1. LIPIDS II

2. CLASSIFICATION OF FATTY ACIDS PRESENT AS GLYCERIDES IN FOOD FATS I. Saturated Fatty Acids Butyric ButanoicCH 3 (CH 2 ) 2 COOHbutterfat CaproicHexanoic CH 3 (CH 2 ) 4 COOH butterfat, coconut and palm nut oils CaprylicOctanoic CH 3 (CH 2 ) 6 COOHcoconut and palm nut oils, butterfat Capric DecanoicCH 3 (CH 2 ) 8 COOH coconut and palm nut oils, butterfat LauricDodecanoicCH 3 (CH 2 ) 10 COOHcoconut and palm nut oils, butterfat Myristic Tetradecanoic CH 3 (CH 2 ) 12 COOH coconut and Palm nut oil, most animal and plant fats PalmiticHexadecanoicCH 3 (CH 2 ) 14 COOHpractically all animal and plant fats Stearic Octadecanoic CH 3 (CH 2 ) 16 COOHanimal fats and minor component of plant fats ArachidicEicosanoicCH 3 (CH 2 ) 18 COOH peanut oil Common Name Systematic Name FormulaCommon source

3. Common Name Systematic Name FormulaCommon source II. Unsaturated Fatty Acids A. Monoethenoic Acids OleicCis 9-octadecenoic C 17 H 33 COOHplant and animal fats ElaidicTrans 9-Octadecenoic C 17 H 33 COOHanimal fats B. Diethenoic Acids Linoleic9,12-OctadecadienoicC 17 H 31 COOH peanut, linseed, and cottonseed oils C. Triethenoid Acids Linolenic 9,12,15-OctadecatrienoicC 17 H 29 COOHlinseed and other seed oils Eleostearic 9,11,13-OctadecatrienoicC 17 H 29 COOHpeanut seed fats D. Tetraethenoid Acids Moroctic4,8,12,15-OctadecatetraenoicC 17 H 27 COOH fish oils Arachidonic5,8,11,14-EicosatetraenoicC 19 H 31 COOHtraces in animal fats

4. Common and Systematic Names of Fatty Acids Common Name Systematic Name FormulaCommon source A. Monoethenoic Acids Oleic Cis 9-octadecenoicC 17 H 33 COOHplant and animal fats Elaidic Trans 9-Octadecenoic C 17 H 33 COOHanimal fats B. Diethenoic Acids Linoleic 9,12-Octadecadienoic C 17 H 31 COOHpeanut, linseed, and cottonseed oils C. Triethenoid Acids Linolenic9,12,15-Octadecatrienoic C 17 H 29 COOHlinseed and other seed oils Eleostearic 9,11,13-OctadecatrienoicC 17 H 29 COOHpeanut seed fats D. Tetraethenoid Acids Moroctic4,8,12,15-Octadecatetraenoic C 17 H 27 COOHfish oils Arachidonic5,8,11,14-Eicosatetraenoic C 19 H 31 COOHtraces in animal fats

5. Biomedical importance of fatty acids: Biomedical importance of fatty acids: Human body can synthesize various fatty acids with the exception of; Human body can synthesize various fatty acids with the exception of; “ linoleic ” and “ linolenic ” acids; this is because body tissues cannot introduce double bonds beyond the Δ 9 position. “ linoleic ” and “ linolenic ” acids; this is because body tissues cannot introduce double bonds beyond the Δ 9 position. In contrast, plants are able to introduce double bonds at the Δ 12 and Δ 15 positions. In contrast, plants are able to introduce double bonds at the Δ 12 and Δ 15 positions. Therefore, linoleic acid and linolenic acid are considered as nutritionally essential fatty acids, Therefore, linoleic acid and linolenic acid are considered as nutritionally essential fatty acids, and must be supplied in a diet of plant origin or from animals that have consumed these plant fats. and must be supplied in a diet of plant origin or from animals that have consumed these plant fats.

6. 1. Dietary ώ -3 fatty acids (in fish oil and plant fats) can reduce serum triglycerides, thrombosis and can reduce serum triglycerides, thrombosis and the risk of cardiovascular mortality. the risk of cardiovascular mortality. 2- ώ -6 fatty acids (in olive oil and corn oil) lower plasma cholesterol and protect against coronary heart disease. lower plasma cholesterol and protect against coronary heart disease. 3-Generally, a high ratio of polyunsaturated fatty acids to saturated fatty acids in the diet is a major factor to prevent coronary heart disease. acids to saturated fatty acids in the diet is a major factor to prevent coronary heart disease.

7. Eicosanoids: Prostaglandins, Leukotrienes, and Thromboxanes Fatty acids which can ’ t be synthesized by the body are essential fatty acids Fatty acids which can ’ t be synthesized by the body are essential fatty acids –Linoleic acid is an essential fatty acid required to make arachadonic acid Arachidonic acid (20 C) is the eicosanoid precursor Arachidonic acid (20 C) is the eicosanoid precursor Eicosanoids are three groups of structurally related compounds Eicosanoids are three groups of structurally related compounds –Prostaglandins –Leukotrienes –Thromboxanes

8. Prostaglandins Potent biological molecules Potent biological molecules They act like hormones in controlling the body ’ s processes They act like hormones in controlling the body ’ s processes Structure Structure –Synthesized from 20-carbon unsaturated fatty acids –Cyclic compounds including a 5-carbon ring Names are based on ring substituents and number of side-chain double bonds Names are based on ring substituents and number of side-chain double bonds Made in most tissues Made in most tissues –Exert their effects on cells that produce them and cells in the immediate vicinity

9. Biological Processes Regulated by Eicosanoids 1. Blood clotting –Thromboxane A 2 stimulates constriction of blood vessels and platelet aggregation –Prostacyclin dilates blood vessels and inhibits platelet aggregation 2. Inflammatory response –Prostaglandins mediate aspects of inflammatory response 3. Reproductive system –Stimulation of smooth muscle by PGE 2

10. Biological Processes Regulated by Eicosanoids 4. Gastrointestinal tract –Prostaglandins inhibit gastric secretion –Inhibition of hormone-sensitive lipases –Prostaglandins increase secretion of protective mucus 5. Kidneys –Prostaglandins dilate renal blood vessels –Results in increased water and electrolyte excretion 6. Respiratory tract –Leukotrienes promote the constriction of bronchi –Prostaglandins promote bronchodilation

11. Structures of Four Prostaglandins

12. Aspirin and Prostaglandins Aspirin inhibits prostaglandin synthesis by acetylating cyclooxygenase, an enzyme necessary for prostaglandin synthesis

13. Overview of Prostaglandin Synthesis From Arachidonic Acid

14. Test your understanding 1- Fatty acids are A. Soluble in water B. Esters of long chain alcohol C. Saturated hydrocarbons D. Long chain carboxylic acids E. None of the above

15. 2- Saturated fatty acids are those: A. A.Containing no carbon carbon double bonds. B. B.Contain carbon carbon double bond. C. C.Mainly solid at room temperature. D. D.Both b and c. E. E.Both a and c. 3- Unsaturated fatty acids are those: A. A.Containing no carbon carbon double bonds. B. B.Contain carbon carbon double bond. C. C.Liquid at room temperature. D. D.Both b and c. E. E.Mainly solid at room temperature. Test your understanding

16. 4- Arachidonic acid is a: A. 20:1 Δ 5 fatty acid B. 20:2 Δ 5,14 fatty acid C. 20:3 Δ 5,8,11,14 fatty acid D. 20:4 Δ 5,8,11,14 fatty acid E. 20:5 Δ 5 fatty acid

17. 5- Linoleic acid is a polyunsaturated fatty acids, that means: It has no double bond It has no double bond It is solid at room temperature It is solid at room temperature It has one double bond It has one double bond It is nonessential fatty acid It is nonessential fatty acid It is liquid at room temperature It is liquid at room temperature Test your understanding

18. 6- Regarding prostaglandins all of the following is true except: A. Synthesized from arachidonic acid B. Increase secretion of gastric protective mucus C. Dilate renal blood vessels D. Stimulate platelets aggregation E. Mediate aspects of inflammatory response Test your understanding