Tuesday, March 23, 1999 Published at 19:10 GMT
The citrus cancer beaters
Fruit - always healthy - could have additional benefits
A chemical found in the skin of citrus fruits could have significant health benefits, scientists said on Tuesday.
It may even halt the spread of cancer.
Researchers think citrus limonoids may be responsible for health effects that may previously have been attributed to vitamin C.
The substance is present in commercially produced citrus fruit drinks at about the same level as the vitamin.
As well as combating cancer, limonoids have been shown to reduce cholesterol levels. They have even shown potential as an agricultural aid.
The national meeting of the American Chemical Society heard more than a dozen papers about the potential benefits of limonoids.
Limonoids are compounds found in citrus fruits, usually in the peels. They are responsible for the familiar bitter taste.
Scientists are exploring their use more fully after preliminary research found limonoids could prevent and halt cancer under laboratory conditions.
They produced anti-cancer effects in animals and prevented the spread of human breast cancer in a cell culture.
Some scientists think they may be able to halt the spread oral cancer, while some advocates of the compound suggest limonoid creams could be used to defeat skin cancer.
Following the demonstration of their anti-cancer properties in animals, companies have developed new foods that are rich in limonoid glucosides.
One such example is the Wakayama Prefectual Federation of Agricultural Co-operatives in Japan.
It produced an orange juice drink containing about triple the concentration of limonoid glucosides.
Establishing the levels of benefits
But scientists want to find out if the compound really will produce the same anti-cancer effects in the human body.
The researchers who demonstrated the effects of limonoids on breast cancer have progressed to trials in mice, they reported.
Another team are testing the performance of 12 limonoids in preventing cancer in humans.
The compound is thought to have other benefits too.
One study looked at its effects at reducing cholesterol levels.
It found that when rabbits were given orange juice and orange juice instead of water, their level of low-density cholesterol fell.
The researchers tested the limonoids in the juices and their results suggest the compounds were responsible for the drop.
The last area examined was the agricultural potential of the compound - they have even shown the ability to scare off insects.
Researchers presented a paper that showed field tests of limonoids can get rid of Colorado potato beetles in levels not poisonous to plants.
The American Chemical Society national meeting is being held in Anaheim, California.
It continues until Thursday.