Lipid Chemistry Lecture Notes - Sinai University

Dr. Mohamed Elsafty Lecturer of Biochemistry Faculty of Dentistry sinaiuniversity.net  ‫رؤية الكلية‪:‬‬ ‫تتطلع الكلية أن تكون رائدة في مجال طب الفم واألسنان من خالل التميز في التعليم والبحث‬ ‫العلمي وخدمة المجتمع محليا ً وإقليميا ً ود...

Dr. Mohamed Elsafty Lecturer of Biochemistry Faculty of Dentistry sinaiuniversity.net  ‫رؤية الكلية‪:‬‬ ‫تتطلع الكلية أن تكون رائدة في مجال طب الفم واألسنان من خالل التميز في التعليم والبحث‬ ‫العلمي وخدمة المجتمع محليا ً وإقليميا ً ودوليا ً‪.‬‬ ‫‪[email protected]‬‬ ‫‪[email protected]‬‬ ‫‪www.su.edu.eg‬‬  ‫رسالة الكلية‪:‬‬ ‫تلتزم كلية طب األسنان بجامعة سيناء‪ -‬فرع العريش بإعداد خريجين مؤهلين طبقا ً للمعاييرالقومية‬ ‫األكاديمية المرجعية‪ ،‬قادرين على المنافسة في سوق العمل المحلي واإلقليمى وإجراء البحوث العلمية‬ ‫وتقديم الخدمات المجتمعية في إطار اإللتزام بأخالقيات المهنة‪.‬‬ ‫‪[email protected]‬‬ ‫‪[email protected]‬‬ ‫‪www.su.edu.eg‬‬  Lipid Chemistry Lecture 1 28 slides INDEX [email protected] [email protected] www.su.edu.eg  Lecture aim Develop the student basic knowledge about definitions, importance, chemical structure and classification of lipids. [email protected] [email protected] www.su.edu.eg  Lecture Objectives Illustrate Lipids, Dietary sources and biological importance. Classify lipids according to their structure. Discuss the fatty acid structure, types and numbering. Explain types of double bond, and trans fats. Explicate glycerol, properties and medical uses. List simple lipids and its types. Explain triacylglycerol, dietary source, body distribution and types. [email protected] [email protected] www.su.edu.eg  Lipids Lipids are organic compounds insoluble in water due to hydrocarbon chains, but soluble in fat PICTURE HERE solvents such as ether, chloroform. [email protected] [email protected] www.su.edu.eg Dietary sources: Lipids are widely distributed in both animal and plants. Animal source: fats, butter, egg yolk, cream, liver and PICTURE HERE brain. Plant source: nuts, peanuts, olive, olive oil, cotton seed oil, sunflower oil and linseed oil. [email protected] [email protected] www.su.edu.eg  Biological importance of lipids I) In diet: Source of high energy supply 20-25% of the caloric requirements, (1gm lipids gives 9,3 Kcal) Play an important role by helping the absorption of fat-soluble vitamins (A,D,E,K) Contain essential fatty acids which maintains normal growth. Make diet palatable. [email protected] [email protected] www.su.edu.eg II) In the body: Present in adipose tissues serves as storage form of energy. Serves as thermal insulator in the subcutaneous tissues. Non-polar lipids act as electrical insulator, allowing rapid propagation of depolarization waves along myelinated PICTURE HERE nerves. Enter in the structure of Nervous system , Cell membrane and steroid hormones. [email protected] [email protected] www.su.edu.eg  Classification of lipids Lipids Derived lipids Simple lipids Compound or conjugated lipids Fatty acids, alcohols (Esters of fatty acids with Glycerol, Various alcohols) sterols Fats and Waxes Phospholipids Glycolipids sulpholipids Lipoproteins Oils (esters of fatty (Esters Acids with long chain of fatty acid Aliphatic alcohols And glycerol Gangliosides Cerbrosides Phosphatidic Lecithins Cephalins Plasmalogens Sphingomyelins acids 11  1- Simple lipids: Esters of fatty acids with various alcohol. a. Neutral fats: Ester of fatty acids with glycerol. PICTURE HERE b. Waxes: Esters of fatty acids with long chain alcohol. [email protected] [email protected] www.su.edu.eg  2- Compound or conjugated lipids: Esters of fatty acids with alcohol in addition to non lipid part: PICTURE HERE a. Phospholipids: Lipids + phosphoric acid. b. Glycolipids: Lipids + carbohydrates. c. Sulpholipids: Lipids + Sulfur. d. Lipoproteins: Lipids + Protein. [email protected] [email protected] www.su.edu.eg  3- Derived lipids: These include substances given by hydrolysis of simple & compound lipids, e.g. fatty acids, glycerol, or substances which soluble in water as Steroids ketone bodies carotenoids. [email protected] [email protected] www.su.edu.eg  Fatty acids These are organic monocarboxylic acids with long aliphatic non branched chain (hydrocarbon). PICTURE HERE Obtained by hydrolysis of neutral fats (triglycerides). Occur mainly as ester in fat & oil, or free F.A in the plasma. Occur in natural fat contain even number. [email protected] [email protected] www.su.edu.eg Fatty acids are classified according to the presence or absence of double bonds into: 1- Saturated fatty acids: contain no double bonds. 2- Unsaturated fatty acids: contain double bonds. [email protected] [email protected] www.su.edu.eg  Saturated fatty acids (-anoic): CH3-(CH2 )n-COOH Have no double bonds in the chain. According to the number of carbon atoms ,there are two types: 1- Short chain fatty acids: contain from 2-10 carbons. Acetic acid C2: CH3-COOH Propionic acid C3: CH3-CH2-COOH Butyric acid C4: CH3-CH2-CH2-COOH. 2- Long chain fatty acids: contain more than 10 carbon atoms. Palmitic acid C16: CH3-(CH2)14-COOH. Stearic acid C18: CH3-(CH2)16-COOH [email protected] [email protected] www.su.edu.eg  Numbering of carbon atoms A. Alpha numbering Δ: B. The COOH is considered as carbon number 1 and the numbering is started from it. Palmitoleic acid is called 16:1 Δ 9 CH3-(CH2)5-CH=CH-(CH2)7-COOH PICTURE HERE B. Omega numbering W: The CH3 is considered as the first carbon and the numbering is started from it. CH3-(CH2)5-CH=CH-(CH2)7-COOH Palmitoleic acid is called 16:1 W 7 [email protected] [email protected] www.su.edu.eg Unsaturated fatty acids: (-enoic): Cn-H2n-1-COOH. Contain double bond. A- According to the number of double bonds unsaturated F.A. are classified into: 1- Monounsaturated fatty acids: It contain one double bonds and are called monoenoic. Examples : Palmitoleic acid: C16:1Δ9 or (W 7 ) CH3-(CH2)5-CH=CH-(CH2)7-COOH Oleic acid: C18:1Δ9 or (W9 ) CH3-(CH2)7-CH=CH-(CH2)7-COOH [email protected] [email protected] www.su.edu.eg 2- Polyunsaturated fatty acids: Contain more than one double bonds and are called polyenoic Examples: Linoleic acid: 18: 2 Δ9,12 or W-6 CH3-(CH2)4-CH=CH-CH2-CH=CH-(CH2)7-COOH Arachidonic acid : 20: 4 Δ5,8,11,14 or W -6 Linolenic acid : 18: 3 Δ9,12,15 or W-3 Eicosapentaenoic acid (EPA): 20: 5 Δ5,8,11,14.17 W-3 Docosahexaenoic acid (DHA): 22: 6 Δ4,7,10,13,16,19 W-3 [email protected] [email protected] www.su.edu.eg B. According to the position of double bonds: 1. W- 3 fatty acids: The first double bond is on w-3 carbon. It include linolenic acid, Eicosapentaenoic acid and docosahexaenoic acid. 2. W- 6 fatty acids: The first double bonds is on w-6 carbons. It include; linoleic acid and arachidonic acid. [email protected] [email protected] www.su.edu.eg C. According to the nutritional value: 1- Essential fatty acids: They cannot be synthesized inside the body and must be taken in diet e.g. linoleic acid and linolenic acid. 2- Non-essential fatty acids: They can be synthesized inside the body. The human body has the enzyme system that can form one double bond at C9, Δ9 [email protected] [email protected] www.su.edu.eg Types of double bonds: Most naturally occurring fatty acids have cis double bonds. PICTURE HERE Trans fatty acids are by-product of hydrogenation of plant oils. [email protected] [email protected] www.su.edu.eg  Trans-fats: Fats which contain trans fatty acids. Not present in the nature but they are the by- product of hydrogenation of vegetable oils (margarine). PICTURE HERE Trans fats have comparable effects in promotion of hypercholesterolemia, atherosclerosis, ischemic heart diseases, and cancer. [email protected] [email protected] www.su.edu.eg  Importance of polyunsaturated fatty acids Formation of phospholipids. Enter in the structure of cell membrane. Esterification of cholesterol. Arachidonic acid is the precursor of prostanoids. Essential for normal growth. Anti-atherogenic properties protecting the body against atherosclerosis and ischemic heart diseases. [email protected] [email protected] www.su.edu.eg New research shows that dietary intake of polyunsaturated fatty acids like fish oil, which is known to have anti-inflammatory properties, shows promise for the treatment and prevention PICTURE HERE of periodontitis is a common inflammatory disease in which gum tissue separates from teeth—leading to accumulation of bacteria and potential bone and tooth loss. [email protected] [email protected] www.su.edu.eg  Alcohols Alcohols associated with lipids include glycerol, cholesterol & long chain alcohol (cetyl alcohol (C16) in wax. Glycerol: polyhydric alcohol contains PICTURE HERE 3carbon atoms 3 OH 3 sites for esterification [email protected] [email protected] www.su.edu.eg  Properties of glycerol Water soluble. Insoluble in fat solvent. Sweet taste. PICTURE HERE - On esterification with fatty acids: Monoacylglycerol: Glycerol + one fatty acid. Diacylglycerol: Glycerol + two fatty acid. Triacylglycerol: Glycerol + three fatty acids. [email protected] [email protected] www.su.edu.eg  Medical uses of glycerol Nitroglycerine is vasodilator to coronary arteries. PICTURE HERE Enter in the manufacture of skin moisturizer. Rectally, glycerol is used as laxative. [email protected] [email protected] www.su.edu.eg  Simple lipids: Esters of fatty acids with various alcohol. a. Neutral fats: Ester of fatty acids with PICTURE HERE glycerol. b. Waxes: Esters of fatty acids with long chain alcohol. [email protected] [email protected] www.su.edu.eg Neutral fats (Triacylglycerol ): They are called neutral fats because they carry no charge. PICTURE HERE Glycerol is esterified with 3 fatty acids. [email protected] [email protected] www.su.edu.eg  Dietary sources of triacylglycerols (TAGs): Animal sources: butter , cream, animal fats. PICTURE HERE Plant sources: cotton seed oil, palm oil. Marine sources: fish liver oil. [email protected] [email protected] www.su.edu.eg Body triacylglycerol: Location: adipose tissue, under skin, around important organs, omentum and mesentery. Sources: excess carbohydrates and dietary lipids. PICTURE HERE Human fat is liquid at room temp. and contain high content of oleic acid C18: 1. Functions: Heat insulator. Stored energy. Fixation and protection of important organs. [email protected] [email protected] www.su.edu.eg Types of triacylglycerols: Simple TAGs: glycerol + 3 similar fatty acids e.g. tripalmitin & triolein. PICTURE HERE Mixed TAGs: glycerol + 3 different fatty acids e.g. 1, 2 distrearinpalmitin & oleopalmitostearin. [email protected] [email protected] www.su.edu.eg  References - Kennelly PJ, Botham KM, McGUINNESS O, Rodwell VW, Weil P. Harper's Illustrated Biochemistry, 32nd edition. New York, NY. McGraw Hill; 2023. - Champe PC, Harvey RA, Ferrier DR, Lippincott William & Wilkins. Lippincott Reviews of Biochemistry, London, 7th edition; 2017. [email protected] [email protected] www.su.edu.eg  THANK YOU For any questions feel free to contact me by mail [email protected] 01147996609 Dr. Mohamed Elsafty Lecturer of Biochemistry Faculty of Dentistry