Broccoli Sprout Extracts May Prevent Recurrence of Some Oral Cancers
Broccoli, a source of folic acid.
Beverages derived from broccoli sprout extracts were found to have preclinical chemopreventive activity against oral cancer induced by carcinogens. Potent doses of extract from broccoli sprouts activate a detoxification gene and may help prevent cancer recurrence in survivors of head and neck cancer.1
This study is the first to demonstrate that the extract protects against oral cancer. This conclusion is based on human, animal, and laboratory tests conducted at the University of Pittsburgh Cancer Institute, partner with University of Pittsburgh Medical Center (UPMC) Cancer Center, Pittsburgh, Pennsylvania. The research was funded through a Specialized Program of Research Excellence grant in head and neck cancer from the National Cancer Institute.
"With head and neck cancer, we often clear patients of cancer only to see it come back with deadly consequences a few years later," said Julie Bauman, MD, MPH, co-director of the UPMC Head and Neck Cancer Center of Excellence, and lead author of the study. "Unfortunately, previous efforts to develop a preventative drug to reduce this risk have been inefficient, intolerable in patients, and expensive. That led us to 'green chemoprevention' — the cost-effective development of treatments based upon whole plants or their extracts."
Sulforaphane is a molecule that comes from metabolizing cruciferous vegetables, such as broccoli, cabbage, and garden cress. Sulforaphane promotes the detoxification of airborne pollutants in humans. Treating human head and neck cancer cells with sulforaphane increased their levels of a protein that turns on genes that detoxify carcinogens, such as those found in cigarettes.
A small preclinical trial described in this study had 10 healthy volunteers drink or swish fruit juice mixed with broccoli sprout extract for several days. The volunteers had no significant problems tolerating the extract and the lining of their mouths showed that the same protective genetic pathway activated in the laboratory cell tests was activated in their mouths, meaning that the sulforaphane was absorbed and directed to at-risk tissue.
In mice predisposed to head and neck cancer, sulforaphane treatment led to the mice developing far fewer tumors than their untreated counterparts.
The results of the mouse, human, and laboratory studies have been so successful that Bauman has started a larger clinical trial in volunteers previously cured of head and neck cancer. These participants are taking capsules containing broccoli seed powder, which is more convenient to take regularly than the extract mixed with juice.
"Head and neck cancers account for approximately 3% of all cancers in the [United States], but that burden is far greater in many developing countries," said Bauman. "A preventative drug created from whole plants or their extracts may ease the costs of production and distribution, and ultimately have a huge positive impact on mortality and quality of life in people around the world."
1. Bauman JE, Zang Y, Sen M, et al. Prevention of carcinogen-induced oral cancer by sulforaphane. Cancer Prev Res (Phila). 2016 Jun 23. doi:10.1158/1940-6207.CAPR-15-0290. [Epub ahead of print]