OSU studies cottonseed oil as possible anti-cancer agent

COLUMBUS, Ohio --A veteran researcher in The Ohio State University Comprehensive Cancer Center (OSUCCC) is investigating a key ingredient in cottonseed oil as a possible anti-cancer agent.

Dr. Young C. Lin, a professor of reproductive endocrinology at The Ohio State University College of Veterinary Medicine and a member of the OSUCCC's Hormones and Cancer Program, recently received a three-year, $450,000 dollar grant from the Department of Defense Breast Cancer Research Program to study the effects of a diet rich in cottonseed oil on mammary tumors in rats. If the findings are consistent with earlier in vitro experiments, they could point to cottonseed oil as a dietary supplement for women at high risk of developing estrogen-related breast cancer.

Dr. Lin explained that cottonseed oil contains gossypol, a naturally occurring phenolic compound which has been shown to be a powerful inhibitor of tumor growth and metastasis in some estrogen-induced cancers. He points out that cottonseed oil, which contains gossypol in very small quantities, is present in many foods, including salad dressing, shortening, margarine, some canned and snack foods, and in abundant quantities in dietary replacements like Procter & Gamble's Olestra.

Gossypol is actually a yellowish pigment, and because too much of it is toxic to humans, the Food and Drug Administration requires most of it be eliminated from food production. In 1996, an estimated 12,000 metric tons of gossypol were processed as waste. Ironically, however, a little bit of gossypol is apparently a very good thing.

"Interestingly, we have demonstrated through our preliminary results that food-grade gossypol-containing cottonseed oil possesses extremely potent anti-proliferative activity against cancer cells in vitro that is far greater than that of chemically prepared gossypol, "says Dr. Lin, noting that only a tiny fraction of the 450 parts per million allowed by the FDA is enough to be efficacious.

"These in vitro findings," he continued, "indicate that consumption of foods containing cottonseed oil may deliver quantities of gossypol sufficient to achieve desired biological effects but without toxicity." To test his hypothesis, Dr Lin is examining the effects of a diet formulated with cottonseed oil on rats with estrogen-related mammary tumors.

Dr. Lin says his laboratory, in conjunction with researchers from the Southern Regional Research Center of the United States Department of Agriculture in New Orleans, is continuously working to identify and isolate the most powerful form of gossypol.

So far, he says, they believe a particular form of gossypol, identified as the enantiomer (-)GP, is the most potent, adding they will be presenting the findings at the meeting of the American Association for Cancer Research in New Orleans in March.

Meanwhile, those thousands of tons of wasted gossypol produced every year are beginning to look better and better. "Due to the abundance of gossypol as waste, we believe that investment in basic research of its anticancer properties could lead to the development of a reasonably inexpensive therapeutic or preventive agent for human breast cancer," Lin says. This should appeal to both to cotton growers, who would find new value in their product, and to women at high risk of developing breast cancer, who would have yet another preventive agent in their arsenal against cancer.