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Fall Color In-Depth: Maple Trees Offer New Answers to Diabetes, Alzheimer’s

Are answers to diseases hidden in the leaves and bark of trees such as maples? Researchers are finding out. (Photograph: University of Rhode Island) In the 1992 film Medicine Man, biochemist Robert Campbell, played by actor Sean Connery, searches for new drugs in the Amazon’s vast rainforests. There Campbell finds a cure for cancer not in...

Are answers to diseases hidden in the leaves and bark of trees such as maples? Researchers are finding out. (Photograph: University of Rhode Island)

In the 1992 film Medicine Man, biochemist Robert Campbell, played by actor Sean Connery, searches for new drugs in the Amazon’s vast rainforests. There Campbell finds a cure for cancer not in the rainforest’s rare flowers – which don’t have “juju,” or the power to heal – but in an indigenous ant species.

All is looking up, until a logging company builds a road straight to Campbell’s research station. The biochemist demands that the construction stop. A fight breaks out, a bulldozer goes up in smoke, and the research station is destroyed. Along with it, acres of rainforest burn to the ground, taking the cure-containing ants with them.

Campbell perseveres, however. He remains in the Amazon, convinced he’ll locate more ants and stop cancer in its tracks.

Two decades after Medicine Man’s appearance, such seemingly fanciful discoveries are becoming realities.

Maple trees may be the path to new disease treatments.
The road to new treatments for common diseases may take scientists toward maple trees. (Photograph: NPS)

Thousands of miles from the tropical rainforest and far from any movie theater, other medicine men are on the path to cures – in this case, to inflammation and metabolic syndrome, a cluster of conditions that includes high blood pressure and elevated blood sugar and cholesterol levels.

Metabolic syndrome increases the risk of heart disease, stroke and diabetes. Remedies couldn’t come too soon: the overall prevalence of metabolic syndrome in the U.S., according to the Journal of the American Medical Association, is 33 percent.

As fall arrives and the leaves of sugar maples and red maples turn flame orange and deep crimson, could maple trees offer new answers to these all-too-common diseases?

To discover the medicinal secrets of maples, I talked with biochemist Navindra Seeram of the University of Rhode Island in Kingston, Rhode Island. Seeram is conducting research on plants’ bioactive properties. Amid bubbling beakers in his lab, he offered an in-depth look at autumn’s iconic maples.

Navindra Seeram at work at the University of Rhode Island.
Scientist Navindra Seeram and a member of his team study medicinal plant extracts. (Photograph: University of Rhode Island)

What led to your research on maple trees as sources of possible disease treatments?

There’s a lot of evidence for the ethnomedicinal use of maples — native peoples prized maple bark, for example, as a “liver tonic.” Today, maple syrup is the most-consumed and commercially produced food product obtained entirely from the sap of deciduous trees. It’s mostly tapped from sugar maples and red maples in eastern North America. These maples have biochemical substances in their leaves, bark and sap that may counteract inflammation, the root of many of the diseases we’re facing.

Do all maple trees have these biochemical properties?

Yes and no. Our studies of several maple species show that there are minor variations in the biochemistry of the sap, but larger differences in the biochemistry of other parts of the trees.

Based on research in your lab, what diseases could maples cure?

I don’t like to use the word “cure” for plant-derived foods such as maple syrup because they’re usually more preventive than therapeutic. But research on non-human animals demonstrates that maple syrup reduces the inflammation associated with metabolic syndrome and other diseases.

A maple "sugarbush": a pharmacy in the wild?
Maple syrup may help with metabolic syndrome and type-2 diabetes. (Photograph: Wikimedia Commons)

How can a syrup that tastes sugary potentially counteract metabolic syndrome and diabetes?

Maple syrup won’t cure metabolic syndrome or diabetes. But its unique “cocktail” of minerals, vitamins, amino acids, organic acids and phytochemicals [plant chemicals] may work against the inflammation linked with, for example, type-2 diabetes. Among sweeteners, I believe that maple syrup is a healthier choice than refined sugar. However, like everything else, it should be consumed in moderation. My advice is to drizzle, not guzzle!

With Alzheimer’s disease on the rise in the U.S. and around the world, do maples offer any hope?

A healthy lifestyle that includes enough exercise and a proper diet may prevent or delay the onset of several chronic human diseases, including cancer, heart disease and some neurodegenerative diseases like Alzheimer’s. There are also indications of beneficial effects of maple compounds on Alzheimer’s, possibly by counteracting neuroinflammation.

Sugar maples are attractive well beyond their fall foliage.
Sugar maples are attractive for more than their beautiful fall foliage. They may contain new treatments for diseases such as Alzheimer’s. (Photograph: Wikimedia Commons/Famartin)

Do you foresee new drugs being developed from maple trees?

Yes. Certain molecules in maple syrup could be synthesized and modified into substances with drug-like properties. Extracts of maple syrup that are sugar-reduced and phytochemical-enriched, as well as extracts of other maple parts, are being developed by my group as nutraceuticals. Nutraceuticals are standardized extracts derived from foods, including plants. In the U.S., nutraceuticals are regulated by the Food and Drug Administration as dietary supplements and food additives.

If maple syrup and leaves contain potential new treatments, how can people obtain the benefits? How much would be needed to make a difference?

Before we can understand dosing, we’ll need to wait for the results of studies on maples’ effects on people.

Sugar maples range across northeastern North America.
In North America, sugar maples range from Canada south along the Appalachian Mountains and across the U.S. Upper Midwest. (Map: USGS)

Is research on maples and disease taking place in other countries? For example, Canada is known for its maple trees.

There are ongoing studies on maples and their health benefits in Canada and Japan, which, like the U.S., have extensive stands of maple trees.

What’s next in the link between maples and human health?

We’re expanding from maple sap and syrup to studies of other parts of the tree, such as using leaves in brewed teas, and bark as a spice like cinnamon. Compounds in almost every part of a maple tree show promise in fighting disease.

Should we all grow a sugarbush — a plantation of sugar maples – in our backyards?

As compared with cutting down the trees and constructing more shopping malls, yes! Who knows what formulas for health that sugarbush might someday reveal?

At URI's Medicinal Garden, visitors may peer at a range of medicinal plants.
At the University of Rhode Island’s Heber W. Youngken, Jr. Medicinal Garden, visitors see plants that help treat everything from heart disease to cancer. (Photograph: University of Rhode Island)

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Meet the Author

Author Photo Cheryl Lyn Dybas
Award-winning science journalist and ecologist Cheryl Lyn Dybas, a Fellow of the International League of Conservation Writers, brings a passion for wildlife and conservation to National Geographic, Natural History, National Wildlife, BioScience, Yankee and many other publications, and is a Field Editor at Ocean Geographic. Eye-to-eye with the wild is her favorite place to be.