Conjugated octadecatrienoic acids

Momordica balsamina L. [inkakha, bitter gourd] (Cucurbitaceae) aerial parts are eaten as a vegetable for hypertension and diabetes 18). The leaf contains alkaloids, flavonoids, glycosides and polyphenols 18). The seed oil contains two conjugated octadecatrienoic acids 19). The plant also possesses antiplasmodic, analgesic and sedative properties which have been demonstrated in rodents (20). 

Nugteren, D.H., and Christ-Hazelhof, E. (1987) Naturally Occurring Conjugated Octadecatrienoic Acids Are Strong Inhibitors of Prostaglandin Biosynthesis, Prostaglandins 33,403-417. 

Takagi, T., and Itabashi, Y. (1981) Occurrence of Mixtures of Geometrical Isomers of Conjugated Octadecatrienoic Acids in Some Seed Oils Analysis by Open-Tubular Gas Liquid Chromatography and High Performance Liquid Chromatography, Lipids 16,546-551. 

Seven conjugated octadecatrienoic acids have been recognized as natural compounds including three 8,10,12-trienes and four 9,11,13-trienes. Detailed configuration, trivial names and some indication of... 

Conjugated octadecatrienoic acids are available in tung oil (a-eleostearic acid, 70-80%, Section 3.3.39), in oiticia oil (licanic acid, 80%, Section 3.3.22) and... 

Potential for Producing Oils Containing Conjugated Octadecatrienoic Acids... 

Z,Z,Z,)-9,12,15-octadecatrienoic acid). Fish oils contain esters of eicosanoic and docosanoic acids with four to six double bonds separated by single methylene groups, eg, (i7//-Z)-4,7,10,13,16,19-docosahexaenoic acid [6217-54-5] in menhaden oil (4). The fatty acid with conjugated double bonds in tung oil is a-eleostearic acid [506-23-0] ((F,Z,F)-9,ll,13-octadecatrienoic acid) the predominant fatty acid in oiticica oil is licanic acid [17699-20-6] (4-oxo-(F,Z,F)-9,ll,13-octadecatrienoic acid). In all oils, other fatty acids including palmitic acid [57-10-3] (hexadecanoic acid), stearic acid [57-11-4] (octadecanoic acid), and oleic acid [112-80-1] ((Z)-9-octadecenoic acid) also are present. 

Hamberg, M. 1992. Metabolism of 6,9,12-octadecatrienoic acid in the red alga Litho-thamnion corallioides mechanism of formation of a conjugated tetraenes fatty acid. Biochem. Biophys. Res. Comm., 188,1220-1227. 

Fatty acids with two or more conjugated double bonds are found in some plants and animals. In tissues of ruminant animals (and, hence, in meat and dairy products), fatty acids with conjugated diene system were detected as intermediates or by-products in the biohydrogenation of linoleic acid by microorganisms in the rumen. The main isomer, 9-cis, ll-fran -octadecadienoic acid, may account for up to 1% of the total fatty acids of milk fat. 9-cis, ll-fran5-15-cw-octadecatrienoic acid, derived from a-linolenic acid, is present in ruminant tissues only in trace levels. This fatty acid has been shown to have several medical properties, especially anti-cancer and anti-atherosclerosis effects. 

Calendula oil. Extract of the fat oil from flowers of marigold Calendula officinalis, Asteraceae) for pharmaceutical and cosmetic uses, e. g., anti-inflammatory ointments. C. for technical uses is also obtained from marigold seeds. The seed oil contains large amounts (ca. 60%) of esterified calend(ul)ic acid [(8 ,10 ,12Z)-octadecatrienoic acid, CuHjqOj, Mr 278.44, mp. 40-40.5 °C]. The conjugated double bonds of calendulic acid are readily oxidized and polymerized so that C. can also serve as starting material for paints and varnishes. 

The infrared and ultraviolet spectra of a product of the biohydrogenation of linolenic acid in Butyrivibriofibrisolvens displayed a conjugated cis,trans-diene system and the product was shown to be cis-9,trans-l l,cis-15-octadecatrienoic acid (Kepler and Tove, 1967). Wilde and Dawson (1966) had found that linolenic acid was first converted to a trienoic acid in which two of the double bonds were conjugated. This was tentatively identified as either or A -octadecatrienoic acid. Since... 

Preparation of Labeled (10E,12Z) CLA Metabolites. (6Z,10 ,12Z)-[l-i4c]-Octadecatrienoic acid and (8Z,12 ,14Z)-[l- C]-eicosatrienoic add were synthesized using a series of sequential substitutions of 1,2-dichloro-ethene and a Wittig-type reaction as depicted in Figure 6.8 (Loreau, O., and Noel, J.P., unpublished data). The bromo precursors were transformed into alkenyl lithium derivatives, and carbonation with " C02 provided the labeled conjugated trienoic acids with high stereochemical purity (>95%). 

Thomasson (1953) noted that ordinary linolenic acid (9,12,16-octa-decatrienoic acid), formerly considered as possessing biopotency equal to that of linoleic acid, under certain conditions, is actually practically inactive (9%) when tested by the new bio-assay method of the author on the other hand, y-linolenic acid (6,9,12-octadecatrienoic acid) is considered to possess 100% biopotency as compared with linoleate. The conjugated trienoic acid, a-elaeostearic acid (9,11,13-octadecatrienoic acid), was reported by Burr, Burr, and Miller (1932) to be ineffective in counteracting the fat-deficiency syndrome confirmatory negative results have... 

Eleostearic Acid n CH3(CH2)3(CH=CH)3(CH2)7COOH. Ocatadeca-9,11,13-trienoic acid, ds,tranSytranSy9y 11,13-Octadecatrienoic acid. Principal constituent acid of tung oil, characterized by the presence of three conjugated double bonds. Two forms are known, namely a and P types, with mps of 49°C and 71°C, respectively. 

Double-bond Migration and Cyclization Reactions.—Linolenic acid (18 3 9cl2d5c) is converted by potassium hydroxide at 180°C or by sodium hydroxide at 220 °C, first to a conjugated trienoic acid, and then to a di-substituted cyclohexadiene (13—21 %), which is identified after aromatization with palladium-charcoal. A series of octadecatrienoic acids, when submitted to this reaction, gave the product(s) indicated in parentheses 9cl2cl5c (28 n = 3), 9/12/15/ (28 n =2,3, and 4), 9cll/13/ (28 n = 3, 4, and 5),... 

The major fatty acids present in plant-derived fatty substances are oleic acid (9-octadecenoic, C18 l), linoleic acid (9,12-octadecadienoic, C18 2) and the conjugated isomers thereof and linolenic acid (9,12,15-octadecatrienoic, C18 3) (Scheme 31.1). Their rates of oxygen absorption are 100 40 1, respectively, hence partial hydrogenation with consequent lowering of the iodine number would lead to a significant increase in oxidative stabihty, particularly when C18 3 is reduced. 

The only conjugated dienoic fatty acid isolated from plant sources (the seed oil of Chilopsis linearis) is reported to be trans-lO, trans-12-octadecadienoic acid. In contrast, fatty acids with conjugated triene systems have been detected in various plant species. Tung oil is the commercial source of the most widespread fatty acid from this group, 9-cis, W-trans, I i-trans-octadecatrienoic (a-eleostearic) acid (1, 2). 

Some plant species synthesise fatty acids with one or more double bonds of the frans-configuration (e.g. frans-9,frans-12-octadecenoic acid), with conjugated double bond systems (e.g. cis-9,trans-, trans- Z-octadecatrienoic or a-eleostearic acid), or with acetylenic bonds (e.g. octadec-c/s-9-en-12-ynoic or crepenynic acid). The natural occurrence of such fatty acids has been reviewed [71,856],... 

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