Ellagic acid

Berry good and nutty anticaner agent?

A basket of fruits and nuts may be both gracious hospitality gift and a tasty cancer preventive, say scientists from the Medical College of Ohio in Toledo. A substance called ellagic acid -- found in fruits like strawberries and in Brazil nuts -- scavenges carcinogenic chemicals and prevents normal cells from becoming cancerous, says Gary D. Stoner. He and his coworkers are studying its effects on carcinogenesis caused by different chemicals.

Among the cancer-causing agents included in the study were polycyclic aromatic hydrocarbons (PAHs) found in tobacco smoke and auto exhaust, nitrosamines found in tobacco smoke and foods, and aflatoxins found in certain foods such as stored nuts. Assays using cultures of mouse and human lung tissue showed that ellagic acid reduced DNA damage caused by PAHs, for example, by 45 to 70 percent, says Stoner. He says ellagic acid, which is a member of the phenol chemical group, also inhibits the formation of PAH-induced lung cancer in mice. The researchers observed similar inhibition against aflatoxins and nitrosamines tested in the same system.

Stoner says the group is considering large epidemiologic studies in China, where people living in certain valleys have high rates of cancer that some researchers think are related to the nitrosamine-containing chemicals used to pickle food (SN: 9/5/87, p. 148). By providing ellagic acid in the diet, the scientists hope to reduce the cancer's incidence. Despite the promising results in the present study, however, Stoner emphasizes that ellagic acid can be used only as a preventive, because it has to be added to the system just before or during carcinogen exposure. But Stoner says he does not necessarily recommend that diners drink wine (grapes are another source of ellagic acid) when eating nitrosamine-laced overcooked meat, because of the possible dangers of ethanol.

Although the researchers have yet to define the exact mechanism of cancer inhibition, they suspect that the ellagic acid competes for DNA receptors that are also used by the carcinogens. Because purified ellagic acid has difficulty crossing intestinal walls, the group is tinkering with its structure to improve its absorption into the body. The substance, which apparently is bound to glucose in nature, may be more easily absorbed in its natural state, says Stoner.

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