The most significant group of biologically active botanical molecules are the flavonoids.
The flavonoids are a library of molecules that are widely distributed among various plant species.
Over 2000 individual chemicals have been isolated, investigated and tested.
Flavonoids as a group are potent antioxidants with specific ones also capable of inhibiting the metabolism of certain carcinogens.
Flavonoids are more pharmacologically diverse and more powerful than carotenoids. Catechins for example, which are found in green tea, are a specific type of flavonoid. Catechins are biologically very active and are classified as polyphenols based on the presence of a phenol ring in its chemical structure.
Flavonoids found in bilberry, black currant and grapes are called anthocyanosides and proanthocyanidins. These flavonoids provide significant collagen-stabilizing activity.
Collagen provides tensile strength to eye tissues. Reinforced cross-linkage strengthens collagen. This strength combined with the free radical suppression, and inhibition of histamine and prostaglandin secretion that flavonoids produce, improves the health of the tissue.
This explains the mechanism of anthocyanidins and why prolonged use of these foods is advantageous to muscles, ligaments and bones. Anthocyanidins are also believed to improve blood glucose and insulin levels, two factors important to diabetics.
Flavonoids are grouped into the following types.
1. Flavones (tangeretin and nobiletin) are found in citrus fruits and are believed to modify cytochrome P450 enzymes and inhibit the invasiveness of certain tumors.
2. Flavonols (quercetin and kaempferol) are found in cereal grains and vegetables are potent inhibitors of P450 reactions. Quercetin has been shown to inhibit the lipoxygenase pathway of arachidonic acid metabolism, while producing a lesser inhibitory effect on the cyclooxygenase system.
3. Polyphenols (catechins) are found in green tea. They have been reported to inhibit the formation of nitrosamines. Nitrosamines are formed when nitrites, used in the curing of ham and bacon, combine with amino acids. Nitrosamines are known carcinogens.
4. Flavonones (naringin) are found in high concentration in grapefruit and are anti-carcinogenic.
5. Isoflavones, found in soybeans, are considered cancer protective foods. Isoflavones are hormone-like compounds with weak estrogenic and antioxidant activity. Genistein, isolated from soybeans, inhibits numerous enzyme systems and retards the blood supply to cancer cells.
6. Stilbenes are flavonoid-like compounds synthesized by grapes and berries and thought to repress cancer growth.
One of the most important compounds found in plants are the polyphenols. Polyphenols were once designated as Vitamin P because of its importance to good health.
These compounds are all characterized by the presence of more than one, aromatic compound called a phenol group. Polyphenols are predominant in the skin of fruits. They are found in berries, tea, grapes, olives, cocoa and walnuts.
Polyphenols are divided into tannins and flavonoids.
Catechins (Green Teal Polyphenols)
Green tea is unfermented tea. It contains polyphenols that are very strong antioxidants. One type of green tea polyphenol (catechins) help prevent cancers of the gastrointestinal tract and crosses the blood-brain barrier to neutralize free radicals.
Polyphenols are very powerful antioxidants. In fact, the anti-atherogenic effect of green tea may be due to its preventing the oxidation of LDL-cholesterol (lousy cholesterol) and preventing its conversion into the truly lousy form of cholesterol.
Green tea catechins are also inhibitors of tyrosine kinase, the enzyme that phosphorylates proteins, which is essential for cell mitosis. This is believed to be the mechanism by which catechins prevent cancers of the gastrointestinal tract.
Grape Antioxidants (Reservatrol)
The polyphenol found in wine is the antioxidant known as reservatrol (resorcinol). It is synthesized by the plant and stored in the skin of the red grape. Reservatrol is at least partially responsible, for the “French Paradox”. The observation that the incidence of coronary heart disease is relatively low among the French despite their high intake of saturated fat.
Chocolate and Cocoa have long been thought of as a pleasure food and aphrodisiac. In addition to its high calorie content, which becomes even higher with the commercial addition of sugar and fat, this food contains many phytonutrients.
The presence of polyphenols in dark or unprocessed Chocolate may provide healthy, beneficial effects. One such polyphenol is epicatechin.
Epicatechins are powerful antioxidants that specifically protects LDL-cholesterol from oxidation. LDL-cholesterol is the lousy form of cholesterol and by preventing its oxidation into a horrific form, atherosclerosis or the blockage of blood vessels may be prevented.