FLAVONOIDS

Chemical structure

nThe flavonoids are polyphenolic compounds possessing 15 carbon atoms; two benzene rings joined by a linear three carbon chain.
nThe skeleton below, can be represented as the
nC6 - C3 - C6 system.

nFlavonoids constitute one of the most characteristic classes of compounds in higher plants.
nMany flavonoids are easily recognised as flower pigments in most angiosperm families (flowering plants).
nHowever, their occurence is not restricted to flowers but include all parts of the plant.

nThe chemical structure of flavonoids are based on a C15 skeleton with a CHROMANE ring bearing a second aromatic ring B in position 2, 3 or 4.

nIn a few cases, the six-membered heterocyclic ring C occurs in an isomeric open form or is replaced by a five - membered ring.


Flavonoids

nAnthocyanidins (e.g., cyanidin, pelargonidin)
nCatechins or flavanols (e.g., epicatechin, gallocatechin)
nFlavones (e.g., apigenin, luteolin) see Sytrinol for healthy cholesterol
nFlavonols (e.g., kaempferol, myricetin, quercetine) Quercetin
nFlavanones (e.g., hesperidin, naringenin)
nIsoflavones (e.g., genistein, daidzein) Genistein and Daidzen


Sources of Flavonoids

nFlavonoids are a class of water-soluble pigments and are found in a wide variety of plant products such as fruit, vegetables, herbs, nuts, and tea...including chocolate.
nThere are more than 4,000 flavonoid compounds; flavonoids are under a subgroup of a large class called polyphenols.


Examples of Flavonoids sources


Anthocyanidins
eg. cyanidin and delphinidin
- derived from berries, grapes and fruit skins


Flavones
eg. apigenin and luteolin
- derived from herbs and tea


Flavanones
eg. hesperetin and naringenin
- derived from citrus


Flavonols
eg. myricetin and quercetin
- derived from fruits; apples, onions and botanicals


Isoflavones
eg. genistein and diadzein
- derived from soy product



nQuercetine
- found in onions and apples
- also serves as a building block for other flavonoids. Rutin
and hesperidin are the most active of the so-called citrus or
flavonoids, which, as the name suggests, are present in
oranges, grapefruits, tangerines, and other citrus fruits.
nOther flavonoids include PCOs (or procyanidolic oligomers: also called proanthocyanidins)
- anthocyanosides, polyphenols, and genistein
- PCOs are plentiful in pine bark and grape seed extracts
(pine bark extracts are available as pycnogenol) and in red
wine.
Anthocyanosides are found in the herb bilberry, purple cabbage
and grapes


Green tea is the primary source of polyphenols, especially
EGCG (epigallocatechin-gallate), which experts believe is
possibly the most effective cancer-fighting compound yet
discovered. Genistein, found in soy products, has
antioxidant properties and can also mimic the effects of
estrogen.
Without question, some of the best research on flavonoids
has been conducted by Japanese scientists investigating
their national beverage: green tea. Tea is rich in a variety of
gallate compounds, but the most active antioxidant among
them appears to be epigallocatechin gallate. It accounts for
about 30 percent of the flavonoids in green tea.


Chocolate
nThere have been many studies linking cocoa with health benefits. The darker chocolate with the most concentrated cocoa will of course be the most beneficial.
nFlavonoids and the subgroup called catechins or flavanols are found in dark chocolate at four times the amount that is found in green tea. Antioxidants block the free radicals that are breakdown normal cell reproduction.


Before you grab a chocolate candy bar or slice of chocolate
cake, let’s look at some characters of chocolate
over others:
nWhen cocoa is processed into your favorite chocolate products, it goes through several steps to reduce its naturally pungent taste. Flavonoids (polyphenols) provide this pungent taste. The more chocolate is processed (such as fermentation, alkalizing, roasting), the more flavonoids are lost.
nUntil now, dark chocolate appears to retain the highest level of flavonoids. So your best bet is to choose dark chocolate over milk chocolate.
nSome chocolate manufacturers are studying ways to retain the highest level of flavonoids while still providing acceptable taste. Stay tuned for more information in this area.