The much-maligned green vegetable deserves more respect as lab tests show extracts of sulforaphane reduced tumours in mice.
Broccoli could soon protect people from cancer of the mouth, throat, neck and head in a new treatment known as “green chemoprevention.” Cruciferous vegetables such as broccoli, cabbage and garden cress have a high concentration of sulforaphane.
Previous studies, including large-scale trials in China, have shown sulforaphane helps mitigate the effects of environmental carcinogens. Now lab tests have shown extracts made from broccoli sprout protected mice against oral cancer.
American scientists now plan to carry out clinical trial on patients at high risk of a recurrence of head and neck cancer. They will be given capsules containing broccoli seed powder to determine if they can tolerate the regimen and whether it has enough of an impact on their oral lining to prevent cancer.
Associate professor Dr Julie Bauman of the University of Pittsburgh said: “People who are cured of head and neck cancer are still at very high risk for a second cancer in their mouth or throat, and, unfortunately, these second cancers are commonly fatal.
“So we’re developing a safe, natural molecule found in cruciferous vegetables to protect the oral lining where these cancers form.”
The study involved testing sulforaphane in the laboratory when over several months mice predisposed to oral cancer were given the extract and found that it significantly reduced the incidence and number of tumours.
Professor of medicine Dr Daniel Johnson at Pitt’s School of Medicine said: “The clear benefit of sulforaphane in preventing oral cancer in mice raises hope that this well-tolerated compound also may act to prevent oral cancer in humans who face chronic exposure to environmental pollutants and carcinogens.”
The research also involved giving 10 healthy volunteers fruit juice mixed with sulforaphane-rich broccoli sprout extract. The volunteers had no ill-effects from the extract and protective changes were detectable in the lining of their mouths, meaning it was absorbed and directed to at-risk tissue.
These findings were enough to prompt a clinical trial that will recruit 40 volunteers who have been curatively treated for head and neck cancer. Depending on the results larger clinical trials could be carried out.
Prof Bauman added: “We call this ‘green chemoprevention,’ where simple seed preparations or plant extracts are used to prevent disease.
“Green chemoprevention requires less money and fewer resources than a traditional pharmaceutical study, and could be more easily disseminated in developing countries where head and neck cancer is a significant problem.”
Note: The findings were presented at the American Association for Cancer Research Annual Meeting in Philadelphia.