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Scientists Hijacked Tobacco Plants to Make Malaria Drugs

A promising new advance could make the world’s best anti-malarial drug more widely available

Tombac, a form of tobacco, grows on a farm in Darfur. The plant could one day be used to create cheaper, better anti-malarial drugs. (UNAMID - Flickr/Creative Commons)
smithsonian.com

Malaria is one of the modern world’s most pressing public health challenges—a disease made even trickier by how difficult it has proven to come up with and mass produce new treatments. But now, a scientific breakthrough could change this. Researchers have learned how to hack tobacco plants to manufacture the most effective anti-malarial treatment in quantities that could one day make the drug more widely available.

In new research published in the journal Molecular Plant, an international team reveals how they genetically engineered tobacco plants to produce a compound called artemisinin. The compound is found in sweet wormwood, or Artemisia, an herb that is found in China, Vietnam and parts of east Africa. The plant has long been used in traditional Chinese medicine to treat fevers, and in the 1970s the compound was extracted by Tu Youyou. The Chinese pharmaceutical researcher was part of a research group commissioned by Chairman Mao to find malaria treatments for North Vietnamese soldiers. She wondered if traditional remedies could hold promise, and eventually won a Nobel Prize in Medicine for her work.

Since Youyou’s discovery, artemisinin has become an anti-malarial superstar. Drugs containing the compound are the most popular treatment for malaria and are recommended by the World Health Organization as the best available treatment. But there’s a problem: Though the compound eliminates malaria from a patient’s bloodstream completely within just two days, it takes a long time to cultivate and is hard to grow in some of the places where malaria is most common. Like other antimalarial drugs like quinine, which has not yet been synthesized commercially, it’s hard to create in quantities large enough to sell in the countries that need artemisinin most, until now.

By inserting the genes of sweet wormwood into the cell nuclei of tobacco, which grows easily in the places wormwood doesn’t, the team was able to hijack the plant’s photosynthetic processes to create artemisinin. Not only does their method produce the compound in a plant that’s hardy enough to withstand the climate of places like India and Africa, where malaria is most common, but it also produces the compound more quickly than wormwood.

When the team fed artemisinin extracted from tobacco to mice infected with malaria, it was more effective than the compound grown within wormwood. That suggests that it’s possible to ditch the process of growing wormwood and extracting the compound commercially altogether, the team writes.

There’s one challenge, though: Tobacco has a reputation when it comes to public health, and it could be hard to get people to eat or ingest a drug that comes from tobacco plants. But Henry Daniell, a biochemist at the University of Pennsylvania who co-authored the study, potentially has a solution: Why not use lettuce, which grows quickly and inexpensively to do the same thing they’ve pulled off with tobacco?

“Obviously, the next step is to take this to humans,” he tells Smithsonian.com. However, he says, “the FDA would not approve anything made in tobacco.” Daniell and collaborators have proven that it’s possible to grow drugs in lettuce—a system that’s cheap easy to scale and that has now been tested in both hemophilia drugs and the polio vaccine.

Daniell hopes to show that it’s possible for anti-malarials, too, and piggyback off of eventual fast-track approval for the lettuce-produced polio vaccine. If the team is able to prove that their method works with already-approved drugs, he notes, “We don't have to go through the extensive approval process.” If it works, he says, artemisinin grown by plants could be on the market within the next few years.

Whether through lettuce or tobacco leaves, it could soon become a lot cheaper to produce a drug that could reduce the estimated 438,000 people per year who die of malaria. Producing malaria medications will likely remain complicated, especially given parasites’ uncanny ability to mutate and become resistant to anti-malarial drugs. But to solve a scourge that takes a toll on over 200 million people each year, humanity will have to rely on every tool in the anti-malarial arsenal—and if the research involves hijacking a plant known for hurting more than it helps, so much the better. 

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