Download Flavonoids in Biological System

Flavonoids in Biological
System
BY
Dr. Gobinath Pandian
ABOUT FLAVONOIDS
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INTRODUCTION
STRUCTURE
PROPERTIES
SOURCE
TYPES
SYNTHESIS
ROLE
BIOLOGICAL EFFECTS
INTRODCTION
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The Flavonoids are most commonly known for their antioxidant activity.
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Flavonoids are "the most common group of polyphenolic compounds in the human diet
and are found ubiquitously in plants.
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They are secondary metabolites, meaning they are organic compounds that have
no direct involvement with the growth or development of plants.
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Flavonoids are becoming very popular because they have many health Promoting effects.
For examples : anti-allergic, anti-cancer, antioxidant, anti-inflammatory and anti-viral.
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Nutrition experts recommend eating flavonoid-rich foods rather than taking dietary
supplements containing large amounts of flavonoids.
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.
Structural difference
R1
HO
R1
O
R2
R2
O
HO
O
HO
R3
R3
R1
OH
O
OH
OH
O
R1
R1
R2
O
R1
R2
HO
O
R2
HO
O
R3
R3
R3
OH
OH
O
Flavanones
O
Flavonols
Iso-flavones
Flavones
HO
OH
OH
OH
OH
Flavanols
Anthocyanidins
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),
Major food sources for Flavanoids
The Fruits:
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
Common Dietary Flavonoids
Flavonoid
Subclass
Dietary
Flavonoids
Some Common
Food Sources
Anthocyanidins
Cyanidin, Delphinidin,
M
alvidin, Pelargonidin,
Peonidin, Petunidin
Red, blue, and purple berries;
red and purple grapes; red wine
Flavanols
Monomers (Catechins):
Catechins: Teas (particularly green
Catechin, Epicatechin,
E
and white), chocolate, grapes,
pigallocatechin,
berries, apples
Epicatechin gallate,
Epigallocatechin gallate
Dimers and Polymers:
Theaflavins,Thearubigins,
Proanthocyanidins
Flavanones
Hesperetin, Naringenin,
iodictyol
Theaflavins, Thearubigins:
Teas (particularly black)
Proanthocyanidins:
Chocolate, apples, berries,
red grapes, red wine
Er
Citrus fruits and juices,
e.g.,oranges, grapefruits, lemons
Flavonols
Quercetin, Kaempferol, M
Widely distributed:
yricetin, Isorhamnetin
yellow onions, scallions, kale, brocc
oli, apples, berries, teas
Flavones
Apigenin, Luteolin,
angeritin
T
Parsley, thyme, celery,
hot peppers,
Isoflavones
Daidzein, Genistein,
ycitein
Gl
Soybeans, soy foods, legumes
Structural difference
R1
HO
R1
O
R2
R2
O
HO
O
HO
R3
R3
R1
OH
O
OH
OH
O
R1
R1
R2
O
R1
R2
HO
O
R2
HO
O
R3
R3
R3
OH
OH
O
Flavanones
O
Flavonols
Iso-flavones
Flavones
HO
OH
OH
OH
OH
Flavanols
Anthocyanidins
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-coumaroylCoA.
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.
Synthesis of Flavonoids
Simplified presentation of Pathway
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.
Health benefits of Flavanoids
Fight against Heart Diseases
Health benefits of Flavanoids
Fight against obesity
Health benefits of Flavanoids
Fight against Diabetes
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.
THANK YOU