Purple tomato with snapdragon gene could fight cancer

By Elizabeth Weise, USA TODAY

British researchers have used genes from the snapdragon flower to increase tomatoes' cancer-fighting powers.

When the genes were added, the tomatoes ripened to an almost eggplant purple. They contain very high levels of antioxidant pigments called anthocyanins. Cancer-prone mice fed the altered tomatoes lived significantly longer than those that didn't get them.

The genetic engineering was minimal, says Cathie Martin, the plant geneticist who led the work. Tomatoes already make their own anthocyanins. The genes from the snapdragon flowers acted as a switch to turn that production on full blast, says Martin, who is based at the John Innes Centre, an independent plant research center in Norwich, England.

The tomatoes produce levels of anthocyanins about on par with blackberries, blueberries and currants, which recent research has touted as miracle fruits. But because of the high cost and infrequent availability of such berries, tomatoes might be a better source, says Martin.

The researchers fed 20 mice bred to be cancer-prone a diet that consisted of 10% powder from the genetically engineered tomatoes, with other groups getting no tomatoes and red tomatoes. The mice who got the tomato powder lived on average 30% longer than those that didn't.

The researchers acknowledge the findings are very preliminary.

The tomatoes would have to go through years of regulatory processes to end up in supermarkets, says biotechnology project manager Greg Jaffe of the Center for Science in the Public Interest. Jeffrey Blumberg, director of the Antioxidants Research Laboratory at Tufts University in Medford, Mass., cautions that it would be a "big leap" to sa...