Linolenic acid from lipids

Several studies have confirmed that the seed oil from the North American variety of cranberry contains significant levels of a-linolenic acid. In a U.S. patent, Heeg et al. (4) reported the a-linolenic acid content of cranberry seed oil to be between 30% and 35% of total fatty acids. In 2003, Parker et al. (5) found 22.3% a-linolenic acid in the cold-pressed cranberry seed oil, and in 2004, Parry et al. (3) determined the oil to contain 32.0% a-linolenic acid from two different lots of the seed oil. The ratios of n-6 to n-3 fatty acids in all were low from 1.2 1 to 2 1. Also, all of the studies documented similar ratios among the rest of the common fatty acids found in cranberry seed oil, including, in order of higher amount present linoleic, oleic, palmitic, stearic, and eicosadienoic (20 2) acids (Table 1). In addition to a-linolenic acid, cranberry seed oil is rich in natural antioxidants (8). These antioxidants may directly react with free radicals and prevent lipid oxidation in human low-density lipoprotein. 

FIGURE 9.5 Comparison of PDA chromatograms (at 210 nm) of six different seed oil samples. TAG peaks are labeled using abbreviations of their fatty acid composition where, P is palmitic acid, S is stearic acid, O is oleic acid, L is linoleic acid, Ln is linolenic acid. (From Lee, P. J. and Gioia A. J. 2009. Lipid Techn. 21 112-115. With permission.)... 

Palombo, JD, DeMicheUe, SJ, Liu, JW, Bistrian, BR and Huang, YS (2(XX)) Comparison of growth and fatty acid metabolism in rats fed diets containing equal levels of y-linolenic acid from high y-Unolenic acid canola oil or borage oil. Lipids, 35, 975-981. 

Lipids. Representative fatty acid compositions of the unprocessed triglyceride oils found in the four oilseeds are given in Table 4 (see Fats and FATTY oils). Cottonseed, peanut, and sundower oils are classified as oleic—linoleic acid oils because of the high (>50%) content of these fatty acids. Although the oleic and linoleic acid content of soybean oils is high, it is distinguished from the others by a content of 4—10% of linolenic acid, and hence is called a linolenic acid oil. 

The essential fatty acids in humans are linoleic acid (C-18 2 N-6) and a-linolenic acid (C18 3 N-3). Arachidonic acid (C20 4 N-6) is also essential but can be synthesized from linoleic acid. Administration of 2% to 4% of total daily calories as linoleic acid should be adequate to prevent essential fatty acid deficiency in adults (e.g., infusion of 500 mL of 20% intravenous lipid emulsion once weekly).7 Biochemical evidence of essential fatty acid deficiency can develop in about 2 to 4 weeks in adult patients receiving lipid-free PN, and clinical manifestations generally appear after an additional... 

The alcohol moiety is produced in a different manner from that of the acid moiety. The alcohol moiety resembles the plant hormone jasmonic acid (JA) (26) generated from linolenoyl moiety of lipids via (13,S )-hydroperoxy-linolenic acid (22), (12.13,S )-epoxylinolenic acid (23), and 12-oxo-cis-10.15-phytodienoic acid (24) by the oxylipin or octadecanoid pathway (Fig. 3) [31]. In fact, 13C was incorporated at pyrethrolone (1) carbon positions that agreed with those predicted to be labeled when the alcohol moiety is produced via the pathway (Fig. 3) [30]. Figure 3 illustrates that m-jasmone (25) is hydroxylated to yield jasmololone (4), which is then dehydrogenated to yield pyrethrolone (5). However, it has not yet been determined if this is actually the case. 

The amount of TBA reactant can be converted into moles of malondialdehyde by the extinction coefficient of 155 mM cm ozone (22), and the yield of this reaction, or ratio of malondialdehyde/ozone taken-up, is shown in Figure 9. Notice that the yield for ozone-treated linolenic acid varies with time of reaction from about 3% to over 30%. These results differ from those for lipid peroxidation reactions which also give rise to malondialdehyde but have yields of 2-5% (23). 

Figure D1.6.3 TLC-FID separation of a range of standard lipids. The mobile phase was 91 6 3 1 (v/v/v/v) hexane/ethyl acetate/diethyl ether/formic acid. Time refers to scanning time of the Chromarod. Abbreviations CE, cholesterol ester CHO, cholesterol DG, 1,2-diglyceride 1,3-DG, 1,3-diglyceride FFAU, highly unsaturated free fatty acid FFAS, less unsaturated free fatty acid MG, 1-monoglyceride PL, phosphatidylcholine TGU, highly unsaturated triglyceride TGS, saturated triglyceride. Tripalmitin and palmitic acid were used to complement trilinolenin and linolenic acid. Reproduced from Ackman and Heras (1997) with permission from AOCS Press.

Ferrier, L., Caston, L., Leeson, S., Squires, J., Weaver, B., and Holub, B. 1995. a-Linolenic acid- and docosahexaenoic acid-enriched eggs from hens fed flaxseed Influence on blood lipids and platelet phospholipid fatty acids in humans. Am J. Clin Nutr. 62, 81-86. 

For example, the LIFDI mass spectrum of biodiesel from oilseed rape revealed methyl esters of long-chain fatty acids as typical plant lipid constituents (Figure 14.3). The most prominent signal originated from the methyl ester of oleic acid (Ci i, m/z 296.4), accounting to 42.6% of the TII, followed by the methyl esters of linoleic acid (Ciga,m/z 294.4,23.8%), linolenic acid (Cm-,m/z 292.4,4.4%), stearic acid (Ci8 o, m/z 298.5, 2.8%), palmitic acid (Ci6 0, m/z 270.4, 1.4%), and gondoic acid (C2o i,... 

In contrast, the hemolymph of females of the arctiid moth Spilosoma imparilis were found to contain significant levels of the polyunsaturated hydrocarbons corresponding to the epoxide pheromone components produced by this species (Wei el al., 2003). In a biosynthetic study with the arctiid Syntomoides imaon, the pheromone of which consists of a blend of 3Z,6Z,9Z-21 H and 1,3Z,6Z,9Z-21 H (Matsuoka el al., 2008), the lipids extracted from oenocytes and peripheral fat bodies associated with the abdominal integument contained both (llZ,14Z,17Z)-eicosa-ll,14,17-trienoic acid and (13Z,16Z,19Z)-docosa-13,16,19-trienoic acid, the intermediates predicted by elongation of linolenic acid by one or two cycles of 2-carbon chain extension (Ando et al., 2008). The latter acid is likely to be the direct biosynthetic precursor to 3Z,6Z,9Z-21 H (Ando et al., 2008). 

The net result of these processes is that the fatty acids in the mammary gland, which originate from the dietary lipids, consist of substantial quantities of 16 0, 18 0 and oleic acid, small amounts of linoleic and linolenic acids, and limited quantities of other monoenoic and dienoic fatty acids such as llt-18 l and 9c, llt-18 2. 

This group of compounds is formed from the lipid fraction of the juice, through the sequential action of several enzymes. In Fig. 4.2. the mechanism described by Crouzet (1986) for the formation of cis-3- and tran5 -2-hexanal and their corresponding alcohol is shown. Linolenic acid is a common constituent of grape juice. Through the action of a lipoxygenase enzyme, linolenic acid is transformed... 

Fatty acids are especially important and ubiquitous lipids. Apart from their use as fuel, they may be used in the synthesis of many other kinds of molecules. A fatty acid is a hydrocarbon chain with a terminal —COOH group. Usually, fatty acids contain between 14 and 25 carbons, 16 and 18 being most common. Unsaturated fatty acids are those that contain double bonds between some carbon atoms. Saturated fatty acids contain only single bonds. Palmitic acid (16) and stearic acid (Cl8) are particularly common saturated fatty acids in humans. Linoleic acid (Cl8), linolenic acid (Cl8) and arachidonic acid (C20) are common polyunsaturated fatty acids ( poly meaning more than one double bond). The number of carbons typically is even, reflecting the fact that fatty acid chains are built up (and broken down) in units of 2 carbon atoms at a time. 

Although common in animal systems, the A6 desamrase is less apparent in the plant world, although it must operate in the production of y-linolenic acid (6, 9, 12-18 3) from linoleate and of stearidonic acid (6, 9, 12, 15-18 4) from a-linole-nate. The C20 and C22 polyenes that characterize animal systems and particularly fish lipids either do not exist in plant systems or are exceedingly rare. The production of important acids such as arachidonic (5, 8, 11, 14-20 4), eicosapentaenoic (5, 8, 11, 14, 17-20 5), and docosahexaenoic (4, 7, 10, 13, 16, 19-22 6) in plant systems is a challenge for plant geneticists (6). 

Evidence for this process has been obtained in systems of charged micelles prepared from linolenic acid (48) and by chemiluminescence in very early stages of lipid oxidation in oils and a variety of foods (49). 

That lipid alkoxyl radicals recombine (Reaction 71) at diffusion controlled rates (k= 10 M s ) (198, 305) probably accounts for the presence of low levels of peroxides even under mild conditions and low levels of oxidation. In one study, oxidation of linoleic acid at 30°C gave —C—O—O—C— dimers. Reactions 71-73 were found in linolenic acid oxidized under mild conditions to PV 585 this increased to > 50% at PV 4000 and to > 75% after heating to 40°C (276). Alkoxyl radicals from hydroperoxyepidioxides heated at 40°C generated > 90% dimers (276). 

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