Therans-3-enoic acids ofAster alpinus andArctium minus seed oils

Thetrans-3-enoic acids ofAster alpinus (dwarf aster, rock aster) andArctium minus (burdock) seed oils have been isolated and characterized.Arctium seed oil containstrans-3,cis-9,cis-12-octadecatrienoic acid (9.9%), andAster oil containstrans-3-hexadecenoic (7.1%),rans-3-octadecenoic (1.9%),trans-3,cis-9-octadecadienoic (3.0%),a ndtrans-3,cis-9,cis-12-octadecatrienoic (13.7%) acids.Aster oil also has an epoxy acid as a minor constituent (ca. 2.0%), which has been identified ascis-9,10-epoxy-cis-12-octadecenoic acid.     

Oxygenated fatty acids of oil from sunflower seeds after prolonged storage

Chemical analysis of a number of sunflower (Helianthus annuus) seed oil samples revealed a low and variable percentage of hydrogen bromide-reactive material. To characterize the compounds responsible for this reactivity, oil was extracted from selected introductions from Uruguay, Turkey, and Yugoslavia that had been subjected to prolonged storage. Two epoxy fatty acids and two conjugated dienolic acids were isolated from the methyl esters derived from these sunflower seed oils by using a combination of column chromatography and countercurrent distribution. The epoxy acids arecis-9,10-epoxystearic acid (0.5%) andcis-9,10-epoxy-cis-12-octadecenoic (coronaric) acid (2.2%). Characterization of the dienols revealed that they are 9-hydroxy-trans-10,cis-12-octadecadienoic acid (1.2%) and 13-hydroxy-cis-9,trans-11-octadecadienoic acid (1.3%). Fresher seed of some of these introductions contained less of the oxygenated components. Oil from recently produced seed of selected high-oil Russian sunflower varieties, including some currently grown in the United States, contained no more than trace amounts of oxygenated acids. Though the relative contributions of genetic and environmental factors toward genesis of oxygenated acids are not established, increase of those acids in some sunflower lines as a result of storage has been demonstrated. Presented at the AOCS-AACC Joint Meeting, Washington, D. C., April 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Homolytic decomposition of linoleic acid hydroperoxide: Identification of fatty acid products

An isomeric mixture of linoleic acid hydroperoxides, 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid (79%) and 9-hydroperoxy-cis-12,trans-10-octadecadienoic acid (21%), was decomposed homolytically by Fe(II) in an ethanol-water solution. In one series of experiments, the hydroperoxides were decomposed by catalytic concentrations of Fe(II). The 10⁻⁵ M Fe(III) used to initiate the decomposition was kept reduced as Fe(II) by a high concentration of cysteine added to the reaction in molar excess of the hydroperoxides. Nine different monomeric (no detectable dimeric) fatty acids were identified from the reaction. Analyses of these fatty acids revealed that they were mixtures of positional isomers identified as follows: (I) 13-oxo-trans,trans-(andcis,trans-) 9,11-octadecadienoic and 9-oxo-trans,trans- (andcis,trans-) 10,12-octadecadienoic acids; (II) 13-oxo-trans-9,10-epoxy-trans-11-octadecenoic and 9-oxo-trans-12, 13-epoxy-trans-10-octadecenoic acids; (III) 13-oxo-cis-9,10-epoxy-trans-11-octadecenoic and 9-oxo-cis-12, 13-epoxy-trans-10-octadecenoic acids; (IV) 13-hydroxy-9,11-octadecadienoic and 9-hydroxy-10,12-octadecadienoic acids; (V) 11-hydroxy-trans-12, 13-epoxy-cis-9-octadecenoic and 11-hydroxy-trans-9, 10-epoxy-cis-12-octadecenoic acids; (VI) 11-hydroxy-trans-12, 13-epoxy-trans-9-octadecenoic and 11-hydroxy-trans-9,10-epoxy-trans-12-octadecenoic acids; (VII) 13-oxo-9-hydroxy-trans-10-octadecenoic acids; (VIII) isomeric mixtures of 9, 12, 13-dihydroxyethoxy-trans-10-octadecenoic and 9, 10, 13-dihydroxyethoxy-trans-11-octadecenoic acids; and (IX) 9, 12, 13-trihydroxy-trans-10-octadecenoic and 9, 10, 13-trihydroxy-trans-11-octadecenoic acids. In another experiment, equimolar amounts of Fe(II) and hydroperoxide were reacted in the absence of cysteine. A large proportion of dimeric fatty acids and a smaller amount of monomeric fatty acids resulted. The monomeric fatty acids were examined by gas liquid chromatography-mass spectroscopy. Spectra indicated that the monomers were largely similar to those produced by the Fe(III)-cysteine reaction. Presented in part at the American Chemical Society Meeting, Los Angeles, March 1974. ARS, USDA.     

Rapid transesterification and mass spectrometric approach to seed oil analysis

Fatty acid composition of seed oil is determined in less than one hr using a quantitative one-vial technique. The method of analysis requires alcoholic solutions of sodium methoxide mild enough for epoxy and polyunsaturated oils. Separation and characterization of component fatty acids were accomplished by high resolution gas chromatography-mass spectrometry. Using this method,Vernonia galamensis seed oil is shown to contain 79–80% vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid.Amaranthus cruentus, a West African vegetable crop, is shown to contain 17.3% palmitic acid, 3.2% stearic acid, 22.7% oleic acid, 54.7% linoleic acid and 2.1% linolenic acid.     

OxygenatedTrans-3-olefinic acids in aStenachaenium seed oil

Interesting differences were found in oils from two samples ofStenachaenium macrocephalum (Compositae) seed with dissimilar storage histories. One contained significant amounts of epoxy acids (6.5%) and hydroxy conjugated dienoic acids (5.6%), but the other contained no more than 1% of these oxygenated acids. Characterization of components in the former oil established that the principal epoxy acid (4.0%) is the previously unknowncis-9, 10-epoxy-trans-3,cis-12-octadecadienoic acid. The conjugated dienols include two additional new acids with Δ3 unsaturation (2.5%): 9-hydroxy-trans-3,-trans-10,cis-12-octadecatrienoic and 13-hydroxy-trans-3,cis-9,trans-11-octadecatrienoic acoids. The nonoxygenated acids, except for the large amount (40%) oftrans-3,cis-9,cis-12-octadecatrienoic, are those that commonly occur in seed oils. Presented at the AOCS Meeting, San Francisco, April 1969. No. Utiliz. Res. Dev. Div., ARS, USDA.     

cis-5,cis-9,cis-12-octadecatrienoic and some unusual oxygenated acids inXeranthemum annuum seed oil

Seed oil ofXeranthemum annuum (family Compositae) contains a number of unusual fatty acids in addition to palmitic, stearic, oleic, linoleic and linolenic. These acids includecis-5,cis-9,cis-12-octadecatrienoic, 5%;cis-9-l,10-l-epoxyoctadecanoic, 3%;cis-9-l,10-l-epoxy-cis-12-octadecenoic (coronaric), 8%; andcis-12-d,13-d-epoxy-cis-9-octadecenoic (vernolic), 2%; as well as a mixture of two hydroxy acids, 11%. The absolute configurations of the two 9,10-epoxy acids are established for the first time. Presented in part at the AOCS Meeting in Cincinnati, October 1965. No. Utiliz. Res. Dev. Div., ARS, USDA.     

High-performance liquid chromatography of the triacylglycerols ofVernonia galamensis andCrepis alpina seed oils

The triacylglycerols ofVernonia galamensis andCrepis alpina seed oils were characterized because these oils have high concentrations of vernolic (cis-12,13-epoxy-cis-9-octadecenoic) and crepenynic (cis-9-octadecen-12-ynoic) acids, respectively. The triacylglycerols were separated from other components of crude oils by solid-phase extraction, followed by resolution and quantitation of the individual triacylglycerols by reversed-phase high-performance liquid chromatography with an acetonitrile/methylene chloride gradient and flame-ionization detection. Isolated triacylglycerols were characterized by proton and carbon nuclear magnetic resonance and by capillary gas chromatography of their fatty acid methyl esters. The locations of the fatty acids on the glycerol moieties in the oils were obtained by lipolysis. TheVernonia galamensis oil contained 50% trivernoloyl and 21% divernoloyllinoleoyl glycerols along with 20% triacylglycerols with one vernolic and two other fatty acids. TheCrepis alpina oil contained 36% tricrepenynoyl and 33% dicrepenynoyllinoleoyl glycerols, 17% triacylglycerols with two crepenynic and one other fatty acid and 7% triacylglycerols with one crepenynic acid and two other fatty acids. Vernolic acid was found at both the 1(3)- and 2-glycerol carbons but was more abundant at the 1,(3)-position in theVernonia galamensis oil. Crepenynic acid was found at both glycerol carbon positions but was more abundant at the 2-position in theCrepis alpina oil. Visiting scientist from Technical Research Institute, Snow Brand Milk Company, Ltd., Saitana, Japan.     

Optically active trihydroxy acids ofChamaepeuce seed oils

Two trihydroxy acids have been isolated fromChamaepeuce afra (Jacq.) DC, seed oil and identified as (+)-threo-9,10,18-trihydroxyoctadecanoic (phloionolic) acid (9%) and (+)-threo-9,10-,18-trihydroxy-cis-12-octadecenoic acid (14%). The unsaturated acid has not previously been found in nature. Nuclear magnetic resonance, infrared, thin-layer chromatography, optical rotation, and identification of the oxidative cleavage products show that these two trihydroxy components have the structures indicated.Chamaepeuce hispanica DC. seed oil and the seed oil of an unidentifiedChamaepeuce species apparently contain these same two acids but in different proportions fromC. afra oil. Presented at the AOCS Meeting, Philadelphia, October 1966. No. Utiliz, Res Dev. Div., ARS, USDA.     

γ-Linolenic acid inAcer seed oils

The octadecatrienoic acids inAcer negundo L. (maple family) seed oil include both 9,12,15- (1%) and 6.9,12-(7%) isomers. The chief monoenoic acids identified were 9-octadecenoic (21%), 11-eicosenoic (7%), 13-docosenoic (15%), and 15-tetracosenoic (7%). Also present is a considerable amount of 9,12-octadecadienoic acid. Investigation of ten other Aceraceae revealed their seed oils to have a similar fatty acid composition.     

Vernonia galamensis: A rich source of epoxy acid

A percolation extraction ofVernonia galamensis seed, affording 38.6% of crude vernonia oil is described. The dark colored crude oil was degummed with water, treated with activated charcoal and bleached with a neutral agent, to give a light colored oil (Lovibond: 0.9 red, 3.5 yellow). Gas chromatographic/mass spectrometric analysis of the refined oil indicates a relative fatty acid composition of 79–81% vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid, 11–12% linoleic acid, 4–6% oleic acid, 2–3% stearic acid, 2–4% palmitic acid, and a trace amount of arachidic acid.     

Occurrence ofCis-6-hexadecenoic acid as the major component ofThunbergia alata seed oil

An unusual series of monoenoic fatty acids constitutes about 85% of the total acids in seed oil fromThunbergia alata. The major component in the oil,cis-6-hexadecenoic acid (82%), is accompanied by the homologous 4-tetradecenoic (ca. 0.2%) and 8-octadecenoic (1.8%) acids. Another homologous series is represented by 5-tetradecenoic (ca. 0.2%), 7-hexadecenoic (1.8%) and the familiar 9-octadecenoic (4.4%) acids. Traces (<0.1%) of three other acids, 6-tetradecenoic and 10- and 11-octadecenoic, are also present along with palmitic (5.8%), stearic (0.6%) and linoleic (2.2%) acids. Some of the monoenoic acids have not previously been known to occur in seed oils. Presented at the Fifth Great Lakes Regional Meeting of the American Chemical Society, Peoria, Illinois, 1971. No. Market. Nutr. Res. Div., ARS, USDA.     

Lack of regioselectivity in formation of oxohydroxyoctadecenoic acids from the 9- or 13-hydroperoxide of linoleic acid

Either 9-hydroperoxy-trans-10,cis-12-octadecadienoic acid or 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid was treated with the catalyst, cysteine-FeCl₃, in the presence of oxygen. Oxohydroxyoctadecenoic acids were among the many products formed as a result of hydroperoxide decomposition. A mixture of 9(13)-oxo-13(9)-hydroxy-trans-11(10)-octadecenoic acids (δ-ketols) was produced from either isomeric hydroperoxide. The formation of isomeric δ-ketols from 9-hydroxy-trans-12,13-epoxy-trans-10-octadecenoic acid (epoxyol), a known product of 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid decomposition, implies that the epoxyol is an intermediate. The mechanism was elucidated by the facile conversion of the epoxyol (methyl ester_ to methyl 9(13)-oxo-13(9)-hydroxy-trans-11(10)-octadecenoates with a Lewis acid, BF₃-etherate. Presented at the 14th World Congress, International Society for Fat Research, Brighton, U.K., September 17–22, 1978. The mention of firm names or trade products does not imply that they are endorsed or recomended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

TheTrans-6 fatty acids ofPicramnia sellowii seed oil

The C₁₈ monoenoic acids inPicramnia sellowii Planch. seed oil include bothcis-andtrans-6-octadecenoic acids, as well as oleic acid. The hexadecenoic acids are also thecis- andtrans-Δ6-isomers, and the eicosenoic acids have Δ6-unsaturation of undetermined geometric configuration. The C₁₈ polyenoic acids detected are 9,12- and 6,9-octadecadienoic and 9,12,15- and 6,9,12-octadecatrienoic acids. Partial investigation of another species,P. pentandra Sw., revealed its oil to have a similar fatty acid composition. Presented in part at AOCS Meeting, New York, October 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Analyses of fatty acid isomers in two commercially hydrogenated soybean oils

A conventional shortening and a hydrogenated winterized oil have been investigated to determine their composition of natural and isomeric fatty acids. Two solvent systems were applied in countercurrent distributions: the acetonitrile pentane-hexane system for separation of monoenoates from dienoates and the methanolic silver nitrate pentane-hexane system for separation of geometric isomers. Whilecis andtrans monoenoates were well resolved, the separation ofcis,cis fromcis,trans dienoates was complicated by the presence of positional isomers. The fractions isolated were oxidatively cleaved, and the esters of the resultant acids were quantitatively analyzed by gas-liquid chromatography. Although the amounts of saturated components of the two fat products were similar, the percentage oftrans isomers of the shortening was more than twice that of the winterized oil. The amount of oleic acid (cis-9-octadecenoic) was 19.6% for the shortening and 25.4% for the winterized oil. The shortening contained 13.3% linoleic acid (cis,cis-9,12-octadecadienoic), whereas the winterized oil contained 30% linoleic acid. Although our primary interest was in the estimation ofcis-9-octadecenoic andcis,cis-9,12-octadecadienoic acids, the completeness of cleavage data makes it possible to estimate all geometric and positional monoenoate and dienoate isomers in the two fat products. Presented at AOCS meeting in New Orleans, La., May, 1962. A laboratory of the No. Utiliz. Res. and Dev. Div., ARS, USDA.     

Lactobacillic and methyl-branched olefinic acids inByrsocarpus coccineus seed oil

A detailed investigation of the seed oil ofByrsocarpus coccineus Schum. and Thonn. has disclosedcis-11,12-methyleneoctadecanoic (lactobacillic) (13%) and two branched octadecenoic acids (0.1%). Other fatty acids in the oil are those normally associated with seed lipids except for an unusually high proportion (12%) ofcis-11-octadecenoic acid. Lactobacillic acid has long been known as a constituent of certain bacterial lipids, but this is the first report of its presence in a seed oil. The branched olefinic acids have not heretofore been found to occur in plants. Mention of firm names or trade products does not imply endorsement or recommendation by the Department of Agriculture over other firms or similar products not mentioned.     

Minor components ofLesquerella fendleri seed oil

Routine analysis of fatty ester fractions ofLesquerella fendleri oil suggested the presence of epoxy compounds and other minor components. By a combination of open silica column and high performance liquid chromatography (HPLC) fractionations of the methyl esters prepared from the oil, these constitutents were isolated and then characterized by thin-layer chromatography-mass spectrometry (GC-MS—electron ionization, EI, and chemical ionization, CI) and nuclear magnetic resonance (NMR—¹H and¹³C). Three epoxy acids, 15,16-epoxy-9,12-octadecadienoic, 9,10-epoxy-12-octadecenoic and 9,10-epoxy-octadecanoic, were found. Hydroxy acids present included a C-22 homologue of lesquerolic acid (16-hydroxy-12-docosenoic acid) and 14,15-dihydroxy-tricosanoic acid. Other minor ocmponents included four sterols, brassicasterol, campesterol, β-sitosterol and stigmasterol, and a series of saturated and unsaturated fatty acids up to C30. Visiting postdoctoral scientist sponsored by the government of India.     

Search for new industrial oils. XII. Fifty-eight euphorbiaceae oils,including one rich in vernolic acid

Seed oil ofEuphorbia lagascae Spreng. contains 57% ofcis-12,13-epoxy-cis-9-octadecenoic (vernolic) acid. The amt of trivernolin in the glycerides of this species indicates random or restricted random distribution of the vernolic acid. Seed from 57 additional species in the Euphorbiaceae were analyzed for oil and protein contents and also for fatty acid composition of the oils. Iodine values (I.V.) of the oils ranged from 87–221. Among these oils, samples were encountered with as much as 76% linolenic, 77% linoleic or 84% oleic acid. Presented at the AOCS in New Orleans, 1964. A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, USDA. ARS, USDA.     

Cis-5-monoenoic fatty acids ofCarlina (Compositae) seed oils

Seed oils ofCarlina corymbosa L. andC. acaulis L. containcis-5-octadecenoic acid as a major fatty acid (21–24%). This acid has not been previously reported as a constituent of Compositate seed oils. The predominant fatty acid in theCarlina oils is linoleic (50–52%); lesser amounts (≦10% each) of palmitic, stearic and oleic acids are also present. The oil ofC. acaulis has almost 2% ofcis-5-hexadecenoic acid;C. corymbosa oil includes minor amounts of some oxygenated fatty acids. Presented at the AOCS Meeting, New York, October 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

New sources of 9-d-hydroxy-cis-12-octadecenoic acid

9-d-Hydroxy-cis-12-octadecenoic acid has been isolated from 3 seed oils of the family Apocynaceae:Holarrhena antidysenterica (73%),Nerium oleander (11%) andNerium indicum (8%). The known occurrence of this acid was previously limited to the genusStrophanthus (9–15%). A mixture of unusual tetra-acid glycerides was isolated fromN. oleander oil by thin layer chromatography. Pancreatic lipase hydrolysis of the glyceride mixture showed that 9-d-acetoxy-cis-12-octadecenoic acid is esterified exclusively at an α-glycerol position and that normal fatty acids occupy the remaining 2 glycerol positions. A portion of the hydroxy acid inN. indicum oil was also acetylated, however, no acetate was found in eitherH. antidysenterica orStrophanthus hispidus oils. Presented at the AOCS Meeting, San Francisco, April, 1969. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Chemical epoxidation of a natural unsaturated epoxy seed oil fromVernonia galamensis and a look at epoxy oil markets

Since 1963, production of all epoxy esters has ranged from 60 to 150 million lb annually, a steady 7% of the 1 to 2 billion lb of annual plasticizer production. Growth rates in production averaged 4.3% for all plasticizers, 3.8% for all epoxy esters and 5.0% for epoxidized soybean oil (ESBO). ESBO accounted for 70–76% of total epoxy ester production (1963–1982). The natural liquid epoxy oil fromVernonia galamensis seed, with oxirane value (4.1%) and viscosity (100 cps) similar to some commercial epoxy fatty esters but with molecular weight similar to epoxidized vegetable oils, combines some of the properties of both commercial types. Chemical epoxidation ofVernonia oil raises the oxirane content to 8.2, intermediate between ESBO and epoxidized linseed oil (ELSO), while consuming less of the costly epoxidizing reagents. Epoxidation proceeds in stepwise fashion through partially epoxidized products, which are converted to final product. Since the major fatty components ofVernonia oil arecis-12,13-epoxy-9-octadecenoic (75%) and linoleic (13%) acids, further epoxidation produces fatty acids that are specifically epoxidized at the 9,10- and 12,13-positions, and the major product has 6 epoxy units per triglyceride molecule. The resulting mixture of products has compositional and physical properties distinctly different from commercial samples of ESBO and ELSO.