January 28, 2012
Grape Seed Extract Targets and Kills Cancer Cells and Leaves Healthy Cells Unharmed
A study published this week in the journal Carcinogenesis shows that grape seed extract (GSE) kills squamous cell carcinoma cells, while leaving healthy cells unharmed.
Grape seed extracts are industrial derivatives from whole grape seeds that have a great concentration of vitamin E, flavonoids, linoleic acid and polyphenols.
Human case reports and results from laboratory and animal studies provide preliminary evidence that grape seed extract may prevent heart diseases such as high blood pressure and high cholesterol. By limiting lipid oxdation, phenolics in grape seeds may reduce risk of heart disease, such as by inhibiting platelet aggregation and reducing inflammation.
It is estimated that 40 percent of American adults, or 50 million people, have metabolic syndrome. In a first human clinical trial, UC Davis cardiovascular researchers assessed the effect of grape seed extract on people with metabolic syndrome, a combination of risk factors that increase the risk for heart disease, including high blood pressure, excess abdominal body weight, high blood cholesterol fats and high blood sugar. They found that taking 300 milligrams of grape seed extract also had reduced serum oxidized LDL cholesterol levels.
Nearly 12,000 people will die of head and neck cancer in the United States this year and worldwide cases will exceed half a million.
"It's a rather dramatic effect," says Rajesh Agarwal, PhD, investigator at the University of Colorado Cancer Center and professor at the Skaggs School of Pharmaceutical Sciences.
It depends in large part, says Agarwal, on a healthy cell's ability to wait out damage.
"Cancer cells are fast-growing cells," Agarwal says. "Not only that, but they are necessarily fast growing. When conditions exist in which they can't grow, they die."
Grape seed extract creates these conditions that are unfavorable to growth. Specifically, the paper shows that grape seed extract both damages cancer cells' DNA (via increased reactive oxygen species) and stops the pathways that allow repair (as seen by decreased levels of the DNA repair molecules Brca1 and Rad51 and DNA repair foci).
"Yet we saw absolutely no toxicity to the mice, themselves," Agarwal says.
Again, the grape seed extract killed the cancer cells but not the healthy cells.
"I think the whole point is that cancer cells have a lot of defective pathways and they are very vulnerable if you target those pathways. The same is not true of healthy cells," Agarwal says.
The Agarwal Lab hopes to move in the direction of clinical trials of grape seed extract.