Grape Seed Extract Has Cytotoxic Effects on Human Cancer Cells

NEW ORLEANS--An extract derived from the seeds of red grapes, currently available as a dietary supplement (Activin), has been shown to reduce tumor cell growth in human breast, lung, and gastric cancer cell lines, S. S. Joshi, PhD, of the University of Nebraska Medical Center, Omaha, reported at the American Association of Cancer Research 89th annual meeting. (See Figure showing the effects in breast cancer cells.)

Grape seed proanthocyanidins are natural antioxidants that possess a broad spectrum of biological, pharmacological, and chemoprotective properties against free radicals and oxidative stress, he said.

The researchers, from the University of Nebraska Medical Center, Creighton University, and Georgetown University Medical Center, added the extract at two different concentrations (25 mg/L and 50 mg/L) to cultures of cell lines of human breast cancer, lung cancer, gastric cancer, and chronic myelogenous leukemia (CML).

After incubation for 72 hours, the maximum reduction in rate of cell growth in the breast cancer cell line was 43% with 25 mg/L of the extract and 47% with 50 mg/L. "Similar results were observed in the lung cells and gastric adenocar-cinoma cells, but not in the myelogenous leukemia cells," Dr. Joshi said.

The agent was also incubated with normal human gastric mucosal cells at the same concentrations. Not only were there no cytotoxic effects on these normal cells, but cell growth actually increased, by 9% at 25 mg/L of Activin and by 18% with 50 mg/L at 72 hours.

"We are particularly excited about Activin because it is a natural food substance that appears to be toxic against certain cancer cells, while actually protecting and improving the health of normal cells," Dr. Joshi said.

Dr. Debasis Bagchi, the Creighton University scientist who led the research team, said that the findings "indicate that there may be an important role for nutritional ingredients in cancer therapies as well as cancer prevention."