University points out rush to harness compounds that battle cancer

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Since scientists at Oregon State University first discovered the cancer-related properties of this flavonoid compound called xanthohumol about 10 years ago others in programs around the world started to look at the value of these hops flavonoids. Researches have suggested everything from preventing prostate or colon cancer to hormone replacement therapy for women.

"Xanthohumol is one of the more significant compounds for cancer chemoprevention that we have studied," said Fred Stevens, a researcher with OSU's Linus Pauling Institute. "The published literature and research on its properties are just exploding at this point, and there's a great deal of interest."

An update about the research comes shortly after a New York doctor issued a warning that heavy drinkers of both spirits and beer have a higher risk of developing colon cancer.

Reports of that study didn't detail the hop levels of beers involved, but the OSU release noted that some beers have higher levels of xanthohumol than others. Most mainstream U.S. lagers have fairly low levels of the key compounds, but many specialty beers are hopped at higher levels.

Hop-containing herbal preparations are already being marketed for breast enlargement in women, the OSU research report said, without waiting for tests to verify their safety or efficacy. And a supposed "health" beer is being developed in Germany with higher levels of xanthohumol.

"We can't say that drinking beer will help prevent cancer," Stevens said. "Most beer has low levels of this compound, and its absorption in the body is also limited. But if ways can be developed to significantly increase the levels of xanthohumol or use it as a nutritional supplement - that might be different. It clearly has some interesting cancer chemopreventive properties, and the only way people are getting any of it right now is through beer consumption."

Xanthohumol appears to have several mechanisms of action that relate to its cancer preventive properties, scientists say. It, and other related flavonoid compounds found in hops, inhibit a family of enzymes, commonly called cytochromes P450 that can activate the cancer process. It also induces activity in a "quinone reductase" process that helps the body detoxify carcinogens. And it inhibits tumor growth at an early stage.

In recent years, it has also been shown that some prenylflavonoids found in hops are potent phytoestrogens, and could ultimately have value in prevention or treatment of post-menopausal "hot flashes" and osteoporosis - but no proper clinical trials have been done to study this.