Washington -- From the green, yucky juice of broccoli, cabbage, collards and the like, scientists have squeezed still another chemical that seems to inhibit cancer cells.
The new substance stimulates production of enzymes that can break down carcinogens, including the female hormone estrogen, Texas A&M; University researchers reported in today's issue of the Journal of the National Cancer Institute.
Trouble is, this chemical seems to work in almost the opposite way from other broccoli-derived compounds that are thought to have anti-cancer properties.
In fact, it seems to work against those other chemicals.
Researchers from the Texas university say a compound called "indole-3-carbinol," which is found in cruciferous vegetables such broccoli and cabbage, converts in the stomach to another substance that has an even longer name but is known as "ICZ."
In turn, ICZ stimulates the production of a group of enzymes that break down estrogen. Many experts think most breast cancer results from overexposure to estrogen.
The researchers say that when they placed ICZ in a tissue culture of breast cancer cells, proliferation was inhibited.
Instead of suggesting that eating sufficient amounts of broccoli will ward off breast cancer, the experiment illustrates the vigorous drug-like properties that may be found in the natural products contained in plant cells, other researchers said.
The anti-cancer properties of chemicals found in broccoli were first reported two years ago by Johns Hopkins University scientists who said they had isolated a compound, sulfurophane, which stimulated the body to produce enzymes that can destroy cancer-causing substances.
Paradoxically, these cancer-causing substances appear to be synthesized by some of the same enzymes that cells produce in response to ICZ.