A comprehensive presentation on the essential fatty acids suitable for medical undergraduates and faculty.

1. LIPID CHEMISTRY
DR ROHINI C SANE
PROFESSOR
DEPARTMENT OF BIOCHEMISTRY
D Y PATIL MEDICAL COLLEGE EBENE

2. PROPERTIES OF ESSENTIAL FATTY ACIDS (EFA )
• HYDROGENATION (UNSATURATED --- SATURATED FATTY
ACIDS(SOLIDIFICATION )
• LINOLENIC ACID (3 = BONDS)+ 2HLINOLEIC ACID (2 =BONDS )
• LINOLEIC ACID (2 =BONDS )+2 HOLEIC ACID (1 = BOND )
• OLEIC ACID (1 = BOND ) +2 HSTEARIC ACID (NO = BOND)—
SATURATED FATTY ACID

3. PROPERTIES OF ESSENTIAL FATTY ACIDS (EFA )
• NOT SYNTHESIZED IN BODY
• TO BE SUPPLIED IN DIET (ESSENTIAL)---HUMAN BODY DOSE NOT
HAVE ENZYMES TO ADD DOUBLE BOND BEYOND POSITION 9
• LINOLEIC ACID18 ,2,(9,12)
• LINOLENIC ACID 18,3,(912,15)
• ARACHIDONIC ACID 20 4,(5,8,11,14)
• ARACHIDONIC ACID -- LINOLENIC ACID (PARTIALLY SYNTHESIZED
IN HUMAN BODY)

4. PROPERTIES OF FATTY ACIDS (EFA )
• II HYDROGENATION
• UNSATURATED FATTY ACIDS + 2 HALOGEN ATOMS >HALOGENATED
DERIVATIVE (eg DI IDOOLEIC ACD)
III MELTING POINT
• SHORT & MEDIUM CHAIN ---LOW MELTING POINT
• LONG CHAIN ----HIGH MELTING POINT
• INCREASE IN CHAIN LENGTH ---MELTING POINT &BOILING POINT
INCREASES
• STEARIC ACID (18C)---69οC, OLEIC ACID (1= BOND ) 15 ο C
• INCREASE IN CHAIN LENGTH----SOLUBILTY DECREASES (BILE SALTS
NEEDED FOR ABSORPTION )
•

8. PROPERTIES OF FATTY ACIDS (EFA )
IV SALT FORMATION WITH ALKALI
• CH3COOH + NaOH -CH3COONa+ H2O
• LONG CHAIN FATTY ACID + NaOH -SOAP (INSOLUBLE)
• CALCIUM /MAGNESIUM SALTS---- >GREASE

9. PROPERTIES OF FATTY ACIDS (EFA )
V ESTER FORMATION
• FATTY ACIDS +ALCOHOL(GLYCEROL ) -- ESTER
• (GLYCEROL )+ FATTY ACIDS -- MONOACYL GLYCEROL
• MONOACYL GLYCEROL +FATTY ACIDS ----DIACYL GLYCEROL
• DIACYL GLYCEROL + FATTY ACIDS ----->TRIACYL GLYCEROL

11. Isomerization of unsaturated fatty acids
Geometrical isomerization
• I Acyl groups are on same side of double bond –cis isomers –oleic
acid –less stable
• II I Acyl groups are on opposite side of double bond—trans isomers –
Elaidic acid—more stable
• MCQ ---CIS ISOMERS PACK THE MEMBRANE STRUCTURE.
• Naturally occurring unsaturated fatty acids exist in cis forms.
•

12. OXIDATION OF FATTY ACIDS
• SATURATED FATTY ACIDS -----BETA OXIDATION---ATP
• UNSATURATED FATTY ACIDS ---AUTOOXIDATION (REACTIVE DOUBLE BONDS )
• PEROXIDES
• ENEDIOLS
• EPIOXIDES
• ALDEHYDES
ANTIOXIDANTS PREVENT OXIDATION OF FATTY ACIDS
• BHA ---BUTYLATED HYDROXY ANISOL
• BHT ----BUTYLATED HYDROXY TOLUENE
• VITAMIN E
• PROPYL GALLATE
HYDROQUINONE

13. FUNCTIONS OF ESSENTIAL FATTY ACIDS (EFA )
• MEMBRANE STRUCTURE
• CHOLESTEROL TRANSPORT
• FORMATION OF LIPOPROTEINS
• PREVENTION OF FATTY LIVER
• FORMATION OF PROSTAGLANDINS PROSTACYCLINS,THROMBOXANES
• HYDROXY FATTY ACIDS –BETA HYDROXY BUTYRIC ACID –KETONE BODY—
ENERGY SOURCE IN STARVATION
• CHAULMOOGIC ACID ACID –CYCLIC FATTY ACID—CYCLO PENTENYL RING –
LEPROSY TREATMENT
• EICOSONOIDS –eg –PROSTAGLANDINS ,LEUKOTRIENES ,THROMBOXANES

14. DEFICIENCY MANIFESTIONS OF ESSENTIAL FATTY ACIDS
TOAD SKIN DISEASE ----PHRYNODERMA
POOR WOUND HEALING
HORNY ERUPTIONS ON POSTERIOR & LATERAL PARTS OF LIMB,ON BACK
,BUTTOCK

15. TOAD SKIN DISEASE---PHRYNODERMA

16. PROSTAGLANDINS
• CYCLIC COMPOUNDS (POLY ENOIC FATTY ACIDS )
• DERIVATIVES OF UNSATURATED FATTY ACIDS –ARACHIDONIC ACID
20C ,4 =BONDS –POSITIONS OF= BONDS --5,8,11,14

17. FUNCTIONS OF PROSTAGLANDINS
• PREVENT INFLAMMATION
• LOWER BLOOD PRESSURE
• TREATMENT OF GASRTIC ULCERS
• INHIBIT PLATELET AGGREGATION
• PROMOTE CLOTTING PROCESS
• TREATMENT OF ASTHMA & CONGENITAL HEART DISEASE

18. PROSTAGLANDINS SITE OF FORMATION FUNCTIONS
PGE2 MOST TISSUE VASODIALATATION
SMOOTH MUSCLE RELAXATION
LABOUR INDUCER –UTERINE
CONTRACTION
TREATMENT OF HYPER TENTION
PGF2ALPHA MOST TISSUE VASOCONSTRICTION
BRONCHOCONSTRICTION
SMOOTH MUSCLE CONTRACTION
MEDICAL TERMINATIONOF
PREGNANCY –UTERINE
CONTRACTION

19. PROSTAGLANDINS SITE OF FORMATION FUNCTIONS
PGI2 ENDOTHELIAL VESSELS VASODIALATATION
THROMBOXANES PLATELETS INCREASE PLATELET AGGREGATION
THROMBOSIS
VASO CONSTRICTIONS
MOBALIZATION OF
INTRACELLULAR CALCIUM
BRONCO CONSTICTION
LEUKOTRIENES
A4,B4.C4,D4,E4
LEUCOCYTES
PLATELETS
MAST CELLS
HEART CELLS
VASCULAR TISSUE
CHEMOTAXIS
MOVEMENT OF CELL RESPONSE
TO STIMULI
BRONCO CONSTICTION
VASO CONSTRICTIONS
C4,D4,E4—ALLERGIC
REACTIONS--FATAL

20. CHEMISTY OF CHOLESTEROL
• CHOLE =GREEK WORD ---MEANS BILE ,ISOLATED FROM BILE.SOLID
ALCOHOL FROM BILE ---ANIMAL STEROL
• MOLECULAR FORMULA C27H46O
• OH AT C3---AMPHILIC ,FORMS ESTER WITH FATTY ACIDS –
CHOLESTEROL ESTERS
• DOUBLE BOND BETWEEN C5= C6
• OCCURRENCE ---CELL MEMBRANE,BILE, LIPOPROTEINS

21. Cholesterol: is a sterol (with 8 carbons at C17,= bet 5&6)
Sterols: are steroids with 8-10 carbon atoms in the AMPHIPHATIC
side chain at C-17 & OH at C-3
•Cholesterol is the major sterol in animal tissues
•Plant sterols as B-sitosterol are poorly absorbed by
humans, it blocks the absorption of dietary cholesterol
•Dietary intake of plant steroid esters (trans fatty acid –free
margarine ) helps in reduction of plasma cholesterol

22. Structure of cholesterol and its ester.
Plant sterols block the absorption of dietary cholesterol.

24. FUNCTIONS OF CHOLESTEROL
• CELL MEMBRANE SRUCTURE FORMATION&FUNCTIONS
• LIPOPROTEIIN SYNTHESIS
• FATTY ACID TRANSPORT FOR BETA OXIDATION
• SYNTHESIS OF VITAMIN D
• SYNTHESIS OF STEROID HORMONES
• Glucocorticoid ---cortisol
• Minerocorticoid---Aldosterone
• Sex hormones----Progesterone//estradiol/Testosterone
• BILE SALTS SYNTHESIS
• POOR CONDUCTOR OF HEAT& ELECTICITY –INSULATING COVER—
BRAIN &MYELIN SHEATH

25. CHOLESTROL BIOSYNTHESIS
• Animal Sterol
• 70kg/body weight------2gm /kg -----140 gm cholesterol/70kg body weight
• Amphiphatic---hydrophilic& hydrophobic regions
• 1 gm/day synthesis
• Organs involved in synthesis---- Cytosol /microsomes of adrenal cortex
• Liver/intestine/testes/ovaries/skin/adrenal cortex

26. Synthesis of cholesterol
• SITES----CYTOSOL OF ALL TISSUES AND MICROSOMES
• REDUCING EUIVALENTS-----NADPH
• ENERGY---------ATP
• CARBON SKELETON------1,3,5,7,9,11,13,15,17,18,19,22,24,26

27. PROPERTIES OF CHOESTEROL
• YELLOWISH CRYSTALLINE SOLID
• MICROSCOPIC NOTCHED APPEARANCE
• INSOLUBLE IN WATER
• SOLUBLE IN CARBON TETRA CHLORIDE,CHLOROFORM,ETHERS
,BENZENE
• TEST FOR DETECTION ---ZAKS TEST –FERRIC CHLORIDE +H2SO4—
BROWN COLOR
•

28. CLINICAL SIGNIFICANCE OF CHOLESTEROL ESTIMATION
• Normal levels 150-200 mg/dl (adult )
• New born -----100 mg /dl
• Women < men ( Decrease in estrogen--------decrease cholesterol)
• ESTIMATION …….Liebermann Burchard reactions
• CHOLESTEROL + ACETIC UNHYDRIDE -------H2SO4 ---GREEN COMPLEX
• TOTAL CHOLESTROL = HDL+ LDL+VLDL
• TG /5= VLDL
• AFTER THE PPTATION OF LDL & VLDL BY PEG
• LDL CHOLESTEROL = Total cholesterol – ( HDL + VLDL)
• = Total cholesterol – ( HDL + TG/5)
• LDL CHOLESTEROL -----70-200 mg/dl
• HDL CHOLESTEROL -------30-60 mg/dl (increase in HDL cholesterol is
beneficial…..> /decrease in HDL harmful ….. CHD ------ATHEROSCLROSIS
• INCREASE IN CHOLESTROL ………CHD

29. CLINICAL SIGNIFICANCE OF CHOLESTEROL ESTIMATION
• HYPERCHOLESTEROLEMIA > 200 mg/dl
• Diabetes Mellitus ------increase availability of acetyl CoA
• Hypothyroid ( myxedema)…….decrease HDL receptors on
Hepatocytes
• Obstructive Jaundice -------obstruction in excretion of
cholesterol through bile
• Nephrotic syndrome----increase globulins -----increase in
plasmsa lipoproteins
• Hypercholesterolemia----atherosclerosis ----CHD -----
POSITIVE correlation of LDL--------NEGATIVE correlation HDL
•

30. CONTROL OF HYPERCHOLESTEROLEMIA
• PUFA –LCAT----CHOLESTEROL TRANSPORT ---EXCRETION OF CHOLE---
DECREASE IN CHOLESTEROL
• (PUFA---COTTON SEED OIL,SOYABEAN OIL,CORN OIL,FISH OIL,SUN
FLOWER OIL)
• (B) DIETARY FIBRES –DECREASE IN CHOLESTEROL ABSORPTION
• (C) AVOID CARBOHYDRATE DIET
• (D) DRUGS ---LOVASTATIN