Y-Linolenic acid oils

Laakso, P (1997) Characterization of a- and y-linolenic acid oils by reversed-phase high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. J. Am. Oil Chem. Soc., 74, 1291-1300. 

The complete fatty acid compositions of some of these oils, namely low-linolenic, high-oleic acid, lauric acid and y-linolenic acid oils, are given in Table 4.2. 

Transesterification 2-ethyl-1-hexanol and rapeseed oil 9-Hydroperoxy-acid from y-linolenic acid... 

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 are several sources of y-linolenic acid including evening primrose, borage and blackcurrant oils. Indeed, the evening primrose is grown commercially for the production of y-linolenic acid. It is available in most health food shops and pharmacies. 

High-grade oil with the essential polyunsaturated fatty acids can be extracted very successfully with CO2. The physiological activity of these oils is determined by the at-6,9-double bonds, and y-linolenic acid, Ci8 3 (6c, 9c, 12c) is of particular interest. 

Evening primrose oil is rich in the essential fatty acid linoleic acid and its metabolite, y-linolenic acid. In the U.K., evening primrose oil preparations have received approval as medicines for the relief of atopic eczema and for the symptomatic treatment of breast pain. 

Table 4.6 Formation of geometrical isomers of y-linolenic acid in borage oil deodorized at different temperatures as determined by gas liquid chromatography of fatty acid isopropyl esters on a 30 m long DB-wax capillary column...

Wolff, R.L. and Sebedio, J.L. (1994) Characterization of y-linolenic acid geometrical isomers in borage oil subjected to heat treatments (deodorization). J. Am. Oil Chem. Soc., 71, 117-126. 

Hills, M. J., Kiewitt, I., and Mukherjee, K. D. 1990. Enzymatic fractionation of fatty acids enrichment of y-linolenic acid and docosahexaenoic acid by selective esterification catalyzed by lipases. /. Am. Oil Chem. Soc., 67, 561-564. 

Nagao, T., Watanabe, Y., Kobayashi, T., Sumida, M., Kishimoto, N., Fujita, T., and Shimada, Y. 2007. Enzymatic purification of dihomo-y-linolenic acid from Mortier-ella single-cell oil. J. Mol. Catal. B Enzym., 44,14-19. 

Shimada, Y., Sugihara, A., Shibahiraki, M., Fujita, H., Nakano, H., Nagao, T., Terai, T., and Tominaga, Y. 1997b. Purification of y-linolenic acid from borage oil by a two-step enzymatic method./. Am. Oil Chem. Soc., 74,1465-1470. 

Certik, M., Balteszova, L., and Sajbidor, J. 1997. Lipid formation and y-linolenic acid production by Mucorales fungi grown on sunflower oil. Lett. Appl. Microbiol., 25, 101-105. 

The list of natural fatty acids exceeds 1000, but commercial interest is limited to a smaller number— perhaps around 20. Ignoring the lipid membrane, rich in ot-lino-lenic acid and present in all green tissue, the three dominant acids in the plant kingdom are palmitic, oleic, and linoleic, sometimes accompanied by stearic acid and by linolenic acid. Others, occuring in specialty oils, include myristic, lauric, erucic, hexadecenoic, petroselinic, y-linolenic acid, eleostearic and isomers, ricinoleic, and vemolic (Table 1). 

TABLE 7. Component Acids of Oils Containing y-Linolenic Acid (Typical Results,% wt). 

Hemp (Marijuana, Cannabis sativa). Hemp seed oil has an interesting fatty acid composition. One report gives the followimg values palmitic (4—9%), stearic (2-4%), oleic (8-15%), linoleic (53-60%), a-linolenic (15-25%), y-linolenic (0-5%), and stearidonic acid (0-3%). The oil is being used in cosmetic formulations (116). Evidence from a study in Finland indicates that dietary consumption of hemp seed oil leads to increased levels of y-linolenic acid in blood serum (117). The growing of hemp is banned in the United States, and therefore, hemp seed oil must be imported into that country (118-119). 

The commercial introduction of a new lipid source is not a trivial matter. Unless the oil has some specific and novel property (like oils containing y-linolenic acid, for example), it will have to compete with existing oils available in bulk at commodity prices. This exerts a number of constraints. 

Rapeseed oils still higher in lauric acid, high in erucic, palmitic, oleic, or linoleic acid, or containing Cg and Cjo acids, myristic, stearic, petroselinic, ricinoleic, vernolic, or y-linolenic acid, and wax esters in place of the normal triacylglycerols (Table 11). 

Y. S. Huang and D. E. Mills, eds., y-Linolenic Acid Metabolism and its Roles in Nutrition and Medicine, American Oil Chemists Society, Champaign, Illinois, 1996. 

An alternative route to EPA and DHA can come from elongation and further desaturation of stearidonic acid (18 4A ). Certain plants, including blackberry, borage, and evening primrose, contain up to 25% of y-linolenic acid (18 3A ) in their seed oil, with considerably smaller amounts of stearidonic acid. The y-linolenate arises from the action of a A6-desaturase on linoleate. Small amounts of co-3-desaturase present in these seeds account for the stearidonate produced. When A6-desaturase from borage was introduced into soy, plants producing up to 29% y-linolenate (precursor to arachidonate), with up to 4% stearidonate in oil, resulted (32). Further desaturation to stearidonate could be promoted with high expression of an co-3-desaturase. 

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