Salman Hyder, a professor of biomedical sciences in the College of Veterinary Medicine at the University of Missouri, and colleagues said he exposed rats with a certain type of breast cancer to apigenin -- a common compound found in parsley, celery, apples, oranges, nuts and other plant products.
The study, published in the journal Cancer Prevention Research, found rats exposed to the apigenin developed fewer tumors and experienced significant delays in tumor formation compared to rats that were not exposed to apigenin. Hyder said the finding may affect women undergoing certain hormone replacement therapies.
"Six to 10 million U.S. women receive hormone replacement therapy," Hyder said in a statement. "We know that certain synthetic hormones used in HRT accelerate breast tumor development. In our study, we exposed the rats to one of the chemicals used in the most common HRTs received in the United States -- a progestin called medroxyprogesterone acetate -- which also happens to be the same synthetic hormone that accelerates breast tumor development."
Hyder said researchers have not identified a apigenin dosage for humans yet.
"However, it appears that keeping a minimal level of apigenin in the bloodstream is important to delay the onset of breast cancer that progresses in response to progestins," Hyder said. "It's probably a good idea to eat a little parsley and some fruit every day to ensure the minimal amount, after checking with your doctor."