The University of Arizona Alumnus / Summer 2008
Are Turmeric and Ginger The New Wonder Drugs?
by Carolyn Niethammerphotos by Jacob Chinn
Grandmothers have long prescribed chicken soup when you are achy with the flu or swollen sinuses. But if your grandmother were in India, she'd suggest a spoonful of powdered turmeric in warm milk. A Chinese grandmother would give you ginger tea with lemon.
Those plant-based remedies have worked for thousands of years for many ailments and seem to have no dangerous side effects at low levels. At The University of Arizona, researchers in several disciplines are joining scientists all over the world in investigating whether these ancient treatments work as well as modern drugs — or even better. Dosage is a more complex question. So are the physiological mechanisms that make these plants work. Finding the answers takes years, generous funding, and the creative intellect of many researchers.
Here's what's known, according to David Gang, a professor in the Department of Plant Sciences and the Department of Biochemistry and Molecular Biophysics and a member of the Bio5 Institute. Both turmeric and ginger have powerful anti-inflammatory properties. This makes them widely effective because many common illnesses are caused or worsened by chronic inflammation.
"The most common inflammatory disease is arthritis," Gang explains, "but inflammation also figures in cancer because cancer tumor cells turn on inflammation in local cells. This leads to more blood going to the cells, which helps cancer grow. Turmeric also is of interest in Alzheimer's disease because of the inflammation around the neurons in the brain. Unlike some other compounds, the active components in turmeric extracts will pass the blood-brain barrier."
Gang himself is a convert to the natural medicines he studies. Several years ago, he suffered from stomach and intestinal problems. After doctors failed to find a cause or cure, he began taking ginger. He healed himself, he says, and still makes it a regular part of his diet.
With a broad interest in the biochemistry of aromatic plants, Gang began his turmeric research while associated with the now-closed Arizona Center for Phytomedicine Research, which was funded by the National Institutes of Health to look at unregulated dietary supplements. At the time, Vioxx had just been taken off the market, and there was a push to find something that would ease the pain of arthritis without the difficult side effects.
In both turmeric and ginger, the bioactive compounds are found in the rhizome, or underground stem. In his lab in the Bio5 building, Gang picks through a box of dusty-brown, knobby turmeric rhizomes, about the size of a man's thumb. He breaks one open to reveal its bright gold flesh. Turmeric is the main ingredient in curry powder and is responsible for its gold color as well as for the bright yellow of some mustards.
In early March, the rhizones are dormant, but Gang plants them in early spring in his greenhouse on the top floor of a university parking garage. Here he can simulate the tropical environment these plants need. By late May, they are sprouting deep-green leaves, well on their way to their full tropical lushness.
Curcumin, the source of the golden color, is the most active compound in turmeric. Other related compounds, called curcuminoids, also are beneficial. Ginger contains active compounds called ginerols — the same class of chemicals as curcumin — with small amounts of curcuminoids and other related compounds.
"We don't know much about metabolism in plants," Gang says, nor the mechanisms involved in the formation of almost all natural products from plants.
To try to learn how these natural-medicine factories work, the associates in the Gang lab are using the latest systems-biology tools. They investigate how the enzymes and genes in turmeric and ginger synthesize these active compounds by using a multidisciplinary approach involving chemistry, biochemistry, molecular biology, plant physiology, whole organism biology, and ecology.
Other university scientists continue to research other aspects of turmeric and ginger. Among them is endocrinologist Janet L. Funk. In 2006, she was the lead author on a paper that described how the curcumins in turmeric inhibited the onset of rheumatoid arthritis in rodents.
To Funk, it is understandable that turmeric and ginger would be effective biopharmaceuticals. "Eighty percent of the world's population relies on traditional medicine from plants," she explains.
Although a great many modern drugs are based on plant analogs, the modern versions usually isolate a single effective compound. But Funk sees the importance of looking at the whole plant.
"For complicated diseases, people need a cocktail of drugs," she says. Botanicals are a natural cocktail. The curcuminoids in turmeric look incredibly promising for rheumatoid arthritis.
She pauses. "But we haven't done the safety profile yet, particularly in patients who are already taking lots of other drugs." As the next step, she has submitted a grant to fund drug trials in humans to test safety.
Although commercial preparations of turmeric are available in health-food stores marketed as a dietary supplement, in earlier research none of them tested out to contain the level of active ingredients they claimed to have. To do credible research, researchers must have a standardized compound. So, other UA researchers worked out a way to prepare their own turmeric extracts of the major curcuminoids. Because the process was so successful, they patented it.
Taking that research to the next step, Aniko Solyom, an analytical chemist and member of the original UA turmeric study group, is working on getting an even better extract.
"(In the original research) even if we did the extraction exactly the same way, the bioactivity of the compound varied quite a bit," Solyom says. "So we have to develop a method that is always reliable." She is now setting up a lab at the Arizona Center for Innovation, the university's high-tech business incubator, and applying for grants to further the research.
"There are more than 30 varieties of turmeric," she explains, "and the chemical composition differs a great deal."
Meanwhile, as Funk seeks funds to test curcumin in humans, Solyom tries to make a better product, and the Gang lab attempts to figure out how and why the compounds work.
Once Gang and his associates determine how turmeric and ginger make their effective compounds, Gang plans to use modern plant-breeding techniques to introduce them into other common food plants, such as potatoes. If the compounds are in more foods that Americans actually eat, it will be easier for them to benefit from their natural anti-inflammatory properties.
"People in our culture don't each much curry," he says, "and we surely don't eat enough mustard."
Gang just buys turmeric in the spice aisle at the grocery store and sprinkles about a half teaspoon a day onto whatever he is having for dinner. So while he and other researchers continue to pursue their scientific investigations over the next few years, it probably wouldn't hurt to follow his dinner table example and put a slice of fresh ginger in your tea or sprinkle some turmeric on your chicken soup.
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