Phytochemicals in apple fight cancer

A COMBINATION of plant chemicals, such as flavanoids and polyphenols - collectively known as phytochemicals - found both within the flesh of apple and particularly in the skin - provide the fruit's anti-oxidant and anti-cancer benefits, say Cornell food scientists. Their laboratory study, is published in Nature. "Scientists are interested in isolating single compounds - such as vitamin C, vitamin E and beta carotene - to see if they exhibit anti-oxidant or anti-cancer benefits. says Rui Hai Liu, Cornell assistant professor of food science.

An anti-oxidant is one of many chemicals that reduce or prevent oxidation, thus preventing cell and tissue damage from free radicals in the body. "In this research, we have shown the importance of phytochemicals to human health," says Liu's, Chang Yong Lee, Cornell professor of food science at the university's New York State Agricultural Experiment Station. "Some of the phytochemicals are known to be anti-allergenic, some are anti- carcinogenic, anti-inflammatory, anti-viral, anti-proliferative.

The researchers found that vitamin C in apples is only responsible for a small portion of the anti-oxidant activity. Instead, almost all of this activity in apples is from phytochemicals. Indeed, previous studies have shown that a 500 milligram vitamin C pill might act as a pro-oxidant. The Cornell researchers found that eating 100 grams of fresh apple with skins provided the total anti-oxidant activity equal to 1,500 milligrams of vitamin C. They used red delicious apples and compared the anti-cancer and anti-oxidant activity in the apple flesh, and also studied the fruit's skin.

Using colon cancer cells treated with apple extract, the scientists found that cell proliferation was inhibited. Colon cancer cells treated with 50 milligrams of apple extract (from the skins) were inhibited by 43 per cent. The apple flesh extract inhibited the colon cancer cells by 29 per cent.

The researchers also tested the apple extract against human liver cancer cells. At 50 milligrams, the extract derived from the apple with the skin on inhibited those cancer cells by 57 per cent, and the apple extract derived from the fruit's fleshy part inhibited cancer cells by 40 per cent.

"The consumption of whole fruits may provide the balanced anti- oxidants needed to quench reactive oxygen species," say the researchers. "Phytochemicals other than ascorbic acid (vitamin C)... contribute to the anti-oxidant activity of apples and to the capacity to inhibit tumor cell proliferation."

Lee while studying the enzymatic browning action of apples, identified a variety of phenolic compounds and learnt how these chemicals work during the browning action. Liu and Lee are working to study the antioxidant activity of various fruits and vegetables. They learnt that the amount of phenolic compounds in the apple flesh and in the skin varied from year to year, season to season and from growing region to growing region.

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