SEATTLE--From the birthplace of the microbrew come new clues that beer may contain something far more healthful than just a big dose of carbohydrates. Researchers reported here last week at the Society of Toxicology's annual meeting that several compounds in hops--the dried flowers that give beer its bitter taste--slow the growth of cancer cells in test tubes and rev up a cancer-fighting enzyme.
The group, led by toxicologists Donald Buhler and Cristobal Miranda of Oregon State University in Corvallis, isolated nine compounds called flavonoids from hops. Using standard tests for screening compounds for anticancer activity, they found that some of the flavonoids slowed the growth of human breast and ovarian cancer cells by 50% without side effects on healthy cells. And two compounds caused mouse liver cells to increase up to fourfold their production of an enzyme called quinone reductase that detoxifies carcinogens. Several of the chemicals also inhibited cytochrome P450, an enzyme that converts cancer-causing compounds like aflatoxin into their carcinogenic metabolites.
Buhler cautions that the compounds "may turn out not to be active at all" in animals. But there's reason to believe they will be: The hops' flavonoids are very similar in structure to many other suspected cancer-preventing chemicals in plants, such as genistein, a substance in soy products that may protect women in Asia against breast cancer. The hops compounds "are potent natural inducers [of quinone reductase] at fairly low doses," says University of Colorado toxicologist David Ross, who also studies the enzyme. "It's interesting."
The group now plans to move on to animal studies, but meanwhile, Oregon State has applied for patents on the compounds. Buhler says you might have to quaff quite a few bitter beers to get any anticancer benefits. But, he says, it may be possible to supply people with the flavonoids in a capsule form available, for example, in a health food store.