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PORTLAND - A group of studies has shown that the compound chlorophyllin has great promise as a way to reduce risk of certain cancers, experts said today at a national conference on Diet and Optimum Health, sponsored by the Linus Pauling Institute at Oregon State University.

George Bailey, an OSU professor of environmental and molecular toxicology, said that anti-cancer studies done several years ago found that chlorophyllin can block liver cancer in rainbow trout, and ongoing work is outlining the molecular mechanisms and dose response of this compound with rats, mice and human volunteers.

"Chlorophyllin has the unique ability to stick tightly to certain classes of carcinogens," Bailey said. "In the stomach, it can greatly reduce the amount of this kind of carcinogen that gets taken up by the body."

Liver cancer is one of the leading causes of cancer death worldwide, Bailey said, and these findings may be of special importance in the developing world, including parts of Africa, Southeast Asia and China. In Southeast Asia, liver cancer is the third leading cause of cancer death, caused partly by a prevalence of chronic hepatitis in those areas and large amounts of aflatoxin in the diet.

"Aflatoxin is the most potent of the 50 or so compounds known to cause human cancer world-wide," Bailey said. "Aflatoxin is found in corn, peanuts and rice that have been stored in damp, moist, and high temperature areas. When the grains have been stored in these conditions, a mold begins to grow and the chemical forms."

Within the United States, the Food and Drug Administration and the U.S. Department of Agriculture screen peanuts, rice and other grains to ensure that they are aflatoxin-free. But in the Qidong province in China, one in 10 adults die of liver cancer due to life-long high aflatoxin exposure and hepatitis infection.

Bailey and colleagues from John Hopkins University have already conducted the first clinical trial of chlorophyllin on humans, a three-month project in this rural region of China. Their biomarker study showed that chlorophyllin supplements provided a 55 percent reduction in liver DNA damage from aflatoxin exposure in the diet, which they believe in the long term would translate into a similar reduction in liver cancer risk.

Although chlorophyllin has no demonstrated human toxicity, studies using rats found that chlorophyllin increased the risk of colon cancer at the same time it successfully suppressed liver cancer. Ongoing work by another OSU researcher, Rod Dashwood, is seeking to understand the basis of the increase in colon tumors and its significance for human cancer.

"Cancer is not a simple process and it's important to understand both the risks and the benefits of any new approach," Bailey said.

Bailey is working to discover in greater detail how chlorophyllin works to reduce cancer, and whether natural chlorophyll will have the same effect against other carcinogens, such as aflatoxin and components of tobacco smoke.

Definitive results on the research should be available within five years, Bailey said.