Lipid Chemistry CHY1025 PDF

LIPID CHEMISTRY CHY1025 - Fundamentals of Biochemistry  What are Lipids ◻ A diverse group of naturally occurring organic compounds that are soluble in non-polar organic solvents (e.g. ether, chloroform, acetone & benzene) and insoluble in water. ◻ Named for the Greek...

LIPID CHEMISTRY CHY1025 - Fundamentals of Biochemistry  What are Lipids ◻ A diverse group of naturally occurring organic compounds that are soluble in non-polar organic solvents (e.g. ether, chloroform, acetone & benzene) and insoluble in water. ◻ Named for the Greek word lipos, which means “fat.”  Functions of Lipids Store energy within fat cells. Plants store energy in the form of starch - for animals, it is more economical to store energy in fats. -the burning of fat produces more than twice as much energy (about 9 kcal/g) as the same amount of carbohydrate (4 kcal/g). Animals store carbohydrates in the form of glycogen for quick energy when required.  Function of Lipids They are apart of membranes that separate compartments of aqueous solutions from each other. Human body chemistry is heavily based on water The body needs insoluble compounds for the membranes that separate compartments containing aqueous solutions.  Function of Lipids Chemical messengers Primary messengers such as steroid hormones, deliver signals from one part of the body to another. Secondary messengers such as prostaglandins and thromboxanes mediate hormonal response Functions of Lipids Buoyancy – lipids are less dense than water so help animals to float Protect organs (cushioning) Provides insulation –example whale’s blubber Precursor of hormones Aids in the transport and absorption of fat- soluble vitamins (A, D, E, K)  Lipids 1. Simple lipids: (Waxes, Fats & Oils) Store energy, insulation 2. Complex lipids Cell membrane (Glycerophospholipids) 3. Steroid (Cholesterol & steroid Chemical hormones) messenger Cell membrane 4. Eicosanoids Pain, fever, inflammation  Lipids Lipids can be categorized as: 1. Hydrolyzable lipids can be converted into small molecules by aqueous hydrolysis.  Lipids Lipids can be categorized as: 2. Nonhydrolyzable lipids cannot be cleaved into smaller molecules by aqueous hydrolysis. Waxes The simplest fatty acid esters in nature Wax is usually a mixture of long chain fatty acid and long chain alcohol esters. Secreted by sebaceous glands in the skins of animals and perform mostly external functions Waxes Long chain fatty acid + long chain fatty alcohol Example beeswax – ester formed from: ◦ 30 carbon alcohol –triacontanol ◦ 16 carbon acid – palmitic acid Importance of Wax Forms protective coating on most fruits, berries, leaves and animal furs Ear wax protect the eardrum from injury by forming a barrier between the ear canal and the external world It carries dirt, hair, dead cells and other debris out of the ear canal  Waxes Because of their long nonpolar C chains, waxes are very hydrophobic. O Beeswax CH3(CH2)14 C O(CH2)29CH3 (myricyl palmitate) hydrophobic hydrophobic region region They form protective coatings: - In plants, they help prevent loss of water and damage from pests. - In humans and animals, provide waterproof coating on skin and fur.  Beeswa Carnaub x a Coatin g Jojob a Lanolin from lotion wool s Wax Block Diagram  Triglycerides/ Triacylglycerol Triacylglycerols (TAGs) are fats and oils of plant or animal origin They are a source of energy in foods. Exists in liquid (oil) Triglycerides Triglycerides are triesters of glycerol and long-chain carboxylic acids called fatty acids. A fatty acid contains a long unbranched carbon chain attached to a carboxylic group at one end. The alcohol of triglycerides is always glycerol The carboxylic acid component may consist of any number of fatty acids. Triglycerides Triglyceride  Esterificatio n glycerol three fatty acids triacylglycerol + 3H2O Aci d  Triacylglycerols (Triglycerides) Simple triacylglycerols have three identical fatty acid side chains. Mixed triacylglycerols have two or three different fatty acids. Triglycerides ◻ All three hydroxyl groups of glycerol are esterified. ◻ Triglycerides are the most common lipids ◻ Monoglyceride – only one OH group esterified ◻ Diglyceride – two OH group esterified by fatty acids Triglycerides ◻ All three fatty acids may be identical or may be different. ◻ The ester groups of fatty acids are polar. ◻ The hydrophobic nature of triglycerides is caused by the long hydrocarbon chains. Biological Functions of Triglycerides Triglyceride is one of the 3 nutrients (along with protein and carbohydrates) that supply calories to the body. The primary function of triglyceride in animals is as an energy reserve. Triglyceride provides 9 calories per gram, more than twice the number provided by carbohydrates or protein. Biological Functions of Triglycerides Triglycerides serves as the storage substance for the body's extra calories. It fills the fat cells (adipocytes) that help insulate the body. Adipose tissue is most abundant in the abdominal cavity and the subcutaneous layer. Men – 21% fat Women - 26% fat  Biological Functions of Triglycerides When the body has used up the calories from carbohydrates, which occurs after the first 20 minutes of exercise, it begins to depend on the calories from fat. Healthy skin and hair are maintained by fat. Fat helps the body absorb and move the vitamins A, D, E, and K through the bloodstream.  Biological Functions of Triglycerides ◻ About 98% of the lipids in our diet are triglycerides, the remaining 2% consists of complex lipids and cholesterol. ◻ Triglycerides cannot pass through cell membranes freely. Enzymes called lipoprotein lipases must break down triglycerides into free fatty acids and glycerol. Biological Functions of Triglycerides- Contd. ◻ The amount of fat in the diet, especially saturated fat is a health concern for a number of years. ◻ High levels of triglycerides in the bloodstream may result in atherosclerosis (hardening of the arteries) resulting in the risk of heart disease and stroke.  Fatty acids ◻ Fatty acids are long, unbranched hydrocarbon chains with a carboxylic acid group at one end ◻ Fatty acids have a polar hydrophillic head and a non-polar hydrophobic tail ◻ The hydrophobic portion is much bigger than the hydrophillic portion hence fatty acids are insoluble in water Water Solubility of Fatty Acids ◻ Hydrophobic part of molecule dominates: very insoluble in water ◻ Forms micelles in water ◻ If a fatty acid has no carbon-carbon double bond it is a saturated fatty acid. ◻ If a fatty acid has only ONE carbon – carbon double bond, monounsaturated fatty acid ◻ More than one, polyunsaturated fatty acid ◻ In naturally occurring fats and oils, if double bonds are present, they are usually ‘cis’ rather than ‘trans’ Fatty acids  Saturated and unsaturated Fatty acids Saturated fatty acids have no double bonds in their long hydrocarbon chains. Stearic acid: CH3 (CH 2 ) 16COOH They are solids at room temperature. Packed together → Maximum London dispersion forces  Saturated and unsaturated Fatty acids Unsaturated fatty acids have 1 or more double bonds (generally cis) in their long hydrocarbon chains. Oleic acid: CH3 (CH 2 ) 7 CH=CH(CH2 ) 7 COOH They are liquids at room temperature. They can not pack together → London dispersion forces ↓ ◻ Palmitic acid (16 carbons) and stearic acid (18 carbons found in lard, meats, most fats & oils) are the most common saturated acids. ◻ Oleic and linoleic acids (both 18 Carbons) are the most common unsaturated fatty acids. Monounsaturated – oleic acid at C9-C10 – olive oil Polyunsaturated – linoleic acid and linolenic acid (needed for synthesis of other lipids in the body but the body does not produce them – ESSENTIAL fatty acids * * * * * * * * saturated Fatty Acids Fatty Acid # of Carbons # of C=C lauric 12 0 myristic 14 0 palmitic 16 0 stearic 18 0 Unsaturated Fatty Acids Fatty Acid # of Carbons # of C=C oleic 18 1 linoleic 18 2 linolenic 18 3 arachadonic 20 4 ◻ Oleic Acid – C18:1 Δ9 ◻ Linoleic Acid – C18:2 (Δ9,12) ◻ Linolenic Acid – C18: 3 (Δ9,12,15) Essential Fatty Acids ◻ Essential fatty acids are required by the body but cannot be synthesized by the body and is therefore obtained from our diet. ◻ Only linolenic and linoleic acids are essential fatty acids. ◻ Nutritionist may list arachidonic acid as an essential fatty acid but our bodies can synthesize arachidonic acid from linoleic acid  Essential fatty acids ◻ Linoleic (ω 6) – two double bonds ◻ Linolenic (ω 3) – three double bonds ◻ Notice the structures of these fatty acids, count from carbon-1 to the end. You get 18 carbons ◻ Start from carbon-18 and count to the first carbon with a double bond, then to the next and you will see where the 3 and 6 come from starting from the end which is the ω- carbon. Fatty Acids ◻ Many naturally occuring fatty acids contain 2-3 double bonds in the cis position ◻ The 1 st double bond usually occurs between C-9 and C-10, the remaining tend to begin with C-12 and C-15. ◻ The carbon chains of saturated fatty acid tend to be fully extended because this minimizes repulsion between neighboring methylene groups (CH2). ◻ The cis conformation of the double bond of an unsaturated fatty acid puts a rigid bend in the carbon chain that interferes with packing causing reduced van der Waals attractions between molecules ◻ Therefore, unsaturated fatty acids have lower melting points Fatty Acids ◻ The cis conformation of the double bond of an unsaturated fatty acid puts a rigid bend in the carbon chain that interferes with packing causing reduced van der Waals attractions between molecules ◻ Therefore, unsaturated fatty acids have lower melting points. ◻ The more double bonds (unsaturation) the lower the melting points of the fatty acids Linolenic Acid (omega-3 fatty acid) Linoleic Acid (omega-6 fatty acid) Arachidonic Acid ω-3 AND ω-6 FATTY ACIDS ◻ They are obtained from the diet ◻ Fish, flaxseed, canola oil, pumpkin seed, sunflower seed, leafy vegetables & walnuts ◻ They may prevent osteoporosis, used to make eicosanoids ◻ They affect inflammation, mood and behaviour, eg. hyperactivity BENEFITS OF ω-3 ACIDS ◻ Omega 3 fatty acids lowers the tendency for blood platelets to stick together. ◻ Diets high in omgea-3 fatty acids can help to reduce the possibility of developing heart disease. ◻ Omega-3 are considered to: lower the risk of stroke, also of heart attack and reduce menstrual pain Essential fatty acids ◻ A deficiency of essential fatty acids in infants can result in skin dermatitis. ◻ Adults do not usually have a deficiency of essential fatty acids. Essential fatty acids ◻ Both fish and vegetable oils have high levels of unsaturated fats. ◻ Vegetable, grains oils from plant – omega-6 acids ◻ Fish oils – omega-3 acids  Fat & Health - It is recommended that no more than 20-35% of a person’s caloric intake should come from lipids. - A high intake of saturated triacylglycerols is linked to heart disease. - Saturated fats stimulate cholesterol synthesis in the liver, which can lead to cholesterol plaques building up inside arteries. - The result is high blood pressure, heart attack, and even stroke. - Unlike other vegetable oils, oils from palm and coconut trees are very high in saturated fats.  Fat & Health - Unsaturated triacylglycerols (omega-3 fatty acids from fish) lower the risk of heart disease by decreasing the level of cholesterol in the blood. - However, if the double bond of the unsaturated triacylglycerol is trans, the beneficial effect is lost. - Trans fats, which are primarily synthesized instead of naturally occurring, act like saturated fats and increase the cholesterol levels in the blood. Physical Properties of Triglyceride ◻ Fats from animals are usually solid at room temperature. ◻ Fats from fish or oils are usually liquid at room temperature. Liquid fats are called oils. ◻ Fat – a mixture of triglycerides containing a high proportion of long chain saturated fatty acids. ◻ Oil – a mixture of triglycerides containing a high proportion of long chain unsaturated fatty acids or short chain saturated fatty acids. ◻ The structural difference between solid fats and liquid oils is the degree of unsaturation Physical Properties of Triglycerides ◻ Solid animal fat contains mainly saturated fatty acids. ◻ Vegetable oils contain high amounts of unsaturated fatty acids ◻ * even solid fats contain some unsaturated acids and liquid fats contain some saturated acids. Physical Properties of Triglycerides ◻ Saturated fatty acids fit closely together in a regular pattern and this allows strong interaction to occur between the carbon chains. ◻ As a result saturated fatty acids are usually solids at room temp. ◻ In unsaturated fatty acids, the cis double bond causes a kink giving the molecule an irregular shape. As a result there is fewer interactions between the carbon chains. ◻ Most unsaturated fats are liquid at room temp Physical Properties of Triglycerides ◻ Coconut oil only has a small amount of unsaturated acids. ◻ It is liquid because it is rich in low molecular weight fatty acids (mainly lauric acid). Physical Properties of Triglycerides ◻ Pure fats and oils are colourless, odourless and tasteless. ◻ The taste odours and colours are caused by small amounts of other substances dissolved in the fat or oil. ◻ Melting point increases with size (lesser effect) and decreases with unsaturation (greater effect)  Chemical Nature of Triglycerides ◻ The chain lengths of the fatty acids in naturally occurring triglycerides vary, but most contain 16, 18, or 20 carbon atoms. ◻ Natural fatty acids found in plants and animals are typically composed of only even numbers of carbon atoms, reflecting the pathway for their biosynthesis from the two-carbon building-block acetyl CoA. ◻ Bacteria, however, possess the ability to synthesize odd- and branched-chain fatty acids. As a result, ruminant animal fat contains odd-numbered fatty acids, such as 15, due to the action of bacteria in the rumen. Chemical Properties of Fatty Acids ◻ When fatty acids are not attached to other molecules, they are known as "free" fatty acids. ◻ Fatty acids are important sources of fuel because when metabolized, they yield large quantities of ATP. ◻ Many cell types, can use either glucose or fatty acids for fuel. ◻ In particular, heart and skeletal muscle prefer fatty acids. Reactions of Triglycerides- Saponification ◻ Saponification is a process that produces soap, usually from fats and lye. ◻ Saponification involves base (usually NaOH) hydrolysis of triglycerides, to form the sodium salt of a carboxylates (soap). ◻ The triglyceride is treated with a strong base (e.g., lye), which accelerates cleavage of the ester bond and releases the fatty acid salt (soaps) and glycerol. ◻ Adding NaCl to the mixture then causes the soap to ppt.  Reactions of Triglycerides- Saponification ◻ Perfumes can be added if a toilet soap is desired ◻ Sand, sodium carbonate and other fillers can be added to make scouring soap. ◻ Sodium salts are almost completely miscible with water.  3- Saponification (Basic Hydrolysis) -- With KOH or the oils that are polyunsaturated gives softer soaps (liquid soaps). - Soaps are typically made from lard (from hogs), tallow (from cows or sheep), coconut oil, or palm oil. - All soaps work in the same way, but have different properties depending on the lipid source, length of C chain, and degree of unsaturation. 3- Saponification (Basic Hydrolysis) + 3NaOH H Heat H + 3 Na+-O “soap” Salt of fatty acid H  Soap s Hydrophobic part: nonpolar Hydrophilic part: polar (remains in contact with environment)  Soap s When soap is mixed with dirt (grease, oil, and …), soap micelles “dissolve” these nonpolar, water-insoluble molecules. Reactions of Triglycerides- Hydrogenation ◻ Unsaturated fatty acids present in triglycerides accept hydrogen such as at the double bond. ◻ This process is known as hydrogenation ◻ Commercial cooking fats are manufactured by partial hydrogenation of vegetable oils ◻ This results in partially hydrogenated fat Reactions of Triglycerides- Hydrogenation ◻ Complete hydrogenation is avoided because a completely saturated triglyceride is hard and brittle. ◻ One commercial advantage is to give the fat a longer shelf life. Polyunsaturated oils tend to react by auto- oxidation causing them to become rancid. ◻ One drawback however is that the catalyst isomerizes some of the unreacted double bonds from the natural cis arrangement to the unnatural trans. ◻ Several studies have reported trans fats to raise LDL- cholesterol and lower HDL-cholesterol.  1- Hydrogenation - Hydrogen adds to the double bonds of unsaturated fats (using transition metal catalyst such as Ni). H H H H _ N C=C + H → _C_C_ _ 2 i - Melting point is increased. H H - Liquid oils are converted to semi-solid fats. Hydrogenation  2- Hydrolysis Triacylglycerols are hydrolysis (split by water) in the presence of strong acid or lipase (digestive enzyme). + 3H2O H H + 3HO H+ or Lipase H  Metabolism of triacylglycerols - Humans store energy as triacylglycerols in adipose cells below the surface of the skin, in the breast area, and surrounding internal organs. - The number of adipose cells is constant; weight gained or lost causes them to swell or shrink, but not decrease or increase in number. - To metabolize triacylglycerols for energy, the esters are hydrolyzed by enzymes called lipases. - Complete metabolism of a triacylglycerol yields CO2, H2O, and a great deal of energy.  phospholipids Phospholipids are lipids that contain a P atom. Two common types:  phospholipids 1. Phosphoacylglycerols (glycerophospholipids): They are the main component of most cell membranes. Structurally, they resemble a triacylglycerol, except the third fatty acid has been replaced with a phosphodiester bonded to an alcohol. Fatty acid Fatty acid Amino alcohol  Cell Membrane Carbohydra te Phospholip id bilayer Nonpolar Hydrophobic Polar Hydrophilic Semipermeable : selected nutrients can enter and waste products can leave. Fluid mosaic model Importance of Phospholipids ◻ Phospholipids are amphipathic molecules, meaning they possess both hydrophilic (water-loving) and hydrophobic (water-fearing) regions. ◻ This unique structure enables phospholipids to form the foundation of biological membranes. Structural Role of Phospholipids in Membranes ◻ Phospholipids are the major building blocks of biological membranes. They form a lipid bilayer structure in which the hydrophilic head groups face the aqueous environment, while the hydrophobic fatty acid tails are shielded from water. ◻ This arrangement provides structural integrity to cell membranes, separating the internal contents of cells from their surroundings. ◻ Phospholipids also contribute to the fluidity and flexibility of membranes, allowing for membrane dynamics and cell movements. Selective Permeability ◻ The phospholipid bilayer acts as a selective barrier that regulates the entry and exit of substances into and out of cells. ◻ The hydrophobic core of the bilayer restricts the passage of hydrophilic molecules and ions, while small hydrophobic molecules can diffuse through the lipid tails. ◻ This selective permeability allows cells to maintain internal conditions, control the transport of essential molecules, and prevent the entry of harmful substances.  phospholipids 2. Sphingomyelins: They differ in two ways: 1. They do not contain a glycerol backbone, they have a sphingosine backbone instead. sphingosine 2. They do not contain an ester; their single fatty acid is bonded to the backbone by an amide bond.  phospholipids 2. Sphingomyelins: The myelin sheath, the coating that surrounds nerve cells, is rich in sphingomyelins. Glycerophospholipid Sphingomyelin Glycolipid  Sphingolipids ◻ This group contains both: Sphingomyelin Glycolipid ◻ The long chain alcohol amine called sphingosine replaces glycerol ◻ One fatty acid is attached at the amine group as an amide ◻ the -OH at C-3 is free and the –OH at C-1 is incorporated into either a phosphate ester or a glycosidic bond to a sugar Sphingophospholipids ◻ Sphingomyelins - major components of the coating around nerve fibers ◻ Some of these are also called phospholipids, but remember they do not have glycerol as the alcohol portion ◻ The alcohol sphingosine (18 C) is in place of glycerol and it also has the phosphate ester, but at C-1 and only one fatty acid, as the amide at C-2, while C-3 –OH is free, C4 – C5 is a double bond  Glycolipids ◻ Glycolipids – also sphingolipids ◻ The phosphate group at C-1 is replaced by a sugar example is with D-galactose, abundant in brain nerve cell membranes  Conjugated lipids ◻ Glycolipids are conjugated lipids because they have a lipid portion and a sugar portion linked together ◻ Other conjugated substances are glycoprotein, proteoglycan, lipoprotein, haemoglobin Steroids ◻ Terpenoids are the compounds that are responsible for the smell and flavour in “essences” essential oils – volatile oils, of roses, jasmine, banana, others. ◻ Steroids are derived from terpenoids. Steroids ◻ Cholesterol is the most well-known steroid, it is used in cell membranes and used to make other steroids, it is the most abundant steroid in humans ◻ Steroids are important as hormones and as bile acids that are essential to fat digestion ◻ They all have the 4 fused rings basic structure  Steroids Steroids have: A steroid nucleus which is 4 carbon rings. Attached groups that make the different types of compounds. (steroid nucleus) No fatty acids.  Cholesterol Cholesterol: Is the most abundant steroid in the body. Insoluble in water (need a water soluble carrier). Has methyl CH3- groups, alkyl chain, and -OH attached to the steroid nucleus.  Cholesterol Cholesterol: Is obtained from meats, milk, and eggs. Is synthesized in the liver from fats, carbohydrates and proteins. Is needed for cell membranes, brain and At artery clogged by nerve tissue, steroid hormones, and cholesterol plaque Vitamin D. Clogs arteries when high levels form plaque (because it is insoluble in blood). No cholesterol in vegetable and plants. Gallstones form in gallbladder Cholesterol ◻ Cholesterol from the diet is absorbed from the small intestine, metabolized and stored in the liver. ◻ It is secreted by the liver when required ◻ With an excessive intake of a fat rich diet, cholesterol may begin to build-up in the arteries Functions of Cholesterol ◻ Contributes to the structure of cell membranes ◻ Makes digestive bile acids ◻ Precursor for hormones ◻ Facilitate the body to produce vitamin D Lipids Found in Biological Membranes ◻ Phospholipids ◻ Glycolipids ◻ Sterol  Lipoproteins Water-soluble form of lipids Triacylglycerols (soluble in blood) Spherical particles Polar surface and nonpolar inner Transport lipids (cholesterol) through the bloodstream to tissues where they are stored, Used for energy, or to make hormones. Lipoproteins ◻ HDL (High Density Lipoprotein) – plays a primary role in removing excess cholesterol from cells and returning it to the liver where it is metabolized and eliminated ◻ LDL (Low Density Lipoprotein) – deliver cholesterol and cholesterol esters to peripheral tissues. Lipoprotein ◻ VLDL – Very Low Density Lipoprotein – synthesized by the liver. Delivers triglycerides, cholesteryl esters and cholesterol to peripheral tissues. ◻ Chylomicrons – largest lipoproteins with the lowest density. Synthesized by the intestine – Transfer triglycerides and cholesteryl esters to the tissues  Steroid Hormones A hormone is a molecule that is synthesized in one part of an organism, which then elicits a response at a different site. Two types of steroids hormones: 1. Sex hormones Estrogens & progestins in females Androgens in males 2. Adrenal Cortical Steroids  Sex Hormones Estrogens (Female Sex Hormones): The estrogens estradiol and estrone control development of secondary sex characteristics, regulate the menstrual cycle, and are made in the ovaries.  Sex Hormones Progestins (Female Sex Hormones): The progestin progesterone is called the “pregnancy hormone”; it is responsible for the preparation of the uterus for implantation of a fertilized egg.  Sex Hormones Androgens (Male Sex Hormones): Testosterone and Androsterone are androgens made in the testes. They control the development of secondary sex characteristics in males.  Sex Hormones - Synthetic androgen analogues, called anabolic steroids, promote muscle growth. - They have the same effect as testosterone, but are more stable, so they are not metabolized as quickly. - They have come to be used by athletes and body builders, but are not permitted in competitive sports. - Prolonged use of anabolic steroids can cause physical and psychological problems.  Adrenal Cortical Steroids Aldosterone regulates blood pressure and volume by controlling the concentration of Na + and K + in body fluids. Cortisone and cortisol serve as anti-inflammatory agents, which also regulate carbohydrate metabolism. aldosterone cortison e cortisol  Eicosanoids ◻ Group of compounds derived from 20-carbon unsaturated fatty acids (eicosanoic acids) and synthesized throughout the body. Eg. arachidonic acid, which is made from linoleic and linolenic acid  Eicosanoids Prostaglandins, Leukotrienes and Thromboxanes are types of eicosanoids (20 C atoms derived from the fatty acids). - All eicosanoids are very potent compounds, which are not stored in cells, but rather synthesized in response to external stimulus. - Unlike hormones they are local mediators, performing their function in the environment in which they are synthesized.  Prostaglandins Prostaglandins are carboxylic acids that contain a five-membered ring and have a wide range of biological activities. Prostaglandins ◻ There are several different types of prostaglandins and they play a role in regulating bodily processes: Responsible for uterine contractions during menstruation Activate or prevent platelet buildup for blood clot formation Cause vasodilation (widening of blood vessels) or vascoconstriction (narrowing of the blood vessels) Cause bronchoconstriction (narrowing of the air passageways or bronchodilation (widening of the air passageways) Induce labour through uterine contraction Cause fever Prostaglandins ◻ Prostaglandins have a short shelf life and duration of action ◻ Several different tissues throughout your body can make prostaglandins Prostaglandins ◻ If you cut your finger, prostaglandins will work in the following ways: Affected tissues in your finger would release prostaglandins that would signal the platelets in the blood to stick together and form a blood clot at the injury site to stop the bleeding. Prostaglandins would also narrow the affected blood vessels to reduce blood loss Prostaglandins would also be release to elicit an anti- inflammatory response causing blood vessels to leak into the tissues (swelling). This isolate any foreign substances that may have entered through the broken skin from further contact with the tissues of the body. Prostaglandins ◻ Hormone like action Regulates fever, contractions, inflammation Induces labor, and asthma Made from arachadonic acid Synthesis inhibited by aspirin and cyclooxygenase inhibitors PROSTAGLANDINS  Prostaglandins Prostaglandins are responsible for inflammation. - Aspirin and ibuprofen relieve pain and inflammation by blocking the synthesis of these molecules. - Prostaglandins also decrease gastric secretions, inhibit blood platelet aggregation, stimulate uterine contractions, and relax smooth muscles. - There are two different cylcooxygenase enzymes responsible for prostaglandin synthesis called COX-1 and COX-2.  Prostaglandins COX-1 is involved in the usual production of prostaglandins. COX-2 is responsible for additional prostaglandins in inflammatory diseases like arthritis. - Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin and ibuprofen inactivate both COX-1 and -2, but increase risk for stomach ulcer formation. - Drugs sold as Vioxx, Bextra, and Celebrex block only the COX-2 enzyme without affecting gastric secretions. Thromboxanes ◻ The distinguishing features of thromboxanes is a 6- membered ether containing ring. ◻ Named for its roles in blood clot (thrombosis) ◻ Vascoconstrictor that promotes platelet aggregation Leukotrienes ◻ Possess a conjugated triene system and one or more oxygen functions ◻ Conjugated alkenes have alternate single and double bonds between the carbon atoms  Leukotrienes Asthma is characterized by chronic inflammation, so inhaled steroids to reduce this inflammation are commonly used. Leukotrienes are molecules that contribute to the asthmatic response by constricting smooth muscle of the lung. New asthma drugs act by blocking the synthesis of leukotriene C4, which treat the disease instead of just the inflammation symptoms.  EICOSANOID STRUCTURES Leukotriene B 4. Note the 3 conjugated Prostaglandin E1. The 5-member ring is double bonds. characteristic of the class. Thromboxane A2. Oxygens have moved into the ring.  Vitamins They are organic compounds required in small quantities for normal metabolism. They must be obtained from the diet (our cells cannot synthesize them). Vitamins are either water soluble or fat soluble. The four fat-soluble vitamins (A, D, E, and K) are lipids and nonpolar. They are found in fruits, vegetables, fish, liver, and dairy products. Excess vitamins are stored in adipose cells to be used when needed.  Vitamins Vitamin A It is found in liver, fish, and dairy products, and is made from β-carotene (the orange pigment in carrots). It is needed for vision and for healthy mucous membranes. Vitamin A deficiency causes night blindness and dry eyes and skin.  Vitamins Vitamin D Vitamin D can be synthesized from cholesterol. It can be obtained in the diet from many foods, especially milk, and helps regulate Ca and P metabolism. A deficiency of vitamin D causes rickets (bone malformation).  Vitamins Vitamin E Vitamin E is an antioxidant, protecting unsaturated side chains in fatty acids from unwanted oxidation. Deficiency of vitamin E causes numerous neurological problems, although it is rare.  Vitamins Vitamin K Vitamin K regulates the synthesis of clotting proteins (prothrombin), and deficiency of this leads to excessive or fatal bleeding.