Stearidonic acid

Clough, P. (2001) Sources and production of specialty oils containing GLA and stearidonic acid. Lipid Technol., 13, 9-12. 

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). 

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). 

Saxifragaceae, and Scrophulariaceae. Kleiman et al. (8) investigated 29 species of family Borageniceae for the presence of GLA and tetraenoic (stearidonic acid, SDA) fatty acid. They observed 0-27% GLA, 0-56% ALA, and 0-17% SDA in seed oils from different plants in Boraginaceae. Janick et al. (9) identified 32 plants in which the content of GLA in seed oil can be more than 5% weight/weight (w/w) of total fatty acids (Table 1). The important crops that have been commercialized as sources of GLA-rich oils are discussed below. 

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. 

Eckert, H., LaVaUee, B., Schweiger, B.J., Kinney, A.J., Cahoon, E.B., and Clemente, T. (2006) Co-expression of the borage desaturase and the Arabidopsis desatu-rase results in high accumulation of stearidonic acid in the seeds of transgenic soybean. Planta 224, 1050-1057. 

Whelan, J. (2009). Dietary stearidonic acid is a long chain (n-3) polyunsaturated fatty acid with potential health benefits. J. Nutr. 139,5-10. 

Steam distillation, 3290, 3667, 3978,4090 Stearidonic acid, 1737 Steatosis, 1385 Stegobium paniceum, 4091 Stemmedine, 584 Stemona, 1175 Stemona alkaloids, 1183 Stephaniae tetrandrae, 1179 Stephania tetrandra S. Moore, 1449 Stephanine, 431 Stephanitis pyri, 4094 Stepholidine, 449 Sterculiaceae, 725 Stereocenters, 947 Stereochemistry, 3241, 3242 Stereoisomerism, 1014 Stereoisomers, 912, 2109, 3647 Stereospecific conversion, 1670 Stereospecificity, 4069 Steroidal, 412 alkaloids, 3237 lactones, 3468, 3473, 3488 Steroid hormone receptors, 3508 Steroids, 2733-2735, 2737-2741, 2746-2749, 2751, 2753, 2755-2757, 2763, 3666, 3670... 

As a A6 desaturated co-3 PUFA, stearidonic acid (SDA) is also particularly interesting, not only for aquaculture, but for human and livestock nutrition as well. In mammals, the conversion rate of SDA to EPA is around 17-33% [42-44], while the conversion of ALA to EPA is much lower at 0.2-7% [45]. The low rate of conversion of ALA to EPA is believed to be due to the inefficient A6 desaturation step thus, consumption of SDA could effectively bypass this step and support more efficient accumulation of downstream VLCPUFA. As flsh use a similar pathway for converting... 

Ruiz-lopez, N. Haslam, R. R Venegas-caleron M Larson, T. R. Graham, I. A. Napier J. A. era/. the synthesis and accumulation of stearidonic acid in transgenic plants a novel source of heart-healthy omega-3 fatty acids. Plant Biotechnol J 2009, 7 704-716. 

Yamazaki K. Fujikawa M. Hamazaki T. Yano S. Shono T comparison of the conversion rates of alpha-linolenic acid (18-3(N-3)) and stearidonic Acid (18 (N-3)) to longer polyunsaturated fatty acids in rats. Biochimica et Biophysica Acta 1992,1123, 18-26. 

James, M. J. Ursin, V. M. Cleland L.G. metabolism of stearidonic acid in human subjects comparison with the metabolism of other n-3 fatty acids. Am J Clin Nutr 2003, 77, 1140-1145. 

Harris, W. S. Lemke, S. L. Hansen, S. N. Goldstein, D. A. DiRienzo, M. A. Su H etal. stearidonic acid-enriched soybean oil increased the omega-3 index, an emerging cardiovascular risk marker. Lipids 2008, 43, 805-811. 

Miller, M. R. Nichols, P. D. Carter C. G. replacement of dietary fish oil for Atlantic salmon parr Salmo salar L.) with a stearidonic acid containing oil has no effect on omega-3 long-chain polyunsaturated fatty acid concentrations. Comp Biochem Phys B 2007,146, 197-206. 

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