The pigment that makes tomatoes red, lycopene, may help in the fight against destroying cancers of the mouth.

 A team led by Betty Schwartz, a biochemist at the Hebrew University of Jerusalem, was exploring the anticancer properties of a range of substances that occur naturally in food. The researchers were seeing what effect precursors like pro-vitamin-A carotenoids - plant pigments that the body converts into vitamin - would have when added to cultures of human oral cancer cells.

As a control, Schwartz decided to use lycopene, as it is a carotenoid, but the body does not convert it into vitamin A. To her surprise, she found that the tumour cells given lycopene died.

Cells lining the mouth are normally linked by tiny channels called gap junctions, which allow the cells to communicate. Healthy cells seem to detect unhealthy neighbours and order them to self-destruct, via the gap junctions. Cells in oral tumours lack gap junctions. This disrupts the protective mechanism and allows the tumour cells to proliferate unchecked. Schwartz.'s research reveals that lycopene restores the junctions. Other researchers had previously suggested that some carotenoids affect cancer in this way.

Having shown that lycopene kills oral cancer cells being grown in culture, Schwartz plans to test its effectiveness in people. Other research has shown that a diet high in fruit and vegetables also significantly reduces the risk of oral cancer.