LIPIDS IILIPIDS II

CLASSIFICATION OF FATTY ACIDS PRESENT AS GLYCERIDES IN FOOD FATS

 

I. Saturated Fatty Acids  

Butyric Butanoic CH3(CH2)2COOH butterfat

Caproic Hexanoic CH3(CH2)4COOH butterfat, coconut and palm nut oils

Caprylic Octanoic CH3(CH2)6COOH coconut and palm nut oils, butterfat

Capric Decanoic CH3(CH2)8COOH coconut and palm nut oils, butterfat

Lauric Dodecanoic CH3(CH2)10COOH coconut and palm nut oils, butterfat

Myristic Tetradecanoic CH3(CH2)12COOH coconut and Palm nut oil, most animal and plant fats

Palmitic Hexadecanoic CH3(CH2)14COOH practically all animal and plant fats

Stearic Octadecanoic CH3(CH2)16COOH animal fats and minor component of plant fats

Arachidic Eicosanoic CH3(CH2)18COOH peanut oil

Common Name

Systematic Name

Formula Common source

 Common Name

Systematic Name

Formula Common source

II. Unsaturated Fatty Acids  A. Monoethenoic Acids

 Oleic Cis 9-octadecenoic C17H33COOH plant and animal fats

Elaidic Trans 9-Octadecenoic C17H33COOH animal fats

B. Diethenoic Acids

Linoleic 9,12-Octadecadienoic C17H31COOH peanut, linseed, and cottonseed oils

C. Triethenoid Acids Linolenic 9,12,15-Octadecatrienoic C17H29COOH linseed and other seed

oilsEleostearic 9,11,13-Octadecatrienoic C17H29COOH peanut seed fats

D. Tetraethenoid AcidsMoroctic 4,8,12,15-Octadecatetraenoic C17H27COOH fish oils

Arachidonic 5,8,11,14-EicosatetraenoicC19H31COOH traces in animal fats

Common and Systematic Names of Fatty Common and Systematic Names of Fatty AcidsAcids  

Common Name

Systematic Name

Formula Common source 

A. Monoethenoic Acids 

Oleic Cis 9-octadecenoic C17H33COOH plant and animal fats

Elaidic Trans 9-Octadecenoic C17H33COOH animal fats

B. Diethenoic Acids

Linoleic 9,12-Octadecadienoic C17H31COOH peanut, linseed, and cottonseed oils

C. Triethenoid Acids Linolenic 9,12,15-Octadecatrienoic C17H29COOH linseed and other seed

oils

Eleostearic9,11,13-Octadecatrienoic C17H29COOH peanut seed fats

D. Tetraethenoid Acids

Moroctic 4,8,12,15-Octadecatetraenoic C17H27COOH fish oils

Arachidonic5,8,11,14-Eicosatetraenoic C19H31COOH traces in animal fats

Biomedical importance of fatty acids:Biomedical importance of fatty acids: Human body can synthesize various fatty acids Human body can synthesize various fatty acids

with the exception of;with the exception of;

““linoleiclinoleic”” and and ““linoleniclinolenic”” acids; this is because acids; this is because body tissues cannot introduce double bonds body tissues cannot introduce double bonds beyond the beyond the ΔΔ 9 position. 9 position.

In contrast, plants are able to introduce double In contrast, plants are able to introduce double

bonds at the bonds at the ΔΔ 12 and 12 and ΔΔ 15 positions. 15 positions.

Therefore, linoleic acid and linolenic acid are Therefore, linoleic acid and linolenic acid are considered as nutritionally essential fatty acids,considered as nutritionally essential fatty acids,

and must be supplied in a diet of plant origin or and must be supplied in a diet of plant origin or from animals that have consumed these plant from animals that have consumed these plant fats.fats.

1. Dietary 1. Dietary ώώ -3 fatty acids (in fish oil and plant -3 fatty acids (in fish oil and plant fats)fats)

can reduce serum triglycerides, thrombosis andcan reduce serum triglycerides, thrombosis and the risk of cardiovascular mortality. the risk of cardiovascular mortality.

2- 2- ώώ -6 fatty acids (in olive oil and corn oil) -6 fatty acids (in olive oil and corn oil)

lower plasma cholesterol and protect against lower plasma cholesterol and protect against coronary heart disease.coronary heart disease.

3-Generally, a high ratio of polyunsaturated fatty3-Generally, a high ratio of polyunsaturated fatty

acids to saturated fatty acids in the diet is a acids to saturated fatty acids in the diet is a major factor to prevent coronary heart disease.major factor to prevent coronary heart disease.

Eicosanoids: Eicosanoids: Prostaglandins, Prostaglandins, Leukotrienes, and Leukotrienes, and

ThromboxanesThromboxanes Fatty acids which canFatty acids which can’’t be synthesized by t be synthesized by

the body are the body are essential fatty acidsessential fatty acids– Linoleic acid Linoleic acid is an essential fatty acid required is an essential fatty acid required

to make arachadonic acidto make arachadonic acid Arachidonic acid (20 C) is the eicosanoid Arachidonic acid (20 C) is the eicosanoid

precursorprecursor Eicosanoids are three groups of structurally Eicosanoids are three groups of structurally

related compoundsrelated compounds– Prostaglandins Prostaglandins – LeukotrienesLeukotrienes– ThromboxanesThromboxanes

COO-

arachadonic acid

ProstaglandinsProstaglandins Potent biological moleculesPotent biological molecules They act like hormones in controlling the They act like hormones in controlling the

bodybody’’s processes s processes StructureStructure

– Synthesized from 20-carbon unsaturated fatty Synthesized from 20-carbon unsaturated fatty acidsacids

– Cyclic compounds including a 5-carbon ring Cyclic compounds including a 5-carbon ring Names are based on ring substituents and Names are based on ring substituents and

number of side-chain double bondsnumber of side-chain double bonds Made in most tissuesMade in most tissues

– Exert their effects on cells that produce them Exert their effects on cells that produce them and cells in the immediate vicinityand cells in the immediate vicinity

Biological Processes Biological Processes Regulated by EicosanoidsRegulated by Eicosanoids

1.1. Blood clottingBlood clotting– Thromboxane AThromboxane A22 stimulates constriction stimulates constriction

of blood vessels and platelet aggregationof blood vessels and platelet aggregation– Prostacyclin dilates blood vessels and Prostacyclin dilates blood vessels and

inhibits platelet aggregationinhibits platelet aggregation

2.2. Inflammatory responseInflammatory response– Prostaglandins mediate aspects of Prostaglandins mediate aspects of

inflammatory responseinflammatory response

3.3. Reproductive systemReproductive system– Stimulation of smooth muscle by PGEStimulation of smooth muscle by PGE22

Biological Processes Biological Processes Regulated by EicosanoidsRegulated by Eicosanoids

4.4. Gastrointestinal tractGastrointestinal tract– Prostaglandins inhibit gastric secretionProstaglandins inhibit gastric secretion– Inhibition of hormone-sensitive lipasesInhibition of hormone-sensitive lipases– Prostaglandins increase secretion of protective Prostaglandins increase secretion of protective

mucusmucus

5.5. KidneysKidneys– Prostaglandins dilate renal blood vesselsProstaglandins dilate renal blood vessels– Results in increased water and electrolyte Results in increased water and electrolyte

excretionexcretion

6.6. Respiratory tractRespiratory tract– Leukotrienes promote the constriction of bronchiLeukotrienes promote the constriction of bronchi– Prostaglandins promote bronchodilationProstaglandins promote bronchodilation

Structures of Four Structures of Four ProstaglandinsProstaglandins

Aspirin and ProstaglandinsAspirin and ProstaglandinsAspirin inhibits prostaglandin synthesis by Aspirin inhibits prostaglandin synthesis by acetylating cyclooxygenase, an enzyme acetylating cyclooxygenase, an enzyme necessary for prostaglandin synthesisnecessary for prostaglandin synthesis

Overview of Prostaglandin Overview of Prostaglandin Synthesis From Arachidonic Synthesis From Arachidonic

AcidAcid

Test your understandingTest your understanding1- Fatty acids are1- Fatty acids are

A.A. Soluble in waterSoluble in water

B.B. Esters of long chain alcoholEsters of long chain alcohol

C.C. Saturated hydrocarbonsSaturated hydrocarbons

D.D. Long chain carboxylic acidsLong chain carboxylic acids

E.E. None of the aboveNone of the above

2- Saturated fatty acids are those:A.Containing no carbon carbon double bonds.

B.Contain carbon carbon double bond.C.Mainly solid at room temperature.

D.Both b and c.E.Both a and c.

3- Unsaturated fatty acids are those:A.Containing no carbon carbon double bonds.

B.Contain carbon carbon double bond.C.Liquid at room temperature.

D.Both b and c.E.Mainly solid at room temperature.

Test your understandingTest your understanding

Test your understandingTest your understanding

4- Arachidonic acid is a:4- Arachidonic acid is a:

A.A. 20:1 20:1 ΔΔ 5 fatty acid 5 fatty acid

B.B. 20:2 20:2 ΔΔ 5,14 fatty acid 5,14 fatty acid

C.C. 20:3 20:3 ΔΔ 5,8,11,14 fatty acid 5,8,11,14 fatty acid

D.D.20:4 20:4 ΔΔ 5,8,11,14 fatty acid 5,8,11,14 fatty acid

E.E. 20:5 20:5 ΔΔ 5 fatty acid 5 fatty acid

COO-

arachadonic acid

5- 5- Linoleic acid is a polyunsaturated fatty acids, that Linoleic acid is a polyunsaturated fatty acids, that means:means:

It has no double bondIt has no double bond It is solid at room temperatureIt is solid at room temperature It has one double bondIt has one double bond It is nonessential fatty acidIt is nonessential fatty acid It is liquid at room temperatureIt is liquid at room temperature

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6- 6- Regarding prostaglandins all of the following is Regarding prostaglandins all of the following is true except:true except:

A.A. Synthesized from arachidonic acidSynthesized from arachidonic acid

B.B. Increase secretion of gastric protective mucusIncrease secretion of gastric protective mucus

C.C. Dilate renal blood vesselsDilate renal blood vessels

D.D. Stimulate platelets aggregation Stimulate platelets aggregation

E.E. Mediate aspects of inflammatory responseMediate aspects of inflammatory response

Test your understandingTest your understanding