Published on 02/18/98

Odd Beans May Be 'Unopened Medicine Chest'

Beans are a great source of protein in diets. But some lesser- known cousins of black-eyed peas and kidney beans may have something far better. They may hold the key to fighting cancer, leukemia and Parkinson's disease.

Working at the University of Georgia Experiment Station in Griffin, Brad Morris maintains more than 190 legume species. Most originated in tropical countries.

Morris is a special legume curator with the U.S. Department of Agriculture. For the past year, he has been on a mission to unlock potential medicinal qualities hidden inside 13 of the legume species.

"Who's ever heard of velvet bean, jack bean, winged bean, fish poison bean or crotalaria?" Morris said. "These beans all contain useful, potentially therapeutic, phytochemicals that could someday be of great benefit to humankind."

The "phyto" means, simply, "plant." These bean plants contain chemicals that, for most, are inedible. Some contain alkaloids that are toxic to people and animals.

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"For example, fish poison bean contains rotenone, which South American natives use to stun fish so they can be scooped from rivers," Morris said. "But rotenone is also known to fight tumors in humans. In small quantities, alkaloids can have therapeutic value and could help fight cancer and ulcers."

Winged bean and crotalaria also contain phytochemicals known to fight tumors. Crotalaria contains monocrotaline, too, which is known to fight tumors and leukemia. And jack bean contains canavanine, which combats flu, bacteria, fungi and viruses.

To unlock the health benefits of these legumes, Morris is attracting interest from biochemists and ethnobotanists. "My job as an agronomist and curator is to let researchers know the potential uses of these legumes," he said. "I'm in search of collaborators."

Over the past year, Morris' search has had some success. A California scientist requested winged beans for research on edible vaccines. Winged beans contain high levels of lectins. Medical researchers use lectins as diagnostic tools because they bind to certain blood cells and specialized transport cells.

The winged bean lectin, when fed to mice, reportedly stimulated their immune systems to produce antibodies that recognize the lectin. The same response is noted from a vaccine.

"Edible vaccines are a new area interesting to both scientists and the public," Morris said. "I'm sure everyone would much rather ingest a vaccine instead of getting a shot."

A group of Italian researchers also contacted Morris. The group is studying velvet bean as a source of dopa, which the human brain converts into the neurotransmitter dopamine. Parkinson's disease occurs when brain cells that produce dopamine are destroyed.

Morris calls the legume collection his "unopened medicine chest."

"I'm trying to gain as much interest in the scientific community as possible," he said. "I want to spread the word as far as possible and maybe reach a pharmacologist or phytochemist who is interested in this area of research."

Americans don't have to wait, though, to reap the benefits of legumes.

"Beans and other legumes are a delicious and inexpensive way to add nutritious, healthy foods to our diets," said Connie Crawley, a nutrition and health specialist with the UGA Extension Service.

"Research indicates a cup of beans eaten daily can lower cholesterol as much as 12 percent, cut the risk of colon cancer, slow the rise of blood glucose after meals and increase a sense of fullness in those trying to control their weight," she said.

Crawley said soybeans in particular have received a lot of research attention of late. "No one is sure how much soy is needed to see the beneficial effects," she said. "It may be more than what can be eaten in a normal Western diet."

She said the main problem is finding soybean products the average American will eat. "Tofu and soynuts are probably the most widely accepted," she said.

Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.