of New and Unusual
expressed genes from snapdragon in tomatoes to grow purple tomatoes
high in health-protecting anthocyanins.
Anthocyanins are naturally occurring pigments found at particularly
high levels in berries such as blackberry, cranberry and chokeberry.
Scientists are investigating ways to increase the levels of
health-promoting compounds in more commonly eaten fruits and vegetables.
"Most people do not eat 5 portions of fruits and vegetables a day, but
they can get more benefit from those they do eat if common fruit and
veg can be developed that are higher in bioactive compounds," says Prof
Cathie Martin from the John Innes Centre.
offer protection against certain cancers, cardiovascular
disease and age-related degenerative diseases. There is evidence that
anthocyanins also have anti-inflammatory activity, promote visual
acuity and hinder obesity and diabetes
Tomatoes already contain high levels of the antioxidant lycopene.
Highly processed tomatoes are the best source, or tomatoes cooked in a
little oil, which helps to release the lycopene from cells. Flavonoids
meanwhile are soluble in water, and foods containing both water soluble
and fat-dissolved antioxidants are considered to offer the best
protection against disease.
In this study the scientists expressed two genes from snapdragon that
induce the production of anthocyanins in snapdragon flowers. The genes
were turned on in tomato fruit. Anthocyanins accumulated in tomatoes at
higher levels than anything previously reported for metabolic
engineering in both the peel and flesh of the fruit. The fruit are an
intense purple colour.
The scientists tested whether these elevated levels actually had an
effect on health. In a pilot test, the lifespan of cancer-susceptible
mice was significantly extended when their diet was supplemented with
the purple tomatoes compared to supplementation with normal red
"This 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," says Professor Cathie Martin.
"And certainly the first example of a GMO with a trait that really
offers a potential benefit for all consumers. The next step will be to
take the preclinical data forward to human studies with volunteers to
see if we can promote health through dietary preventive medicine
Innes Centre , an independent,
world-leading research centre in plant and microbial sciences based on
Norwich Research Park.
to Grow Juicy Tasty Tomatoes
from the producer
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