Bioflavonoids (Salem Health: Cancer)
Nutrition: The principal food sources of bioflavonoids are apples, celery, onions, green and black tea, citrus fruits, berries, soy, red wine, and cocoa. Although bioflavonoids are resistant to heat, certain food manipulations, such as the peeling of fruits or boiling, can cause some loss of their content or bioavailability. After the sugar moiety is removed by enzymes of the gastrointestinal tract, a variable portion of the ingested bioflavonoids is readily absorbed. The absorbed bioflavonoids are metabolized in the liver by conjugation with other chemical groups (for example, glucuronic acid, sulfate, or methyl groups) and converted to smaller compounds.
Bioflavonoids and cancer: Numerous studies in experimental models, both in vivo and in vitro, have suggested that bioflavonoids have anticarcinogenic potential. As effective antioxidants, they prevent mutagenesis and tumor promotion by protecting deoxyribonucleic acid (DNA) and proteins from oxidative damage. By acting on signal transduction pathways that control the cell cycle, bioflavonoids inhibit proliferation and stimulate apoptosis, that is, programmed death, of human cancer cells. Cell cycle-related actions performed by bioflavonoids include suppressing nuclear factor kappa B activation, inhibiting mitogen-activated protein kinases, and blocking epidermal growth factor signaling. Bioflavonoids also stimulate detoxifying enzymes, such as cytochrome...
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Bioflavonoids (Encyclopedia of Alternative Medicine)
Bioflavonoids, or flavonoids, are a large class of antioxidants. They are compounds abundant in the pulp and rinds of citrus fruits and other foods containing vitamin C, such as soybeans and root vegetables. Other major sources of bioflavonoids include tea, vegetables such as broccoli and eggplant, flaxseed, and whole grains. Bioflavonoids are active ingredients in many herbal remedies. These include feverfew, Tanacetum parthenium; Ginkgo biloba; licorice root, Glycyrrhiza glabra; St. John's wort, Hypericum perforatum; and Echinacea spp.
Bioflavonoids help maximize the benefits of vitamin C by inhibiting its breakdown in the body. In 1935, Albert Szent-Györgyi demonstrated that an extract he called citrin, made from lemon peels, was more effective than pure vitamin C in preventing scurvy. In 1936, Szent-Györgyi found that citrin was a mixture of bioflavonoids, including the flavone hesperidin and a flavonol glucoside. Szent-Györgyi believed that bioflavonoids should be considered vitamins, but was not able to substantiate that they were essential nutrients. Still, many researchers and physicians believe that dietary intake of bioflavonoids is beneficial for blood vessel health and possibly for protection against heart disease.
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