Grape seed extract significantly inhibited the growth of colorectal tumors in both laboratory cell cultures and in mice, U.S. researchers report. A team from the University of Colorado Health Sciences Center in Denver says mice given the extract displayed a 44 percent reduction in the size of advanced colorectal tumors.
The researchers also determined how grape seed extract works to inhibit cancer growth. It does so by increasing the availability of a protein (Cip1/p21) in tumors that “freezes” the cell cycle, causing cancer cells to self-destruct.
The findings were published Wednesday in Clinical Cancer Research.
“With these results, we are not suggesting that people run out and buy and use grape seed extract. That could be dangerous, since so little is known about doses and side effects,” Rajesh Agarwal, a professor in the department of pharmaceutical sciences, said in a prepared statement.
“The value of this preclinical study is that it shows grape seed extract can attack cancer, and how it works, but much more investigation will be needed before these chemicals can be tested as a human cancer treatment and preventive,” he said.
Agarwal and his colleagues had previously demonstrated the cancer-fighting effects of grape seed extract in other types of tumors. Grape skin and seeds are a rich source of antioxidant flavonoids called proanthocyanidins.