Berry Bad News for Cancer Cells
By Judy McBride
December 28, 2001

Fruits and vegetables contain a wide array of compounds--or phytonutrients--reported to have anti-cancer activity in cell cultures. And berries are reportedly rich in antioxidant phytonutrients. Now, Agricultural Research Service and Clemson University scientists are probing an assortment of berries, as well as muscadine grapes--a native of the Southeast--for their ability to inhibit the growth of cell lines originally cultured from breast and cervical tumors. Preliminary findings are very promising. But their ultimate efficacy in people will have to be established through clinical trials.

Various extracts from muscadine grapes, raspberries and strawberries cut the growth of breast cancer cell lines and cervical cancer cell lines by more than half, according to David E. Wedge, a plant pathologist at ARS' Natural Products Utilization Research Unit in Oxford, Miss. Wedge and ARS chemist Kumudini Meepagala prepare extracts of the berries using various solvents and different parts of the fruit, such as juice, skin and seeds. They send the extracts to Lyndon L. Larcom, professor of microbiology and molecular medicine at Clemson University in South Carolina, for assays on the cancer cell lines. After skin cancer, breast cancer is the most frequently diagnosed cancer in U.S. women and is second only to lung cancer in cancer-related deaths.

Larcom found extracts from blueberries and blackberries ineffective against the two cervical cancer cell lines being tested. But they suppressed breast cancer cell growth, with each fruit suppressing a different cell line. Larcom uses two breast cancer cell lines in these assays because their estrogen requirements are different. Specific muscadine grape extracts suppressed a third breast cancer cell line much more than they suppressed a line of healthy cells from the same donor. That means it's more selective for cancer cells. Cancer develops in stages, according to Larcom. First, a normal cell undergoes mutations. Then, the mutated cells must be stimulated to keep dividing as they get cut off from the blood supply. Finally, more mutations enable cells from a localized tumor to invade other tissues. The findings reported here deal with suppression of the second stage. The researchers are also assaying the berry and grape extracts for their ability to prevent mutations.

ARS is the U.S. Department of Agriculture's chief scientific research agency.