Docosahexaenoic acid polyunsaturated fatty acids

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... 

There is some evidence that, in these patients, the interconversion between the polyunsaturated fatty acids is disturbed, which restricts the formation of eicosapentaenoic and docosahexaenoic acids. Such children are less likely to have been breastfed (breast milk contains these omega-3 fatty acids) they are more likely to suffer from allergies associated with essential fatty acid deficiency and also dry skin and hair and the membranes of the erythrocytes contain less omega-3 fatty acids compared with normal children. So far, the results of supplementation of the diet of these children with this disorder have not been conclusive. 

Health Benefits of n-3 Polyunsaturated Fatty Acids Eicosapentaenoic Acid and Docosahexaenoic Acid... 

Fish oils that contain high amounts of the n-3 polyunsaturated fatty acids eiocosapentaenoic acid (EPA, 20 5, n-3) and docosahexaenoic acid (DHA, 22 6, n-3) have been suggested to decrease the risk of development of cardiovascular disease. Freshwater fish oil carp oil are not rich in n-3 polyunsaturated fatty acids, but tuna oil is rich in n-3 polyunsaturated fatty acids such as EPA and DHA Table (1) . 

Several methods have been proposed to produce polyunsaturated fatty acid (PUFA) concentrates particularly high in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Most PUFA enrichment methods are based upon a combination of techniques such as saponification, solvent extraction, urea fractionation, molecular distillation, fractionation distillation, liquid chromatography, and super critical carbondioxide extraction. Current evidence suggests that the physiological effects of omega-3 fatty acids are such that the annual world supply of fish oils will be grossly inadequate as a source of these materials, and alternative sources will be needed (Belarbi et al, 2000). 

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... 

Fish oils are a potential source of long chain n-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Clinical... 

The isoprostanes are a unique series of prostaglandin-like compounds formed in vivo via a nonenzymatic mechanism involving the free radical-initiated peroxidation of arachidonic acid. This article summarizes our current knowledge of these compounds. Herein, a historical account of their discovery and the mechanism of their formation are described. Methods by which these compounds can be analyzed and quantified are also discussed, and the use of these molecules as biomarkers of in vivo oxidant stress is summarized. In addition to being accurate indices of lipid peroxidation, some isoprostanes possess potent biological activity. This activity will be discussed in detail. Finally, in more recent years, isoprostane-like compounds have been shown to be formed from polyunsaturated fatty acids, including eicosapentaenoic acid and docosahexaenoic acid. These findings will be summarized as well. 

Fish oils are a rich source of 00-3 polyunsaturated fatty acids such as eicosapen-taenoic acid (ERA) and docosahexaenoic acid (DHA). The supplementation of Western diets with fish oils containing ERA and DHA has been recommended (68, 69), and it can be beneficial for ischemic heart disease and thromboembolic events. 

Martinez, M. (1991) Developmental profiles of polyunsaturated fatty acids in the brain of normal infants and patients with peroxisomal diseases severe deficiency of docosahexaenoic acid in Zellweger s and pseudo-Zellweger s syndomes. World Rev. Nutr. Diet. 66 87-102. 

Polyunsaturated Fatty Acids (n-3 PUFAs) and Docosahexaenoic Acid (DMA, C22 6 n-3)... 

Poulos A, Robinson BS, Ferrante A, Harvey DP, Hardy SJ, Munay AW. Effect of 22-32 carbon n-3 polyunsaturated fatty acids on superoxide production in human neutrophils synergism of docosahexaenoic acid with f-met-leu-phe and phorbol ester. Immunology 1991 73 102-108. 

First, several reports over the last 25 yr show that carbon recycling from a-linolenate in neonatal rats and near-term primate fetuses consumes the majority of a-linolenate that is not used as a fuel. Second, a-linolenate cannot be synthesized de novo by mammals and is the main dietary precursor to the n-3 long-chain polyunsaturated fatty acids (LC-PUFAs), eicosapentaenoate (20 5n-3) and docosahexaenoate (22 6n-3), which have important regulatory and membrane functions, respectively. Thus, a-linolenate is a vitamin-like nutrient that would not be expected to be easily p-oxidized or extensively carbon recycled into other lipids when it already has an important precursor role for membrane components needed for normal development of the visual and nervous systems. 

Martin RE, De Turco EBR, Bazan N. Developmental maturation of hepatic n-3 polyunsaturated fatty acid metabolism supply of docosahexaenoic acid to retina and brain. J Nutral Biochemistry 1994 5 151-160. 

Membrane lipids constitute 50-60% of the solid matter in the brain (O Brien, 1986), and phospholipids are quantitatively the most significant component of membrane lipids (Crawford and Sinclair, 1972). A major proportion of brain phospholipids contain long-chain polyunsaturated fatty acids of the two essential fatty acid classes, n-6 and n-3 (Crawford et al., 1976, O Brien et al., 1964). These fatty acids usually occupy the sn-2 position of the brain phospholipid molecules. Normally, docosahexaenoic acid (22 6n-3, DHA) is the predominant polyunsaturated fatty acid of the phospholipids of the cerebral cortex and retina. The primate brain gradually accumulates its full complement of DHA during intrauterine life and during the first year after birth (Clandinin et al., 1980a, Clandinin et al., 1980b). 

Fig. 1. Three biosynthetic pathways for major polyunsaturated fatty acids in mammals (desaturation, chain-elongation and chain-shortening steps). The site of desaturase action is shown by A9, A6, or A5. The major polyunsaturated fatty acids found in tissue lipids are linoleic (LA), arachidonic (ARA), docosapentaenoic (DPA), a-linolenic (ALA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Fatty acids are designated by the carbon chains the number of double bonds, and the position of the first double bond from the methyl terminus, as n-9, n-7, n-6, or n-3. Typical foods enriched with the indicated fatty acids are also shown.

Bazan, N.G. (1989). The metabolism of omega-3 polyunsaturated fatty acids in the eye the possible role of docosahexaenoic acid and docosanoids in retinal physiology and ocular pathology. Prog Clin Biol Res 312, 95-112. 

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