Eicosapentaenoic acid structure

Cold-water frsh like salmon are rich in omega-3 fatty acids, which have a double bond three carbons in from the noncarboxyl end of the chain and have been shown to lower blood cholesterol levels. Draw the structure of 5,8,11,14,17-eicosapentaenoic acid, a common example. (Eicosane = C20H42)... 

Dietary polyunsaturated fatty acids (PUFAs), especially the n-3 series that are found in marine fish oils, modulate a variety of normal and disease processes, and consequently affect human health. PUFAs are classified based on the position of double bonds in their lipid structure and include the n-3 and n-6 series. Dietary n-3 PUFAs include a-linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) whereas the most common n-6 PUFAs are linoleic acid, y-linolenic acid, and arachidonic acid (AA). AA is the primary precursor of eicosanoids, which includes the prostaglandins, leukotrienes, and thromboxanes. Collectively, these AA-derived mediators can exert profound effects on immune and inflammatory processes. Mammals can neither synthesize n-3 and n-6 PUFAs nor convert one variety to the other as they do not possess the appropriate enzymes. PUFAs are required for membrane formation and function... 

Some polyunsaturated fatty acids were tested for the production of hydroxy fatty acids by PR3 because polyunsaturated fatty acids contained a, 4-ds,cis-diene unit which could serve as a key structural element for the hydroxylation by lipoxygenase. When eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) carrying l,4-d c y-diene unit were used as substrates for bioconversion by PR3, new products were detected on TLC analysis as shown in... 

The structure of the FA eicosapentaenoic acid (EPA) bound to PPAR-d has been determined (PDB entry 3GWX) [35]. The ligand-binding pocket of PPAR-d assumes roughly a Y shape with each of the three arms approximately 12 A in length. One arm of the Y is composed of a mix of hydrophobic residues and polar residues and is capped by two residues from helix-12. This is the only arm of the Y that is substantially polar in character. Another arm of the Y is composed of hydrophobic residues and is sealed by the last residue of helix-1, and the loop between helices-1 and -2. The third arm of the Y-shaped pocket is composed mainly of hydrophobic residues with a few polar residues. The interior of the ligand-binding pocket is accessible via a channel that is exposed to solvent [35]... 

DNP dinitrophenyl CBZ carbobenzoxy OBzl benzylesters /3NA naphthyl amide TCP tetrachlorofluorescein amaryllis alkaloids crinine, powelline, and crinamidine vinca alkaloids vincamine and vincine structural isomers 2- and 6-nitro-3-acetamido-4-chlorobenzoic acid stereoisomers 4-methoxymethyl-l-methyl-cyclohexane carboxylic acid fish oil mixture of docosahexaenoic acid and eicosapentaenoic acid NDGA nordihydroguaiaretic acid. 

Puri BK, Richardson AJ, Horrobin DF, Easton T, Saeed N, Oatridge A, etal. Eicosapentaenoic acid treatment in schizophrenia associated with symptom remission, normalisation of blood fatty acids, reduced neuronal membrane phospholipid turnover and structural brain changes. Int J Clin Prac 2000 54( 1 ) 57—63. 

Although most hpids required for cell structure, fuel storage, or hormone synthesis can be synthesized from carbohydrates or proteins, we need a minimal level of certain dietary hpids for optimal health. These hpids, known as essential fatty acids, are required in our diet because we cannot synthesize fatty acids with these particular arrangements of double bonds. The essential fatty acids a-linoleic and a-linolenic acid are supphed by dietary plant oils, and eicosapentaenoic acid (ERA) and docosa-hexaenoic acid (DHA) are supplied in fish oils. They are the precursors of the eicosanoids (a set of hormone-like molecules that are secreted by cells in small quantities and have numerous important effects on neighboring cells). The eicosanoids include the prostaglandins, thromboxanes, leukotrienes, and other related compounds. 

FA distribution in TAG as well as in phospholipids affects the physical properties, lipolitic and oxidative stability, and nutritional availability of lipids. In many TAG, the FA are arranged in a nonrandom distribution. In plants, monoenoic FA and PUFA are dominant at a sn-2 position (Orthoefer, 1996). In pig depot fat and in cow s milk, the TAG sn-2 position is occupied by palmitic acid. The distribution is also different in cattle and sheep depot fats (Love, 1996). In blubber seals, long-chain n-3 PUFA are esterified rather in sn-l,3 positions, whereas, in muscle, TAG in the sn-2 position that is typical for the lipid muscles of nearly all fish (Ackman, 1994). Enzymatic syntheses of structured TAG containing dY-5,8,ll,14,17-eicosapentaenoic acid (EPA) and dY-4,7,10,13,16,19-docosahexaenoic acid (DHA) in the sn-2 position with medium-chain FA at the end positions are particularly interesting (Halldorsson... 

FIGURE 3.2 (a) The relationship between the three nomenclature notations for fatty acids. Eicosapentaenoic acid (EPA) is shown as an example, (b) Representative structures of the common polyene fatty acids of the n-3 and n-6 families. 

The number of double bonds in the alkyl chains of all the prostanoids depends on the precursor fatty acid prostanoids of the 1-series (carrying one double bond) derive from dihomo-y-linolenic acid (20 3 -6), the 2-series (carrying two double bonds) from arachidonic acid (20 4 -6), and the 3-series (carrying three double bonds) from eicosapentaenoic acid (20 5n-3). Figure 2 gives the structures of prostaglandins E and F of all three series and their precursor polyunsaturated fatty acids. 

The marine metabolite 6a was isolated from the marine sponge Halichondria okadai and first reported in 1989 along with the unsaturated derivative 6b [7]. These compounds, both weak lipoxygenase inhibitors, contain 20 carbon atoms, and their biosynthesis from arachidonic acid and eicosapentaenoic acid, respectively, has been proposed. In addition to having important physiological properties, they also contain a number of unusual structural features, including a nine-membered lactone and a cyclopropane ring. The relative stereochemistry of aU the chiral centers... 

Akoh, CC and Moussata, CO (1998) Lipase-catalyzed modification of borage oil incorporation of capric and eicosapentaenoic acids to form structured lipids. J. Am. Oil Chem. Soc., 75, 697-701. 

Han, JJ and Yamane, T (1999) Enhancement of both reaction yield and rate of synthesis of structured triacylglycerol containing eicosapentaenoic acid under vacuum with water activity control. Lipids, 34, 989-995. 

Figure 1. There are two important families of PUFA the n-6 family based on linoleic add, and the n-3 family based on a-linolenic acid. Since animals - including humans - cannot produce linoleic or a-linolenic acids themselves, these acids are essential parts of the diet, obtainable only from vegetable sources or from animals which have already derived these acids from a plant source. Once ingested, the two Cjj acids can be metabolized to important and acids through a series of changes involving desaturation and elongation. The same enzymes are required for both famiUes of adds and there is competition for these. The most important acids in these sequences are arachidonic addin the h-6 series, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the n-3 series. All these adds are important components of phospholipid membranes, and the two acids are also precursors of prostaglandins and other eicosanoids. The locations of the double bonds are indicated in brackets after the abbreviated structure of each fatty acid.

FIGURE 3.2 Chemical structures of the unsaturated fatty acids, oleic acid (2), palmitoleic acid (3) linoleic acid (4), a-hnolenic acid (5), eicosapentaenoic acid (6), and docosahexaenoic acid (7). 

Haraldsson, G. G., Halldorsson, A., and Kulas, E. 2000. Chemoenzymatic synthesis of structured triacylglycerols containing eicosapentaenoic and docosahexaenoic acids /. Am. Oil Chem. Soc., 77,1139-1145. 

Christensen, M.S., Hoy, C.E., Becker, C.C., and Redgrave, T.G. 1995. Intestinal absorption and lymphatic transport of eicosapentaenoic, docosahexaenoic, and decanoic acids dependence on intramolecular triacylglycerols structure. Am. Clin. Nutr. 61 56-61. 

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