2. Lower FA vs. Higher FA?
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Unsaturated FA
Mono unsaturated FA
Polyunsaturated FA
Linoleic acid
(2 double bonds)
Linolenic acid
(3 double bonds)
Arachidonic acid
(4 double bonds)
3. 1. Linoleic acid
2. a-linolenic acid
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Supplied through the diet. Found only in the oils originating from plant.
5. Role in inflammatory response: redness, swelling, pain.
Destroy invading organisms and helps in repair.
Helps in smooth muscle contraction.
Increase water and sodium excretion.
Acts as a modulator – bronchoconstrictor,
bronchodialator
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6. Eicosa: (Greek) = 20.
Precursor of eicosanoids: Polyunsaturated fatty acids.
Are chemical messengers.
Chemical messengers: neurotransmitters, cytokines,
hormones, retinoid, eicosanoids, and growth factors.
Needs receptors: either plasma membrane or intracellular
binding protein.
E.g. Ion-channel receptor, tyrosine kinase receptor.
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7. Produced only when necessary
Not stored in body
Extremely short half-life
Biological action mediated by G-protein coupled
receptor – different in different cells
Acts locally
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8. Required for synthesis of prostaglandin, thromboxane, leukotriene,
and lipoxin.
Compromises mitochondrial membrane integrity.
Low level of DHA: RETINITIS PIGMENTOSA.
EFA deficiency is exacerbated by trans-fatty acids.
EFA deficiency can be reversed by administering Vitamin B / fat-free
liver extract in diet.
Source of trans-fatty acids: ruminant fat (E.g. butter: 2-7%) arise
from action of microorganism present in rumen.
Main source: vegetable oil (partially hydrogenated vegetable oil)
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9. Takes part in inflammatory response: infection/injury
E.g. forming blood clot, pain, swelling, and fever.
Takes part in smooth muscle contraction (intestine, uterus)
Increase water retention, sodium excretion, regulation of blood
pressure.
Acts as modulator (Activator & Repressor)
Blood vessel constrictor as well as dilator
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10. Synthesized in small amount
Action is localized
Not synthesized by special gland
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12. PG + third letter.
PG: Prostaglandin + A, C, D,
F.
No. represents bonds.
Nomenclature: 4 things to
care about
No. of carbon atoms, no. of
bond`s, position of bonds,
carbon no. containing bond.
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18. 5 carbon ring structure
Originated from arachidonic acid
Name derived from prostate gland
2 groups of prostaglandins were originally defined as
PGE (Ether-soluble) and PGF (Buffer-soluble)
Each group contains numerous subtypes: PGE1, PGE2,
PGF …
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19. Six membered, ring containing an ether
Are produced by platelets (called
thrombocytes)
Act in formation of blood clot
And reduction of blood flow to the site of clot
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20. First found in leukocytes
Contains 3 conjugated double bonds
They are powerful biological signals
For example: leukotriene D4 derived from leukotrienes
A4, helps induces contraction of smooth muscle lining,
the muscle lining of airways to lungs.
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Over production of leukotrienes causes asthmatic
attacks. Leukotrienes production is the one target of
antiasthmatic drugs.
21. Synthesized by almost all cells.
From: Polyunsaturated fatty acids with 20-carbon atom.
Fatty acids esterified with membrane phospholipids
Dietary precursor of prostaglandin: Linoleic acid
Linoleic acid elongation desaturation
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22. Most common: Archidonic acid
E.g. Eicosatetraenoic acid (Polyunsaturated, 20 carbons, 4
double bonds)
Archidonic acid is not synthesized in body, have to be
supplied in diet.
Dietary source: Linoleate present in plant oils.
Diet affect cell membrane composition.
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23. 3 pathways: COX, LOX, cytochrome p450
COX prostaglandin and thromboxane
LOX leukotriene, lipoxin and HETE
Structure of Prostaglandin and Thromboxane
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31. Saturday, August 6, 2016 Rajesh Chaudhary 31
Trihydroxy
derivative of
arachidonic acid.
32. Synthesis of prostaglandin are partially controlled.
How?
Self-catalyzed destruction switch off PG synthesis.
Function of 15-hydroxyprostaglandin dehydrogenase
Inaction of 15-hydroxyprostaglandin dehydrogenase:
sulfasalazine/ indomethacin.
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33. Half-lives (t1/2) = seconds to minute
Oxidation of hydroxy group ketone group
Double bond at C13 is reduced.
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34. Inhibited by structurally unrelated compounds
E.g. Corticosteroids (Cortisol)
Non-steroidal anti-inflammatory drugs
Aspirin inhibits PG synthesis
Aspirin – irreversibly blocks synthesis of
cyclooxygenase
Indomethacin & Phenylbutazone – reversibly blocks
synthesis of cyclooxygenase.
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35. Short half life – may be minutes or so.
Site of degradation: liver and lungs.
Enzymes responsible: 15-a-hydroxy PG
dehydrogenase and 13-PG reductase converts
hydroxyl group at C15 to keto group then C13 and C14
dihydroxy derivatives.
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36. Prostacyclin: vasodilator, inhibits platelets formation
PGF2 stimulates uterine muscle termination of pregnancy
PGF constrictor of broncho smooth muscle
PGE: Bronchodilator
PGE2 and D2 inflammatory response, capillary permeability
PGs in general inhibits gastric secretion
PGE2 lipolysis, calcium mobilization, glycogen synthesis
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38. Signaling molecule binds to cell-surface receptor
signals release of phospholipase phospholipase
cleaves phospholipids of cell membrane production of
eicosanoids
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