drug called artesunate intravenously, which is the preferred course of action when treating severe malaria. The treatment didn't work.

Finally, doctors turned to the Artemisia annua plant itself. Also called sweet wormwood or sweet Annie, the plant is the source of the chemical artemisinin, which is used in ACT therapy. The plant has been used since ancient times in Chinese medicine to treat fevers, although this bit of knowledge was lost until 1970 when the Chinese Handbook of Prescriptions for Emergency Treatments (340 AD) was rediscovered. In 1971 it was found that extracts from the plant could fight malaria in primates.

Pamela Weathers, professor of biology and biotechnology at Worcester Polytechnic Institute began researching Artemisia annua over 25 years ago. Along with postdoctoral fellow Melissa Towler, Weathers created a pill made from nothing more than the dried and powdered leaves of the plant. When the pills were given to the 18 dying patients over the course of five days, all of them completely recovered, with no trace of the malaria parasite remaining in their blood.

"These 18 patients were dying," Weathers said. "So to see 100 percent recover, even the child who had lapsed into a coma, was just amazing. It's a small study, but the results are powerful."

Weathers had previously shown that the dried leaves of the Artemisia annua plant (DLA) could deliver 40 times more Artemisia annua to the blood than extracts of the plant alone. In a later experiment, she showed that not only could the leaves beat drug-resistant bacteria in mice, but that after passing the malaria parasite through 49 generations of mice, the parasite still showed no resistance to the plant.

While the exact mechanism through which DLA operates is unclear, Weathers says it's likely due to the intricate chemical dance that occurs between the phytochemicals in the leaves.

Weathers with the Artemisia plant(Credit: Worcester Polytechnic Institute)

Because the drug is inexpensive and relatively simply to produce, Weathers also says that it could be a source of industry for people living in the areas where malaria is a problem, such as Ghana, Kenya and Malawi where it was recently announced that the first malaria vaccines will be deployed. "This simple technology can be owned, operated, and distributed by Africans for Africans," said Weathers, who has already established a supply chain on the continent for the leaves using local producers.

Weathers also said that further research into DLA could lead to effective ways to combat other maladies.

"We have done a lot of work to understand the biochemistry of these compounds, which include a number of flavonoids and terpenes, so we can better understand the role they play in the pharmacological activity of the dried leaves," Weathers said. "The more we learn, the more excited we become about the potential for DLA to be the medication of choice for combatting malaria worldwide. Artemisia annua is known to be efficacious against a range of other diseases, including other tropical maladies and certain cancers, so in our lab we are already at work investigating the effectiveness of DLA with other diseases."

The results of the case in the Congo have been described in the journal Phytomedicine. You can hear more from Weathers in the video below.

Source: Worcester Polytechnic Institute

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