Possible Cancer-Fighting Properties Found in Certain
Bioflavonoids By Jesús García
August 9, 2000
Orange and other citrus juices contain compounds that may help the
body fight off cancer-causing substances, Agricultural Research Service scientists
The citrus compounds, called bioflavonoids, not only give citrus
juice its flavor and color but are potent antioxidants, according to ARS
scientists Hamed Doostdar and Richard Mayer. Theyre with the
Research Laboratory in Ft. Pierce, Fla.
The scientists have identified several bioflavonoids from citrus
that inhibit certain cytochrome P450 enzymes. Thwarting these enzymes is
important, because some of them can turn cigarette smoke, pesticides and other
substances into carcinogens. Cigarette smoke and pesticides are called
procarcinogens--meaning they may not cause cancer in their original form but
could become carcinogenic later inside the body.
One P450 enzyme, known as P450 1B1, turns procarcinogens into
carcinogens. It is also present at high levels in breast and prostate cancer
cells, and can even modify the female hormone estradiol into a possible
The ARS scientists have found that hesperetin, the most abundant
bioflavonoid in orange juice, inhibits the P450 1B1 enzyme from metabolizing
procarcinogens, reducing the chances that the body could turn these substances
Hesperetins effect on enzyme P450 1B1 might lead to the
development of alternatives to traditional cancer chemotherapy treatments that
affect healthy as well as diseased cells. Only cells containing the enzyme P450
1B1, which are largely cancer cells, would be affected by hesperetin.
ARS is the U.S. Department of
Agricultures principal scientific research agency.
Scientific contact: Richard Mayer,
Research Laboratory, Ft. Pierce, Fla., phone (561) 462-5897, fax (561)