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OpinionColumnistsMichael Dobie

The periwinkles of Madagascar

Threats might eradicate plants before we learn of their medicinal properties.

Catharanthus roseus, also known as the Madagascar periwinkle.

Catharanthus roseus, also known as the Madagascar periwinkle. Photo Credit: Getty Images/iStockphoto/istock

In 1952, Canadian research scientist Robert Noble received an envelope in the mail. Inside were 25 leaves of a plant called the Madagascar periwinkle.

Noble’s brother, a physician, sent the packet because one of his patients in Jamaica was using tea brewed from the periwinkle to treat diabetes. Doctors had been seeking alternatives to insulin so Noble, joined later by organic chemist Charles Beer, tried to produce a periwinkle extract. But it had little effect on the blood sugar of the laboratory rats into which it was injected. And the rats all developed infections and died.

That’s when their odyssey of medical discovery took an unexpected turn. The lab team noticed that the rats’ white blood cells had been destroyed by the extract. Noble and Beer realized it might serve a different purpose than the one they had explored: It might be a way to attack leukemia, a cancer associated with large numbers of abnormal white blood cells.

By 1958, Noble and Beer had isolated vinblastine, a major milestone in the development of chemotherapy. It’s used to treat Hodgkin lymphoma, bladder cancer, brain cancer and others.

But the pair wasn’t finished with the Madagascar periwinkle. In 1961, they identified vincristine, another effective chemotherapy agent. Both drugs are on the World Health Organization’s List of Essential Medicines, basically a catalog of safe and effective medicines any health system needs.

The Madagascar periwinkle, which has a lovely flower of various shades, is grown in lots of places now. But it’s under threat in its native Madagascar, because of deforestation.

That leads to a question with troubling implications: What if the Madagascar periwinkle had disappeared before Noble and Beer discovered its medical prowess?

It’s a question worth pondering, especially in the wake of the UN report released last week that found that up to 1 million plant and animal species are at risk for extinction. For many, the end could come in a few decades.

It was a difficult report to wrap one’s mind around. It’s easy to lament the potential loss of iconic animals we know are under siege — elephants, tigers, rhinos, great apes, marine turtles and the like. We understand the damage their disappearance would do to ecosystems and food chains, not to mention what that would say about our responsibility as stewards of this planet.

But many among us find it hard to muster outrage about the continued existence of plants and lesser-known animals, especially from remote places, that don’t seem to have any impact on our lives.

But they do, as countless patients who have benefited from chemotherapy could confirm. That’s the lens through which we should see the UN’s report.

About 70 percent of cancer drugs are inspired by nature, according to the UN. A similar portion of all new drugs developed in the United States come from natural sources.

Serendipity plays a role in many discoveries, as Noble and Beer showed. But serendipity only happens when there is opportunity, and that no longer exists when the plant is gone.

The anti-malaria medication quinine comes from the bark of the South American cinchona tree, isolated in 1820. Pilocarpine, derived from a shrubby tree in the Amazon in 1874, treats increased pressure inside the eye and dry mouth. Paclitaxel, one of the world’s most effective chemotherapies — you know it as Taxol — wasn’t discovered until 1971, when it was isolated from the Pacific yew tree. Turns out it’s in the bark of every species of yew tree, several of which are now endangered.

Destroying forests and other natural habitats with our machines, or losing them to warming temperatures, is a big problem. Reacting to that with a cavalier shrug is malpractice.

Michael Dobie is a member of Newsday’s editorial board.

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