Linoleic acid function

C-21 dicarboxyhc acids are produced by Westvaco Corporation in Charleston, South Carolina in multimillion kg quantities. The process involves reaction of tall oil fatty acids (TOFA) (containing about 50% oleic acid and 50% hnoleic acid) with acryhc acid [79-10-7] and iodine at 220—250°C for about 2 hours (90). A yield of C-21 as high as 42% was reported. The function of the iodine is apparendy to conjugate the double bond in linoleic acid, after which the acryhc acid adds via a Diels-Alder type reaction to form the cycHc reaction product. Other catalysts have been described and include clay (91), palladium, and sulfur dioxide (92). After the reaction is complete, the unreacted oleic acid is removed by distillation, and the cmde C-21 diacid can be further purified by thin film distillation or molecular distillation. 

Some fatty acids are not synthesized by mammals and yet are necessary for normal growth and life. These essential fatty aeids include llnoleic and y-linolenic acids. These must be obtained by mammals in their diet (specifically from plant sources). Arachidonic acid, which is not found in plants, can only be synthesized by mammals from linoleic acid. At least one function of the essential fatty acids is to serve as a precursor for the synthesis of eicosanoids, such as... 

We previously described [25] the function of soybean lipoxygenase-1 in a biphasic system (modified Lewis cell) composed of an aqueous phase (borate buffer) and octane. The substrate of the reaction is linoleic acid (LA) and the main product is hydro-peroxyoctadecadienoic acid (LIP). The system involves two phenomena LA transfer from the organic to the aqueous phase and lipoxygenase kinetics in the aqueous medium. 

As mentioned in the introduction, 3-hydroxy fatty acids with functional groups can also be incorporated in poly(3HAMCL). Table 2 illustrates this with many examples of alkenes, 3-hydroxyalkenoic acids, and substituted 3-hy-droxyalkanoic acids that are readily integrated in poly(3HAMCL). Long chain fatty acids have also been used successfully as substrates for poly(3HAMCL) production. De Waard et al. [44] used oleic acid and linoleic acid to produce... 

Tricon S, Burdge G C, Kew S, Banerjee T, Russell J J, Jones E L, Grimble R F, Williams C M, Calder P C and Yaqoob P (2004), Effects of cis-9, trans-11 and trans-10, cis-12 conjugated linoleic acid on immune function in healthy humans , American Journal of Clinical Nutrition, 80, 1626-1633. 

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... 

Fitzpatrick, K.C., Regulatory issues related to functional foods and natural health products in Canada Possible implications for manufacturers of conjugated linoleic acid, Am J Clin Nutr, 79, 1217S, 2004. 

In addition to nutritional value and flavor, health concerns must also be a part of any discussion of food quality. Among the most interesting of food products with a health related function are the CLAs or conjugated dienoic derivatives of linoleic acid. The CLAs were originally found in meat (beef) extracts and have been shown to be a potent inhibitor of carcinogen-induced neoplasia in the epidermis and forestomach in mice and of the mammaiy in rats Chapter 21). 

The conversion of oleoyl-CoA to linoleoyl-CoA is accomplished by some insects118 but does not take place in most animals. As a result of this biosynthetic deficiency, polyunsaturated fatty acids such as linoleic, linolenic, and the C20 arachidonic acid are necessary in the diet (Box 21-B). One essential function of linoleic acid is to serve as a precursor of prostaglandins and related prostanoids (Section D). Dietary linoleate is converted to its Co A derivative and then by sequential A6 desaturation,119 elongation, and then A5 desaturation, to the 20 4 (A5 8 11 14) arachidonoyl-CoA (Fig. 21-2, lower right). These acids are referred to as 0)6 because of the position of the last double bond. Linolenic acid can be converted in an analogous fashion to the CoA derivative of the 20 5 (A5 8 11 14 17 co6) eicosapentaenoic acid (EPA). The 22 6 docasahexaenoic acid (DHA Fig. 21-2) is apparently formed by elongation of the 22 5 acyl-CoA to 24 5, desaturation, transfer to a peroxisome or mitochondrion, and p oxidation to shorten the chain.953... 

Burr and Burr reported in 1929 a new deficiency disease produced by the rigid exclusion of fat from the diet. 1 Rodents fed a fat-free diet showed reduced growth and reproductive failure, accompanied by two prominent changes in the skin, that is, increased scaliness and impaired barrier function.1,2 Reversal of the features of deficiency by administration of linoleic acid (LA), led to the concept of essential fatty acids (EFA) that cannot be synthesized by the higher animals.2 Similarities between the clinical features of EFA deficiency and atopic dermatitis led Hansen in 1937 to discover low blood levels of unsaturated fat in atopic children,3 and he later reported that EFA-deficient infants developed an eczematous rash, which responded to LA supplements.4 Several studies had previously examined a range of dietary oil supplements in atopic dermatitis,5-8 with generally reported benefit. 

Hansen, H.S. and Jensen, B., Essential function of linoleic acid esterified in acylglucosyl ceramide and acylceramide in maintaining the epidermal water permeability barrier evidence from feeding studies with oleate, linoleate, arachidonate, columbinate and alpha-linoleate, Biochim. Biophys. Acta, 834, 357, 1985. 

Field, CJ. and Schley, P.D., Evidence for potential mechanisms for the effect of conjugated linoleic acid on tumor metabolism and immune function lessons from n-3 fatty acids, Am. J. Clin. Nutr., 79, 1190S, 2004. 

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