A natural substance which fights the fungus that harms foods such as grapes, mulberries, peanuts and beansprouts may help prevent cancer, according to a study published in the British Journal of Cancer this week.
Researchers have found that the human body will convert the product, resveratrol, into a known anti-cancer agent that can selectively target and destroy cancer cells.
Previous studies have pointed to resveratrol's cancer-fighting action, but this is the first time that scientists have gained an insight into the the way the chemical's anti-cancer properties work.
Professor Gerry Potter, who led the study, said: "Learning from nature in this way will help in our work to design drugs which are selectively activated in a tumour and can form the basis of anti cancer-treatments."
He explained that resveratrol is a defensive molecule against fungus in grapes and other crops, and is found at higher levels in those which have not been treated with man-made fungicides.
The researchers from the School of Pharmacy at Leicester's De Montfort University found that resveratrol is processed by an enzyme called CYP1B1, which is found on a variety of different types of tumours. This enzyme converts resveratrol into a toxic product called piceatannol.
Previous research by Potter's team has shown that this process is restricted to the tumour itself, limiting the toxicity to the cancer cells and serving to selectively destroy them.
The enzyme CYP1B1 has until recently been considered a cause of cancer because it is only found in tumours and not in healthy tissue.
However, far from causing cancer, scientists now think the enzyme is there to fight it and the De Montfort team is continuing research into ways which could help its function.
Professor Potter said: "The belief that CYP1B1 is a cause of cancer is like blaming police for a crime just because they are on the scene. We suspected that resveratrol might be beneficial for health and have cancer- preventative properties. This research shows just how it could prevent tumours developing by producing these anti-cancer molecules within the cancer cells themselves."
Professor Gordon McVie, joint director general for Cancer Research UK, said about the research: "Cancer Research UK has a long-standing interest in research into the use of natural products against cancer. The discovery that this molecule is converted into an anti-cancer agent within a tumour has important implications for research into prevention and treatment."
Sir Paul Nurse, joint director general of Cancer Research UK, added: "Specifically targeting cancer cells in order to destroy them is an important area of investigation which could ultimately lead to more effective drugs with fewer side effects."