The cancer-fighting properties of broccoli, a member of the crucifer family of vegetables, are not new and previous studies have related these benefits to the high levels of active plant chemicals called glucosinolates. These are metabolized by the body into isothiocynates, and evidence suggests these are powerful anti-carcinogens. The main isothiocynate from broccoli is sulphoraphane.
Broccoli has now become the most popular cruciferous vegetable in the US, though its cultivation is relatively new in North America having been introduced to the continent around 60 years ago from Italy.
Dr. Janet Cross, an assistant professor of pathology at the University of Virginia School of Medicine, told NutraIngredients-USA.com that the anti-cancer benefits of isothiocyanates are well-established but no-one knows what these compounds do.
"Everyone knows broccoli is good for you and that it contains compounds known to lessen the occurrence of some types of cancer. We want to know how these compounds work and what their specific targets may be," said Dr. Janet Cross, an assistant professor of pathology at the University of Virginia School of Medicine.
The new five-year project, funded by a $1.3m grant from the National Cancer Institute (NCI), will build on research by Dr. Cross and her colleague, Dr. Dennis Templeton, that reported that nutrients in broccoli unexpectedly bond with a specific enzyme in cells (MIS), previously linked to inflammatory disease processes. Dr. Cross extended this science by finding that mice that did not have the gene for this enzyme developed far fewer cancers when given carcinogens. This research has yet to be published in a peer-review journal.
"It seemed provocative in that if the cells were missing these genes they seem less susceptible to cancer," said Dr. Cross. "This may represent the means by which these nutrients impact on the cancer promoting activities of carcinogens in the environment."
The view of Drs. Cross and Templeton has been from a molecular biology point of view, but understanding the mechanism behind the anti-cancer effects may also have implications for both nutra- and pharma-ceuticals.
While some suggestion is made that the compounds from broccoli that have a reported anti-cancer activity could be used as cancer preventions, and come in the form of a pill or beverage, Dr. Cross cautioned that the Virginia researchers do not have a "great feel" whether the doses needed to attain a physiological effect could be "attainable with a food product."
Some broccoli-extracts are currently available on the market, such as Cyvex's Nutrition's BroccoPlus, combines six per cent glucosinolates with sulforaphane, delivering high doses of these compounds in powder form, and B&D Nutritional Ingredients' sgs-100, a broccoli seed extract from a plant strain that is reported to be unusually high in sulforaphane glucisinolate (SGS).
For Dr. Cross, there is also a personal pull to developing and potentially extracting these anti-cancer compounds: "The real irony is that I can't stand broccoli," she said.