Transcript Shikimic Acid Pathway

Phenylpropanoids:
• Definition: Phenylpropanoids represent a large group
of natural products containing a phenyl ring attached
to a three-carbon propane side chain(C6-C3) in their
structure.
• Biosynthesis: Derived from the aromatic amino acids
phenylalanine and tyrosine or the intermediates of the
shikimic acid biosynthetic pathway.
• Categories: Simple Phenylpropanoids
(phenylpropenes, phenylpropyl alcohols,
phenylpropionaldehydes, phenylpropionic acids)
Simple phenylpropanoids
Phenylpropenes
OCH3
OCH3
H3CO
H3CO
H3CO
H3CO
HO
eugenol
anethole
OCH3
alpha-asarone
OCH3
beta-asarone
H3 CO
CH2OH
H3CO
HO
coniferol
phenylpropyl
alcohols
CHO
CH2OH
1-6
glc glc O
syringinoside
cinnamaldehyde
Phenylpropionaldehydes
Simple phenylpropanoids
phenylpropionic acids
HO
COOH HO
HO
HO
OH
C
O
COOH
HO
HO
ferulic acid
HO
O
C
O
HO
HOOC
rosmarinic acid
OH
O
O C
OH
OH
OH
HOOC
HO
OH
HOOC
OH
O
H3 CO
C
O
danshensu
caffeic acid
OH
O
COOH
3,4-dicaffeoyl quinic acid
chlorogenic acid
OH
OH
OH
HOOC
COOH
HO
OH
HO
OH
H3CO
OH
OH
quinic acid
OCH3
sinapic acid
Phenylpropanoid synthesis
Shikimic Acid Pathway
Phosphenolpyruvate
CO2H
OP
CH2
+
CHO
OH
OH
OP
Erythrose-4-phosphate
CO2H
OH
CH
CO2H
O
CH2
HO
HO
OH
OH
OP
OH
OH
OP
"Arabino" 7-phosphate
Shikimic Acid Pathway
CO2H
OH
CH
HO
HO
O
OH
OH
OP
CO2H
CO2H
OH
OH
5-Dehydroquinic Acid
-H20
O
OH
OH
5-Dehydro
shikimic acid
Shikimic Acid Pathway
CO2H
O
OH
OH
5-Dehydro
shikimic acid
CO2H
CO2H
HO
OH
PO
OH
OH
OH
Shikimic acid
5-PhosphoShikimic acid
Shikimic Acid Pathway
Phosphenolpyruvate
CO2H
OP
CH2
O
CO2H
HO2C
+
CO2H
O
-H2O
CO2H
-H2O
-CO2
OH
PO
OH
OH
Prephenic Acid
Phenylpyruvic Acid
Shikimic Acid Pathway
NH2
O
CO2H
Phenylpyruvic Acid
NH2
CO2H
CO2H
OH
L-Phenylalanine
L-Tyrosine
Shikimic Acid Natural Products
CH3
CH2
Eugenol
Anethole
CH3O
OMe
OH
CHO
CO2CH3
OH
Cinnamaldehyde
Methyl Salicylate
Phenylpropanoids:
– Flavonoids – water soluble plant pigments
– Anthocyanidins – improve microcirculation &
nightvision
– Coumarins - Anticoagulants
– Lignans – Anti-cancer drugs
– Tannins – in green tea, red raspberry & witch hazel
Structure and Classification:
•
Coumarins are lactones which are derived from phydroxycinnamic acids which undergo ortho hydroxylation then
ring closure between the ortho hydroxyl group and the carboxylic
group of the side chain, after a trans to cis isomerization of the
side chain double bond.
COOH
HO
p-hydroxycinnamic acid
5
4
8
O
1
6
7
coumarin
3
2
O
COOH
OH
cis-ortho-hyxroxycinnamic acid
• Coumarins are widely distributed in higher plants, and commonly
found in families such as the Umbelliferae (Apiaceae) and
Rutaceae, both in the free form and as glycosides.
Coumarins:
O
HO
O
Coumarin
O
O
7-Hydroxycoumarin
"Umbelliferone"
O
ONa
O
CH3
O
Warfarin Sodium
Lignans: Structure and Classification
• Lignans are typically found as dimeric
phenylpropanoids derivatives and are found in
woody tissues and resin of plants.
• Most of lignans are free form, seldom as
glycoside.
• They have antitumor, antiviral, liver protective,
etc. activities.
• The two phenylpropanoid units mostly linked
through the β-C atom of the C3 side chains.
Properties:
• Colourless crystal, no volatility, insoluble in
water, soluble in organic solvents.
• Optical Activity: one or more chiral center.
• The optical activity is related to biological
activities.
• The optical activity is easily changed by acid.
www.1ppt.com
LOGO
Structure and Classification
• Classification:
Simple Lignans
Monoepoxylignans
Lignanolides
Cyclolignans
Lignans
Cyclolignolides
Bisepoxylignans
Dibenzocyclooctene lignans
Biphenylene lignans
Other lignans
Shikimic Acid Lignins
HO2C
OH
OH
Catechol
Gallic Acid
OH
OH
OH
OH
OH
OH
O
HO
O
OH
O
O
O
MeO
OH
HO
OH
OMe
OH
Podophyllotoxin
(A Lignan)
OH
OH
O
OH
Procyanidin B-1
A
Lignan
(asynthetic
condensed
Tannin)
Lignin a complex phenolic
• Primary metabolite - secondary cell wall
component occurs in all vascular plants
• Structural function
• Also protective because deters herbivores due
to its toughness
• Blocks growth of many pathogens because
only small group of fungi can degrade
Lignin monomers
• Polymer of three phenolic alochols
• Different species have different ratios of these
monomers
• Lignin in beech has 100:70:7 of coniferyl: sinapyl:
para-coumaryl
Flavinoids
• One of the largest classes of phenolics
• Carbon skeleton has 15 carbons with two
benzene rings connected by a 3-C bridge
-C3-
Flavonoids
• Many have antimicrobial activity
– anti-bacterial, anti-fungal, and anti-viral
• Flavonoids in red wine responsible for the
“French Paradox” - lower risk of heart attacks
by inhibiting platelet aggregation and blood
clots
Flavinoids
• Flavinoids classified into different groups
based on the degree of oxidation of the 3-C
bridge
– Anthocyanins
– Flavones
– Flavonols
– Isoflavones
• Majority of flavinoids exist as glycosides
Shikimic Acid Flavones
OH
HO
HO
O
O
OH O
OH O
A Flavone
An Isoflavone
OH
+
HO
O
An Anthocyanidin
OH
OH
OH
Anthocyanins
• Colored flavinoids red, pink, blue,
purple pigments
• Attract animal
pollinators and
seed dispersers
Flavones and Flavonols
• Also flower pigments
• Absorb UV not visible light - not visible to
human eye but visible to many insects maybe be attractants, nectar guides
• Also present in leaves where they protect
against UV-B damage
• Appeared to be involved in legume roots in
attracting N-fixing bacteria
Isoflavonoids
• Some have strong insecticidal activity rotenoids
• Some have estrogenic/anti-estrogenic activity
and cause infertility in mammals
• Many are phytoalexins - antimicrobial cmpds
produced in response to bacteria and fungi
Soy isoflavones
• Isoflavones in soybean are thought
responsible for a host of beneficial effects
– lower cholesterol, especially LDL - thereby lower
risk of cardiovascular disease
– lower blood pressure
– estrogenic effects reduce symptoms of menopause
and reduce risks of osteoporosis
– inhibit growth of tumors and thought to be
responsible for low rates of breast and prostate
cancer among cultures eating soy products
Tannins
• Tannin a general name for a large group of complex
phenolic substances that are capable of tanning
animal hides into leather by binding collagen
• Found in almost every plant part - abundant in
unripe fruit
• Deter herbivores due to astringent properties - bind
saliva and other digestive proteins
• Antimicrobial - tannins in heart wood prevent decay
Tanins