Fruit and veg pigments may provide bowel cancer protection
Anthocyanins - the compounds that give many fruits and vegetables their distinctive red, purple or blue colouring - can slow the growth of bowel cancer cells in the laboratory, US researchers at Ohio State University have found.
Furthermore, they discovered that slight alterations to the structure of individual molecules, such as adding an extra sugar or acid molecule, can increase the compounds' potency.
Monica Giusti, lead study author and assistant professor of food science at the university, said researchers are beginning to discover which of the various fruit and vegetables' many compounds provide the best health benefits.
Presenting the findings at the national meeting of the American Chemical Society in Boston, Dr Giusti revealed that the team had taken anthocyanins from a range of deep-coloured fruits and vegetables - including grapes, radishes, purple corn and elderberries - in order to test their effect on laboratory-grown human bowel cancer cells.
They found that the amount of extract required to halve the growth of cancer cells differs depending on the plant involved, with extracts from purple corn proving particularly potent and actually destroying around a fifth of cancer cells, while leaving healthy cells untouched.
Dr Giusti said that anthocyanins may therefore help to protect against certain cancers of the digestive (gastrointestinal) tract.
"Very little anthocyanin is absorbed by the bloodstream, but a large proportion travels through the gastrointestinal tract, where those tissues absorb the compound," she explained.
However, she noted: "While we know that the concentration of anthocyanins in the GI tract is ultimately affected by their chemical structures, we're just beginning to scratch the surface of understanding how the body absorbs and uses these different structures."
Commenting on the study, Henry Scowcroft, senior information officer at Cancer Research UK, said: "Although at an early stage, this research helps us understand exactly how the substances in fruit and veg protect us from bowel cancer.
"Isolating these substances - and tweaking them so that they're even more potent - could allow scientists to develop new drugs to treat the disease.
"In the future, it could lead to the development of drugs that help prevent bowel cancer in people at high risk," he added.