The effects of plant flavonoids on mammalian cells: Implications for inflammation, heart disease, and cancer

Flavonoids are nearly ubiquitous in plants and are recognized as the pigmen ts responsible for the colors of leaves, especially in autumn. They are ric h in seeds, citrus fruits, olive oil, tea, and red wine. They are low molec ular weight compounds composed of a three-ring structure with various subst itutions. This basic structure is shared by tocopherols (vitamin E). Flavon oids can be subdivided according to the presence of an oxy group at positio n 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in pos ition 3 of the C (middle) ring. These characteristics appear to also be req uired for best activity, especially antioxidant and antiproliferative, in t he systems studied. The particular hydroxylation pattern of the B ring of t he flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been u sed for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet use d flavonoids therapeutically, even though their safety record is exceptiona l. Suggestions are made where such possibilities may be worth pursuing.