Purple tomatoes the latest in the arsenal against cancer

British scientists have developed purple tomatoes which they believe may possibly help fight cancer.

The purple tomatoes, developed by a team from the John Innes Centre, Norwich, are rich in an antioxidant pigment called anthocyanin which is thought to have anti-cancer properties.

In a study carried out by the team it was found that found mice fed the tomatoes lived longer and the researchers suggest the vegetable has the potential to promote health through diet by reducing the impact of chronic disease.

Lead study author Dr. Eugenio Butelli says in order to obtain the purple tomato fruit, rich in anthocyanins, two genes from the snapdragon flower - Delila and Rosea1- were the perfect combination to produce anthocyanins, the same phytochemical found in blueberries.

Dr. Eugenio Butelli says their purple tomato has almost triple the level of anthocyanins in comparison to the natural fruit.

Anthocyanins are found in particularly high levels in berries such as blackberry, cranberry and chokeberry, and research has shown they to help significantly slow down the growth of colon cancer cells.

Other research has indicated anthocyanins offer protection against cardiovascular disease and age-related degenerative diseases and the anti-inflammatory properties in the pigments are thought to help boost eyesight and ward off obesity and diabetes.

The John Innes team are collaborating with other European centres in the FLORA project which is investigating ways to increase the levels of health-promoting compounds in more commonly eaten fruits and vegetables.

Tomatoes are already known to contain high levels of beneficial antioxidant compounds, such as lycopene and flavonoids and according to Professor Cathie Martin, as most people do not eat five portions of fruits and vegetables a day, they may get more benefit from those they do eat if common fruit and vegetables can be developed that are higher in bioactive compounds.

Tests on mice specially bred to be susceptible to cancer showed that animals whose diets were supplemented with the purple tomatoes had a significantly longer lifespan compared to those who received only normal red tomatoes.

Professor Martin says the research is one of the first examples of metabolic engineering that offers the potential to promote health through diet by reducing the impact of chronic disease and is also the first example of a genetically modified organism with a trait that really offers a potential benefit for all consumers.

The researchers say though the results appear promising they remain cautious as although the mice fed purple tomatoes lived longer it is still unclear how and it is unlikely everything can be explained on antioxidants basis alone.

They also say the possible toxic effects have not been taken into account and at this stage they are a long way from considering a human trial and the next step will be to investigate the effect of purple tomatoes on different kinds of tumour models to define how they act.

Cancer experts say it is too early to say whether anthocyanins obtained through diet could help to reduce the risk of cancer.

The FLORA Project is funded by the European Commission and aims to gain evidence on the dynamics triggered by flavonoids and their link to heart disease and cancer.

FLORA scientists are researching the field of flavonoids contained in different vegetables, such as corn, tomatoes and an experimental plant called Arabidopsis and oranges.

The finding by the FLORA European Project is published in the journal Nature Biotechnology.