Lipid Chemistry 2024 PDF

LIPID CHEMISTRY Learning Objectives At the end of the lessons, the learners should be able to: Classify lipids. Discuss properties of fats and oil. Compare saturated from unsaturated fatty acids; omega=3-fatty acids from omega-6 fatty acids. Name fats and oil using IUPAC system. Des...

LIPID CHEMISTRY Learning Objectives At the end of the lessons, the learners should be able to: Classify lipids. Discuss properties of fats and oil. Compare saturated from unsaturated fatty acids; omega=3-fatty acids from omega-6 fatty acids. Name fats and oil using IUPAC system. Describe structure of cholesterol and identify cholesterol derivatives and its biological functions. Appreciate the importance of lipids especially the brain and membrane lipids in the living cell. Identify messenger lipids, its precursor, pathway and functions. Discuss structure of fat-soluble vitamins, chemical name and functions. Thoughts to ponder  LIPIDS Are important constituents of protoplasm, characterized by being insoluble in water but soluble in ether, chloroform and other fat solvents. C, H, O containing organic molecule Some have phosphorous, and nitrogen The brain and nervous tissues are rich in certain lipids  Functions of Lipids Provide a major way of storing chemical energy and carbon atoms in the body. Surround and insulate vital body organs, providing protection from mechanical shock and preventing excessive heat lost. Phospholipids, glycolipids and cholesterol are the basic components of cell membranes. Several cholesterol derivatives function as chemical messengers (hormones) w/in the body. Five Categories of Lipids on the Basis of Lipid Function 1. Energy-storage lipids (triacylglycerols) 2. Membrane lipids (phospholipids, sphingoglycolipids, and cholesterol) 3. Emulsification lipids (bile acids) 4. Messenger lipids (steroid hormones and eicosanoids) 5. Protective-coating lipids (biological waxes) Classification of Lipids I. SIMPLE LIPIDS – esters of fatty acids and alcohol. A. Glycerides – esters of fatty acids & glycerol 1. FATS solid at room temperature contain greater % of saturated long chain fatty acid, FA High melting point 2. OIL  liquid at room temperature  contain greater % of unsaturated fatty acid, FA  Low melting point B. Waxes - esters of long chain fatty acids and long chain monohydric alcohols or sterols. FATTY ACIDS  FATTY ACIDS Naturally occurring monocarboxylic acid. Because of the pathway they are synthesized, fatty acids contain an even number of carbon atoms and have a carbon chain that is unbranched. C4 to C6 = short-chain FAs C8 to C10 = medium-chain FAs  FATTY ACIDS A. SATURATED FATTY ACIDS – is a fatty acid w/ a carbon chain in w/c all C to C bonds are single bonds. B. UNSATURATED FATTY ACIDS 1. Monounsaturated FAs (MUFA) – is a FA w/ a carbon chain in w/c one carbon-carbon double bond is present. (MUFA) Abundant in peanuts & peanut oil, canola oil, olive oil, avocado 2. Polyunsaturated Fas(PUFA) – is a FA w/ a carbon chain in w/c two or more carbon-carbon double bonds are present.  Saturated Fatty Acids Mainly found in animal fats like butter, beef tallow, lard, meats, bacon and sausages, dairy fats, organ meats, milk and milk products, egg yolk. Coconut oil is saturated fat but of medium- chain length unlike most saturated fats. TRANS-FAT – present naturally in meat and dairy products in small amount. Most trans fat are found in hard margarine, shortening and foods made w/ these ingredients as cookies, breads, and pastries, fried food products such as snack chips. https://andieholman.com/dangers-of-transfats  I. The SATURATED Fatty Acids Found in Lipids Name Formula Structural Notation Occurrence butyric C3H7COOH 4:0 butter caproic C5H11COOH 6:0 butter caprylic C7H15COOH 8:0 coconut capric C9H19COOH 10:0 palm nut lauric C11H23COOH 12:0 laurel, coconut oil myristic C13H27COOH 14:0 nutmeg palmitic C15H31COOH 16:0 palm oil & lard stearic C17H35COOH 18:0 tallow arachidic C19H39COOH 20:0 peanut cerotic C25H51COOH 26:0 waxes  II. The UNSATURATED Fatty Acids Found in Lipids Name Formula Structural Notation Occurrence Monounsaturated (MUFA) Oleic acid C17H33COOH 18:1 ∆9 olive oil Polyunsaturated (PUFA) Linoleic C17H31COOH 18:2 ∆9,12 corn oil Linolenic C17H29COOH 18:3 ∆9,12,15 linseed oil Arachidonic C19H31COOH 20:4 ∆5,8,11,14 lecithin & cephalin Clupanodonic C21H33COOH 22:5 ∆3,6,9,12,15 fish oils EPA (eicosapentaenoic acid) 20:5 ∆5,8,111,14,17 DHA (docosahexaenoic acid) 22:6 ∆4,7,10,13,16,19 EXERCISE 1- DRAW THE CONDENSED STRUCTURAL FORMULAS and LINE ANGLE FORMULAS OF THE FOLLOWING FATTY ACIDS: Example: Butanoic acid C3H7COOH 5:0 Condensed structural Line angle formula formula 1. Stearic acid 18:0 7. capric acid 10:0 2. Linoleic acid 18:2 8. DHA 22:6 3. Oleic acid 18:1 9. arachidic acid 20:0 4. Arachidonic acid 20:4 10. caproic acid 6:0 5. EPA 20:5 6. Palmitic acid 16:0 III. HYDROXY ACIDS Ricinoleic C17H32(OH)COOH castor oil Cerebronic C23H46(OH)COOH phrenosin Dihydroxystearic C17H33(OH)2COOH castor oil IV. CYCLIC ACIDS Hydnocarpic C15H27COOH chaulmoogra oil Chaulmogric C17H31COOH chaulmoogra oil EXERCISE 2 A. Quantify the following: ____1. H atoms in linoleic acid ____4. no. of double bonds in the hydro- ____2. C atoms in caprylic acid carbon chain of arachidonic acid ____3. O atoms in myristic acid ____5. H atoms in the hydrocarbon chain of stearic acid B. Classify the following fatty acids by writing: A – if saturated B –if MUFA C –if PUFA D – if hydroxy FA E – if cyclic FA ____1. cerebronic ____5. C17H29COOH ___9. clupanodonic ____2. cerotic ___6. C17H35COOH ___10. omega-6 ____3. lauric ____7. C15H31COOH  How are fats and oil formed? Formed from esterification reaction, a kind of condensation reaction. Fats and oil are called triacylglycerol or triglycerides. When do you say the triglyceride is a fat or oil? FAT- all R groups are saturated FAs or more saturated than unsaturated FAs OIL – all R groups are unsaturated FAs or more unsaturated than saturated FAs OMEGA-3 Fatty Acids - lowers plasma triglyceride level Sources: fish & fish oil (fresh tuna, salmon, etc…), soybean, canola oil, seaweeds, nuts ***lowers plasma triglyceride level Omega-6 Fatty Acids – reduces risk of heart disease, lowers bad cholesterol and raises good cholesterol levels. Sources: vegetable oils, nuts, seeds, grains Why are they called omega-3 and omega-6 fatty acids? Omega, (ω), is the 24th and final letter in the Greek alphabet. The omega numbers refer to how many carbons away from the methyl end of the fatty acid chain that the first carbon- carbon double bond appears. The last carbon in the hydrocarbon chain is an omega carbon. If the double bond is three carbons away, it’s called an omega-3 fatty acid. If it’s six carbons away, it’s called an omega-6 fatty acid.  OMEGA-3-FATTY ACIDS Linolenic acid : C17H29COOH 18:3 ∆9,12,15 Flax seeds produce linseed oil , which has a very high ALA content (alpha- linolenic acid). Other sources: walnuts, canola, soybeans oil  EPA and DHA Are important constituents of the communication membranes of the brain. Reduces heart disease risk Lowers blood pressure and supports circulation Are necessary for normal brain development Are active in the retina of the eye Are precursors of natural anti-inflammatory substances called prostaglandins and leukotrienes  OMEGA-3-FATTY ACIDS EPA – Eicosapentaenoic acid C19H29COOH 20:5 ∆5,8,11,14,17 Omega-3 is easily damaged by oxygen, light and heat, which means that eating the foods that contain them raw is best -- though baking or broiling will cause less nutrient loss than frying or boiling.  OMEGA-3-FATTY ACIDS DHA – (docosahexaenoic acid) C21H31COOH 22:6 ∆4,7,10,13,16,19  OMEGA-6-FATTY ACIDS Arachidonic Acid C19H31COOH 20:4 ∆ 5,8,11,14 Arachidonic acid in the human body usually comes from dietary animal sources—meat, eggs, dairy—or is synthesized from linoleic acid.  Omega -3 and Omega-6 Fatty Acids Are used to make hormone-like compounds called eicosanoids. Eicosanoids help regulate bodily functions such as: blood clotting, immune function, and blood pressure control.  BIOLOGICAL WAX is a monoester of a long chain fatty acid and a long chain alcohol. FATTY acids in waxes are saturated. (14 to 36 carbon atoms) ALCOHOLS may be saturated or unsaturated and may contain from 16 to 30 carbon atoms. Examples: Carnauba wax , bees wax, lanolin Human ear wax is not a true biological wax – it is a mixture of triacylglycerols, phospholipids, esters of cholesterol. Paraffin waxes are mineral waxes – a mixture of long chain alkanes. (candles, waterproof coating for paper products)  Chemical Reactions of Triglycerides 1. Hydrolysis – reverse of esterification reaction. Addition of water, acid or enzyme (lipase) Products: glycerol + fatty acid Tripalmitin Glycerol Palmitic Acid Chemical Reactions of Triglycerides 2. Saponification – the formation of salt or soap with with alkali like NaOH or KOH. (Alkaline hydrolysis) Products – glycerol + soap Soap – metallic salt of fatty acid. Trilaurin Glycerol Sodium laurate, soap Chemical Reactions of Triglycerides 3. Hydrogenation – changes a liquid oil to semi- solid or solid to make its melting point more like a saturated fat. Converts a double bond (cis) into a single bond by the addition of hydrogen gas in the presence of Ni as catalyst and heat. Complete hydrogenation → all double bonds become single Partial hydrogenation → some double bonds (cis) remains; some double bonds (cis) are converted to trans bonds → TRANS FAT Chemical Reactions of Triglycerides 4. Rancidification – process undergone by fats and oil either thru hydrolysis or oxidation. Hydrolytic rancidity – glycerides are decomposed to FA + glycerol by the action of enzyme lipase, moisture/water. Fatty acids are auto-oxidized into products w/c give unpleasant smell or taste to fats or oil. Oxidative rancidity – carbon to carbon double bonds in fatty acid residues are oxidized w/ molecular oxygen to produce short chain aldehydes & carboxylic acids giving unpleasant taste and odor to fats & oils. Anti-oxidants like vitamin C can be added to fat or oil containing foods to prevent the oxidative process. II. COMPOUND LIPIDS - esters of fatty acids and alcohols in combination with other compounds. A. Phospholipids– fatlike compounds containing alcohol, phosphoric acid and a nitrogen base. 1. Glycerophospholipids – glycerol + N-base + H3PO4 2. Sphingophospholipid – sphingosine + N-base + H3PO4 B. Glycolipids – compounds containing a fatty acid, a carbohydrate, a complex alcohol, and nitrogen but no phosphorous.  Glycerophospholipids Are fatlike substances containing glycerol, two fatty acids, nitrogen base and phosphoric acid A. lecithin or phosphatidyl choline = glycerol + 2 fatty acids + H3PO4 + N-base, choline B. cephalin or phosphatidyl ethanolamine = glycerol + 2 fatty acids + H3PO4 + N- base, ethanolamine  Sphingophospholipid Do not contain glycerol. Contains an amino alcohol, sphingosine Has one fatty acid group + H3PO4 + N- base, choline Found in storage fat cell of plants and animals. Consumed to help provide energy for the life processes. Example: sphingomyelin  GLYCEROPHOSPHO LIPID Red – glycerol portion N-base for cephalin - ethanolamine Violet – fatty acid N-base for lecithin - choline Green – phosphate group Lecithin Blue- & cephalin N base are found in brain & nerve tissues. Lecithin is abundant in the cell membrane. Sources: egg yolk, yeast, wheat germ  Sphingophosphol ipid Sphingomye lin Sphingosine unit is an amino Sphingomyelin – found I the myelin alcohol. sheath surrounding nerve cells; are N – base is choline common constituents of plasma membrane.  GLYCOLIPIDS Examples: cerebroside, ganglioside Ceramide – composed of sphingosine + fatty acid Cerebroside - found in the cell membranes of muscle and nervous tissues. Galactocerebrosides are the main glycosphingolipid in the brain. III. STEROIDS – a kind of hormone composed of three cyclohexane rings and one cyclopentane ring. The rings are assigned letters A,B,C and D respectively. Steroids include adrenal-cortical hormones, all sex hormones, bile acids and sterols of vertebrates. Steroids are hydrophobic and are insoluble in water.  Cholesterol Most abundant sterol (steroid + alcohol) in the human body. A component of cell membranes and a precursor for other steroid-based lipids. Widely distributed in all cells of the body especially the nervous tissues. It occurs in animal fats but not in plant fats. Serves as a plasma membrane component in all animal cells –in RBC. Serves as a raw material for the synthesis of sex and adrenocorticoid hormones, vitamin D and bile salts.  Cholesterol Structure Cholesterol is insoluble in water. It travels in the blood stream in the form of lipoproteins. The different types of cholesterol found in the blood cells are triglycerides, LDL (Low density lipoprotein), HDL(high density lipoprotein), and VLDL(very low density lipoprotein) Cholesterol What structures do you see ininthe is synthesized the following carbon atoms: C3, liver C5 & C6, C18 & C19, C17 ? Topics to be reported: 1. Lipoproteins 2. Bile acids 3. Sex hormones (progesterone, estradiol, testosterone) 2 reporters Messenger Lipids: Eicosanoids Format: 5. Prostaglandin 1. Short intro including 6. Leukotriene function/s 7. Thromboxane 2. Structure in condensed Fat-Soluble vitamins structural formula or line angle formula; 8. Vitamin A discuss the functional 9. Vitamin D group/s present 10. Vitamin E 3. Trivia ***maximum of 5 slides 11. Vitamin K ***5 minutes per student Reporters on eicosanoid, one reporter starts with the main precursor. Thank You!