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Fatty acid

DATA No : DFA0191 INFORMANT : Tetsuyuki Kobayashi

NAME : cis-9, cis-12, cis-15-Octadecatrienoic acid

COMMON NAME: a-Linolenic acid
SYMBOL: aLnA / C18:3n-3 / C18:3w3 / aLnn
FORMULA: C18H30O2 MOL.WT (average) : 278.430

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Dietary a-linolenic acid can be further elongated and desaturated to form the long-chain n-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosapentaenoic acid (DHA), which are uniquely rich in neural membranes of retina and brain in mammals. It has been reported that n-3 fatty acid deficiency produces reduced learning ability(Ref. 2005), impaired vision, abnormal electroretinogram(Ref. 2006/2007) and polydipsia(Ref. 2008). Dietary fat manipulation of perilla oil rich in a-linolenic acid reduces colonic damage in experimental Crohn's disease (Ref. 2015/2016).
MELTING POINT:-11.3 to -11degC

BOILING POINT:125degC at 0.05 mmHg

REFRACTIVE INDEX:1.4678 at 50degC


DENSITY:d4-20 0.9164

SOLUBILITY:soluble in acetone, ethanol, ether and petroleum ether.(Ref. 0400)




Gas liquid chromatogram
[Chromatogram 0001] (provided by Dr. Akiko Horiuchi).
Linseed, perilla, and hemp oils; drying oils.

Linoleic acid (18:2n-6) is synthesized from oleic acid (18:1n-9) by desaturation of D12-desaturase, and a-linolenic acid (18:3n-3) is formed from linoleic acid by desaturation reaction of D15-desaturase. Since both D12- and 15-desaturases are present in plant cells, a-linolenic acid is synthesized in plants, and relatively enriched in leaves (photosynthetic tissues). On the other hand, these desaturases are not present in animal cells, neither linoleic nor a-linolenic acid is biosynthesized in animal cells in vivo. When ingested by animals, a-linolenic acid is desaturated, elongated and chain-shortened to form eicosapantaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA)(Ref. 2001/2002). No interconversion between the n-6 and n-3 series in mammals.
Nutritionally, it is important to note that different foods contain different proportions of n-6/n-3 and therefore the n-6/n-3 ratio in tissue lipids change significantly depending on the choice of foods. Although plants synthesize and store linoleic acid and a-linolenic acid as well as saturated and monounsaturated fatty acids in grains, the proportions of these fatty acids in different vegetable oils differ greatly. Safflower and sunflower oil contain high levels of linoleate, while perilla and linseed oil are rich in a-linolenic acid.


AUTHOR:Powell, R. G., et al. (1965)Abstr. Meet. Amer. Oil Chem. Soc.
VOL: PAGE : 32 - (1965)

AUTHOR:Voss, A., Reinhart, M., Sankarappa, S., and Sprecher, H.
TITLE:The metabolism of 7,10,13,16,19-docosapentaenoic acid to 4,7,10,13,16,19-docosahexaenoic acid in rat liver is independent of a 4-desaturase PubMed ID:1834642
JOURNAL:J Biol Chem.
VOL:266 PAGE : 19995-20000 (1991)

AUTHOR:Moore, S. A., Hurt, E., Yoder, E., Sprecher, H., and Spector, A. A.
TITLE:Docosahexaenoic acid synthesis in human skin fibroblasts involves peroxisomal retroconversion of tetracosahexaenoic acid PubMed ID:8656081
JOURNAL:J Lipid Res.
VOL:36 PAGE : 2433-2443 (1995)

AUTHOR:Yamamoto, N., Saitoh, M., Moriuchi, A., Nomura, M., and Okuyama, H.
TITLE:Effect of dietary alpha-linolenate/linoleate balance on brain lipid compositions and learning ability of rats PubMed ID:2883248
JOURNAL:J Lipid Res.
VOL:28 PAGE : 144-151 (1987)

AUTHOR:Neuringer, M., Connor, W. E., Van Petten, C., and Barstad, L.
TITLE:Dietary omega-3 fatty acid deficiency and visual loss in infant rhesus monkeys PubMed ID:6317716
JOURNAL:J Clin Invest.
VOL:73 PAGE : 272-276 (1984)

AUTHOR:Neuringer, M., Connor, W. E., Lin, D. S., Barstad, L., and Luck, S.
TITLE:Biochemical and functional effects of prenatal and postnatal omega 3 fatty acid deficiency on retina and brain in rhesus monkeys PubMed ID:3459166
JOURNAL:Proc Natl Acad Sci U S A.
VOL:83 PAGE : 4021-4025 (1986)

AUTHOR:Reisbick, S., Neuringer, M., Hasnain, R., and Connor, W. E.
TITLE:Polydipsia in rhesus monkeys deficient in omega-3 fatty acids PubMed ID:2159161
JOURNAL:Physiol Behav.
VOL:47 PAGE : 315-323 (1990)

AUTHOR:Shoda, R., Matsueda, K., Yamato, S., and Umeda, N.
TITLE:Therapeutic efficacy of N-3 polyunsaturated fatty acid in experimental Crohn's disease PubMed ID:8563904
JOURNAL:J Gastroenterol.
VOL:30 Suppl 8 PAGE : 98-101 (1995)

AUTHOR:Shoda, R., Matsueda, K., Yamato, S., and Umeda, N.
TITLE:Epidemiologic analysisof Crohn disease in Japan: increased dietary intake of n-6 polyunsaturated fatty acids and animal protein relates to the increased incidence of Crohn disease in Japan PubMed ID:8615358
JOURNAL:Am J Clin Nutr.
VOL:63 PAGE : 741-745 (1996)

Last updated June 19, 2007. Copyright © 1989-2007 Japanese Conference on the Biochemistry of Lipids (JCBL). All rights reserved.