1. Flavonoids in Biological SystemBY
Dr. Gobinath Pandian

2. ABOUT FLAVONOIDS INTRODUCTION STRUCTURE PROPERTIES SOURCE TYPES
SYNTHESIS
ROLE
BIOLOGICAL EFFECTS

3. INTRODCTION
The Flavonoids are most commonly known for their antioxidant activity.
Flavonoids are "the most common group of polyphenolic compounds in the human diet
and are found ubiquitously in plants.
They are secondary metabolites, meaning they are organic compounds that have
no direct involvement with the growth or development of plants.
Flavonoids are becoming very popular because they have many health Promoting effects. For examples : anti-allergic, anti-cancer, antioxidant, anti-inflammatory and anti-viral.
Nutrition experts recommend eating flavonoid-rich foods rather than taking dietary supplements containing large amounts of flavonoids.

4. Structure and Properties
Flavonoids are water soluble polyphenolic molecules containing 15 carbon atoms.
Flavonoids belong to the polyphenol family. Flavanoids can be visualized as two benzene rings which are joined together with a short three carbon chain.
One of the carbons of the short chain is always connected to a carbon of one of the benzene rings, either directly or through an oxygen bridge, thereby forming a third middle ring, which can be five or six-membered.
The flavonoids consist of 6 major subgroups: chalcone, flavone, flavonol, flavanone, anthocyanins and isoflavonoids.
Together with carotenes, flavanoids are also responsible for the coloring of fruits, vegetables and herbs.

5. Structural difference
Iso-flavones
Flavonols
Flavones
Flavanones
Flavanols
Anthocyanidins

6. Source
Flavonoids are found in most plant material.
The most important dietary sources are fruits, tea and soybean.
Green and black tea contains about 25% percent flavonoids.
Other important sources of flavonoids are apple (quercetin), citrus fruits (rutin and hesperidin),

7. Major food sources for Flavanoids
The Fruits:

9. Types/List of Flavonoids
Flavonoids, a subclass of polyphenols, are a group of phytochemicals that are among the most potent and abundant antioxidants in our diet.
FLAVONOLS: myricetin and quercetin
FLAVONES: apigenin and luteolin
FLAVANONES: hesperetin and naringenin
FLAVAN-3-OLS: catechin, epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate
ANTHOCYANIDINS: cyanidin, delphinidin, malvidin, pelargonidin, peonidin

10. Common Dietary Flavonoids
Flavonoid Subclass
Dietary Flavonoids
Some Common Food Sources
Anthocyanidins
Cyanidin, Delphinidin, Malvidin, Pelargonidin, Peonidin, Petunidin
Red, blue, and purple berries; red and purple grapes; red wine
Flavanols
Monomers (Catechins): Catechin, Epicatechin, Epigallocatechin, Epicatechin gallate, Epigallocatechin gallate
Dimers and Polymers: Theaflavins,Thearubigins,
Proanthocyanidins
Catechins: Teas (particularly green and white), chocolate, grapes, berries, apples
Theaflavins, Thearubigins:
Teas (particularly black)
Proanthocyanidins:
Chocolate, apples, berries,
red grapes, red wine
Flavanones
Hesperetin, Naringenin, Eriodictyol
Citrus fruits and juices,
e.g.,oranges, grapefruits, lemons
Flavonols
Quercetin, Kaempferol, Myricetin, Isorhamnetin
Widely distributed:
yellow onions, scallions, kale, broccoli, apples, berries, teas
Flavones
Apigenin, Luteolin, Tangeritin
Parsley, thyme, celery,
hot peppers,
Isoflavones
Daidzein, Genistein, Glycitein
Soybeans, soy foods, legumes

11. Structural difference
Iso-flavones
Flavonols
Flavones
Flavanones
Flavanols
Anthocyanidins

12. General biosynthetic pathway of FLAVONOIDS
SYNTHESIS
General biosynthetic pathway of FLAVONOIDS
Flavonoids are synthesized by the phenylpropanoid metabolic pathway in which the amino acid phenylalanine is used to produce 4-coumaroyl-CoA.
This can be combined with malonyl-CoA to yield the true backbone of flavonoids, a group of compounds called chalcones which contain two phenyl rings
Along this pathway many products can be formed, including the flavonols, flavan-3-ols, proanthocyanidins (tannins) and a host of other
polyphenolics.

13. Synthesis of Flavonoids

14. Simplified presentation of Pathway

15. Role of flavonoids:
Flavonoid intake from vegetables, fruit, berries and beverages has been favorably linked with reduced risks of a number of diseases
Antioxidants can be called as a natural defence mechanism in living organisms. Antioxidants are molecules which can safely interact with free radicals and terminate the chain reaction before vital molecules are damaged.

16. Health benefits of Flavanoids
Fight against Heart Diseases

17. Health benefits of Flavanoids
Fight against obesity

18. Health benefits of Flavanoids
Fight against Diabetes

19. Dietary Function of Flavonoids
Flavonoids are plant phytochemicals that cannot be synthesized by humans.
Dietary intake estimates vary from 23 mg/day to 1000 mg/day have demonstrated that flavonoids have antioxidant and antimutagenic activities.

20. THANK YOU