Comparison of Postprandial Oleic Acid, 9<Emphasis Type="Italic">c,</Emphasis>11<Emphasis Type="Italic">t</Emphasis> CLA and 10<Emphasis Type="Italic">t,</Emphasis>12<Emphasis Type="Italic">c</Emphasis> CLA Oxidation in Healthy Moderately Overweight Subjects

Few studies report the individual effect of 9c,11t- and 10t,12c-CLA on human energy metabolism. We compared the postprandial oxidative metabolism of 9c,11t- and 10t,12c-CLA and oleic acid (9c-18:1) in 22 healthy moderately overweight volunteers. After 24 weeks supplementation with 9c,11t-, 10t,12c-CLA or 9c-18:1 (3 g/day), subjects consumed a single oral bolus of the appropriate [1-¹³C]-labeled fatty acid. 8 h post-dose, cumulative oxidation was similar for 9c-18:1 and 10t,12c (P = 0.66), but significantly higher for 9c,11t (P < 0.01).     

Oxidation kinetics for <Emphasis Type="Italic">cis</Emphasis>-9,<Emphasis Type="Italic">trans</Emphasis>-11 and <Emphasis Type="Italic">trans</Emphasis>-10,<Emphasis Type="Italic">cis</Emphasis>-12 isomers of CLA

The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.     

<Emphasis Type="Italic">9-trans,11-trans</Emphasis>-CLA: Antiproliferative and proapoptotic effects on bovine endothelial cells

Endothelial cell function can be influenced by nutrition, especially dietary FA and antioxidants. One class of dietary FA that is found in meat and dairy products derived from ruminant animals is conjugated linoleic acids (CLA). We have examined the effects of several CLA isomers on endothelial cell proliferation. 9t,11t-CLA was the only isomer that inhibited bovine arotic endothelial cell (BAEC) [³H]methylthymidine incorporation (I₅₀=35 μM), and this antiproliferative effect was time-dependent. A small decrease (20%) in cell number was observed only at the highest concentration (60 μM) tested. The 9c,11t-, 9c,11c-, 10t 12c-, and 11c,13t-CLA isomers did not exhibit any antiproliferative effects over a 5–60 μM concentration range. α-Tocopherol and BHT decreased BAEC proliferation, but pretreatment of cells with either of these antioxidants substantially attenuated the antiproliferative effect of 9t,11t-CLA. No difference in lipid peroxidation, as measured by the thiobarbituric acid assay for malondialdehyde, was observed on treatment of endothelial cells with either 9t,11t- or 9c,11t-CLA. However, a 43% increase in caspase-3 activity was observed after incubating BAEC with 9t,11t-CLA, suggesting that the antiproliferative effect of this isomer is partially due to an apoptotic pathway. In contrast to the above results with normal endothelial cells, these five CLA isomers all inhibited proliferation of the human leukemic cell line THP-1, with the 9t,11t isomer again being the most (I₅₀=60 μM) effective. These results confirm that different CLA isomers have different inhibitory potencies on the proliferation of normal and leukemic cells.     

Effect of <Emphasis Type="Italic">trans</Emphasis>8, <Emphasis Type="Italic">cis</Emphasis>10+<Emphasis Type="Italic">cis</Emphasis>9, <Emphasis Type="Italic">trans</Emphasis>11 Conjugated Linoleic Acid Mixture on Lipid Metabolism in 3T3-L1 Cells

Evidence suggests that minor isomers of conjugated linoleic acid (CLA), such as trans8, cis10 CLA, can elicit unique biological effects of their own. In order to determine the effect of a mixture of t8, c10+c9, t11 CLA isomers on selected aspects of lipid metabolism, 3T3-L1 preadipocytes were differentiated for 8 days in the presence of 100 μM linoleic acid (LA); t8, c10+c9, t11 CLA; t10, c12+c9, t11 CLA or purified c9, t11 CLA. Whereas supplementation with c9, t11 and t10, c12+c9, t11 CLA resulted in cellular triglyceride (TG) concentrations of 3.4 ± 0.26 and 1.3 ± 0.11 μg TG/μg protein, respectively (P < 0.05), TG accumulation following treatment with CLA mixture t8, c10+c9, t11 was significantly intermediate (2.5 ± 0.22 μg TG/μg protein, P < 0.05) between the two other CLA treatments. However, these effects were not attributable to an alteration of the Δ⁹ desaturation index. Adiponectin content of adipocytes treated with t8, c10+c9, t11 mixture was similar to the individual isomer c9, t11 CLA, and both the t8, c10+c9, t11 and c9, t11 CLA groups were greater (P < 0.05) than in the t10, c12+c9, t11 CLA group. Overall, these results suggest that t8, c10+c9, t11 CLA mixture affects TG accumulation in 3T3-L1 cells differently from the c9, t11 and t10, c12 isomers. Furthermore, the reductions in TG accumulation occur without adversely affecting the adiponectin content of these cells.     

Enzymatic Synthesis of Diacylglycerols Enriched with Conjugated Linoleic Acid by a Novel Lipase from <Emphasis Type="Italic">Malassezia globosa</Emphasis>

Diacylglycerols (DAG) of conjugated linoleic acid (CLA) were prepared by esterification of glycerol with fatty acids enriched with CLA (FFA–CLA, >95%) in the presence of a novel lipase from Malassezia globosa (SMG1). Lipase SMG1 is strictly specific to mono- and diacylglycerols but not triacylglycerols, which is similar to the properties of lipase from Penicillium camembertii (lipase G 50), but lipase SMG1 showed preference on the production of DAG with the reaction proceeding. Low temperature was beneficial for the conversion of FFA–CLA into acylglycerols, the degree of esterification reached 93.0% when the temperature was 5 °C. The maximum DAG content (53.4%) was achieved at 25 °C. The rate of DAG synthesis increased as the enzyme loading increased. However, at lipase amounts above 240 U/g mixtures, no significant increases in DAG concentration were observed. The molar ratio of FFA–CLA to glycerol and initial water content were optimized to be 1:3 (mol/mol) and 3%. Lipase SMG1 showed no regioselectivity because the contents of 1,3-DAG and 1,2-DAG were 43.1% and 21.2% based on total content of acylglycerols. By calculating the ratio of 9c, 11t-CLA to 10t, 12c-CLA, it was indicated that lipase SMG1 showed a little preference to 10t, 12c-CLA at the sn-1(3) position of monoacylglycerols (MAG), while no selectivity for 9c, 11t-CLA at the sn-2 position of DAG was obviously found.     

Production of MAG of CLA by esterification with dehydration at ordinary temperature using <Emphasis Type="Italic">Penicillium camembertii</Emphasis> lipase

Production of MAG with CLA using Penicillium camembertii mono- and diacylglycerol lipase (referred to as lipase) was attempted for the purpose of expanding the application of CLA. The commercial product of CLA (referred to as FFA-CLA) is a FFA mixture containing almost equal amounts of 9cis,11trans (9c,11t)-CLA and 10t,12c-CLA. Esterification of FFA-CLA with glycerol without dehydration achieved 84% esterification but produced almost equal amounts of MAG and DAG. Esterification with dehydration not only achieved a high degree of esterification but also suppressed the formation of DAG. When a mixture of FFA-CLA/glycerol (1∶2, mol/mol), 1% water, and 200 units/g-mixture of P. camembertii lipase was agitated at 30°C for 72 h with dehydration at 5 mm Hg, the degree of esterification reached 95% and the contents of MAG and DAG were 90 and 6 wt%, respectively. This reaction system may be applied to the industrial production of MAG with unstable CLA.     

Absorption and Metabolism of <Emphasis Type="Italic">cis</Emphasis>-9,<Emphasis Type="Italic">trans</Emphasis>-11-CLA and of Its Oxidation Product 9,11-Furan Fatty Acid by Caco-2 Cells

Furan fatty acids (furan-FA) can be formed by auto-oxidation of conjugated linoleic acids (CLA) and may therefore be ingested when CLA-containing foodstuff is consumed. Due to the presence of a furan ring structure, furan-FA may have toxic properties, however, these substances are toxicologically not well characterized so far. Here we show that 9,11-furan-FA, the oxidation product of the major CLA isomer cis-9,trans-11-CLA (c9,t11-CLA), is not toxic to human intestinal Caco-2 cells up to a level of 100 μM. Oil-Red-O staining indicated that 9,11-furan-FA as well as c9,t11-CLA and linoleic acid are taken up by the cells and stored in the form of triglycerides in lipid droplets. Chemical analysis of total cellular lipids revealed that 9,11-furan-FA is partially elongated probably by the enzymatic activity of cellular fatty acid elongases whereas c9,t11-CLA is partially converted to other isomers such as c9,c11-CLA or t9,t11-CLA. In the case of 9,11-furan-FA, there is no indication for any modification or activation of the furan ring system. From these results, we conclude that 9,11-furan-FA has no properties of toxicological relevance at least for Caco-2 cells which serve as a model for enterocytes of the human small intestine.     

Lipid body formation by <Emphasis Type="Italic">Thraustochytrium aureum</Emphasis> (ATCC 34304) in response to cell age

The heterotrophic marine protist, Thraustochytrium aureum produces substantial amounts of polyunsaturated fatty acids (PUFAs). In the present investigation, changes in the lipid and fatty acid profiles of T. aureum were studied according to the culture age. T. aureum was grown in artificial sea water medium for 10 days at 25 °C in shake culture condition. One to 10 day old cell samples were analyzed for cell biomass production, total lipid content, fatty acid profile and lipid body formation. In all the samples tested, total lipid production was found to be directly proportional to the dry cell weight of T. aureum. In the early phase of cell growth, cell biomass production, lipid content and glucose consumption were found to be higher. Thin layer chromatographic analysis (TLC) of lipids showed the presence of triacylglycerol (TAG; 169 mg/g, 90%), phospholipids (PL; 83 mg/g, 66%) and sterol (ST; 6 mg/g, 5%), which were recorded at maximum levels in the early growth phase of the cells. The composition of PUFAs and saturated fatty acids (SFAs) of the cell biomass and lipid class components (TAG and PL) was identified by gas chromatographic analysis (GC). In the early phase of cell growth, production of PUFAs in the total fatty acids was found to have attained maximum levels (61.3%) in which docosahexaenoic acid alone showed higher content of occurrence (99.0 mg/g in total lipid; 65.2 mg/g in TAG and 41.0 mg/g in PL). In the middle phase of cell growth, palmitic acid production was found to be higher (36.7 mg/g in total lipid; 31.3 mg/g in TAG and 12.6 mg/g in PL). Transmission electron microscopic studies of the cells showed the presence of a membrane around the lipid bodies in the early phase of cell growth. TAG and PL were actively involved in the formation of lipid bodies in the cells of T. aureum. Large-sized lipid bodies accumulated in 3 day old cells which were then fragmented into smaller bodies in the late growth phase.     

Marine lipid-based liposomes increase <Emphasis Type="Italic">in vivo</Emphasis> FA bioavailability

Liposomes made from an extract of natural marine lipids and containing a high n-3 PUFA lipid ratio were envisaged as oral route vectors for FA supplements in order to increase PUFA bioavailability. The absorption of FA in thoracic lymph duct-cannulated rats, after intragastric feeding of dietary fats in the form of liposomes or fish oil, was compared. Lipid and FA analyses were also performed on feces. Five mole percent α-tocopherol was added to fish oil and incorporated into the liposome membrane. The influence of α-tocopherol on FA lymph recovery was also investigated. In vivo, FA absorption in rats was favored by liposomes (98±1%) compared to fish oil (73±6%). In the same way, the DHA proportion in lymph was higher after liposome ingestion (78%) than after fish oil ingestion (47%). However, phospholipid (PL) concentration in lymph was not affected by the kind of dietary fat ingested, suggesting a PL regulation due to de novo TAG synthesis. The influence of the intramolecular distribution of n-3 PUFA in dietary lipids (TAG and PL) on the intramolecular FA distribution in TAG of chylomicrons was also investigated. The results obtained showed that the distribution of n-3 PUFA esterified on the sn-2 of chylomicron TAG depended on the lipid source administered. All these results correlated, at least partly, with in vitro liposome behavior under conditions that mimic those of the gastrointestinal tract. As a whole, this study pointed out that marine PL may constitute an attractive material for the development of liposomes as oral PUFA supplements.     

Total Lipids of Sarda Sheep Meat that Include the Fatty Acid and Alkenyl Composition and the CLA and <Emphasis Type="Italic">Trans</Emphasis>-18:1 Isomers

The total lipids of the longissimus dorsi muscle were analyzed from commercial adult Sarda sheep in Sardina taken from local abattoirs, and in the subsequent year from three local farms in the Sassari region that provided some information on the amount and type of supplements fed to the pasture-fed sheep. The complete lipid analysis of sheep meat included the fatty acids from O-acyl and N-acyl lipids, including the trans- and conjugated linoleic acid (CLA) isomers and the alk-1-enyl ethers from the plasmalogenic lipids. This analysis required the use of a combination of acid- and base-catalyzed methylation procedures, the former to quantitate the O-acyl, N-acyl and alkenyl ethers, and the latter to determine the content of CLA isomers and their metabolites. A combination of gas chromatographic and silver-ion separation techniques was necessary to quantitate all of the meat lipid constituents, which included a prior separation of the trans-octadecenoic acids (18:1) and a separation of fatty acid methyl esters and the dimethylacetals (DMAs) from the acyl and alk-1-enyl ethers, respectively. The alk-1-enyl moieties of the DMAs were analyzed as their stable cyclic acetals. In general, about half of the meat lipids were triacylglycerols, even though excess fat was trimmed from the meat. The higher fat content in the meat appears to be related to the older age of these animals. The variation in the trans-18:1 and CLA isomer profiles of the Sarda sheep obtained from the abattoirs was much greater than in the profiles from the sheep from the three selected farms. Higher levels of 10t-18:1, 7t9c-18:2, 9t11c-18:2 and 10t12c-18:2 were observed in the commercial sheep meat, which reflected the poorer quality diets of these sheep compared to those from the three farms, which consistently showed higher levels of 11t-18:1, 9c11t-18:2 and 11t13c-18:2. In the second study, sheep were provided with supplements during the spring and summer grazing season, which contributed to higher levels of 11t-18:1 and 9c11t-18:2. The farm that provided a small amount of supplements during the spring had the better lipid profile at both time periods. The polyunsaturated fatty acid (PUFA) content was higher in the meat from Sarda sheep from the three farms than in the meat from those sheep obtained from commercial slaughter operations. The plasmalogenic lipid content ranged from 2 to 3% of total lipids, the alk-1-enyl ethers consisted mainly of saturated and monounsaturated moieties, and the trans-18:1 profile was similar to that of the FA. The n-6 (6–8%) and n-3 PUFA (2–3%) contents, the n-6/n-3 ratio (3:1), as well as the saturated fatty acid (SFA) content (42–45%) and the SFA to PUFA ratio (4:1 to 5:1) of the Sarda sheep from the three farms were comparable to sheep meat lipids found in similar commercial operations in Europe. Inclusion of small amounts of supplements for the grazing Sarda sheep resulted in improved quality of sheep meat lipids.     

An Improved Method for Synthesis of <Emphasis Type="Italic">N</Emphasis>-stearoyl and <Emphasis Type="Italic">N</Emphasis>-palmitoylethanolamine

Certain N-acylethanolamines interact with cannabinoid receptors and have anorexic and neuroprotective effects. Traditional methods for the synthesis of N-acylethanolamines use fatty acid chlorides, fatty acid methyl esters, free fatty acids and triacylglycerols as acyl donors to react with ethanolamine. In the present study, we investigated the feasibility of using fatty acid vinyl esters as the acyl donor to synthesize N-stearoyl and N-palmitoylethanolamine. Theoretically, the use of fatty acid vinyl esters should lead to an irreversible reaction because the volatile acetaldehyde by-product is easily removed. Four reaction conditions, i.e. catalyst concentration, substrate ratio, temperature, and time were evaluated. The reaction performed at mild temperatures and with an excess amount of ethanolamine which acted as both reactant and solvent resulted in the formation of high purity N-stearoyl and N-palmitoylethanolamine. When 20 mmol ethanolamine was reacted with 1 mmol vinyl stearate at 80 °C for 1 h with 1% sodium methoxide as catalyst, N-stearoylethanolamine with 96% purity was obtained after the removal of excess ethanolamine without further purification, while N-palmitoylethanolamine with 98% purity was obtained by reacting with the same substrate ratio at 60 °C for 1.5 h with 3% catalyst. Complete conversion of vinyl stearate and palmitate was achieved.     

RP-HPLC/MS-APCI Analysis of Branched Chain TAG Prepared by Precursor-Directed Biosynthesis with <Emphasis Type="Italic">Rhodococcus</Emphasis><Emphasis Type="Italic">erythropolis</Emphasis>

Reversed phase liquid chromatography–atmospheric pressure chemical ionization mass spectrometry (RP-HPLC/MS-APCI) was used to analyze both synthetic triacylglycerols (TAG) having 1–3 branched fatty acids (FA) in the molecule, and natural TAG prepared by precursor directed biosynthesis from valine, leucine and isoleucine and the corresponding branched short-chain acids in cultivations of Rhodococcus erythropolis. The technique made it possible to identify and quantify TAG differing in a single branched-chain FA. Altogether 11 TAG were synthesized, out of which 8 were synthesized stereospecifically. Branched- and straight-chain-TAG were separated and identified while TAG differing only in iso or anteiso FA could not be separated. The APCI mass spectra of iso-, anteiso- and straight-chain TAG were completely identical. The natural material was found to contain 19 TAG having at least one branched FA. Cultivation on six different substrates showed, apart from the presumed and common incorporation of precursors to iso-even, iso-odd and anteiso FA, also some unusual features such as an increase in the content of odd-FA after the addition of Val (attributed to catabolism of Val to propionate) or the appearance of branched monounsaturated FA. The two-sample paired t test, when applied to the TAG, showed that only the pair Val and isobutyrate differ in incorporation into FA—see, e.g. proportions of M/M/O and brM/brM/O (1.2:1.2 and 1.9:1.2, respectively). Also, incorporation of Val (isobutyrate) yielded only TAG having two branched FA in the molecule, whereas Leu and Ile (isovalerate and 2-methyl-butyrate) gave only TAG with a single branched FA in the molecule.     

Synthesis and Structural Analysis of Structured Triacylglycerols with CLA Isomers in the <Emphasis Type="Italic">sn</Emphasis>-2- Position

The present research deals with the chemical esterification of the sn-2- position of sn-1,3-diacylglycerol (sn-1,3-DAG) with 9cis,11trans (c9,t11) and 10trans,12cis (t10,c12) conjugated linoleic acid (CLA) isomers to obtain structured triacylglycerols (TAG); the sn-1,3-DAG substrates were produced from extra virgin olive oil by means of enzymatic reactions while CLA isomers were obtained using a three-step procedure based on alkaline hydrolysis of sunflower oil, urea purification of linoleic acid (LA) and alkaline isomerization of LA. The results showed good levels of CLA incorporation in structured TAG at the tested temperatures: 37.5% at 4 °C and 39.1% at 14 °C. To evaluate the incorporation of CLA isomers in sn-2- position of sn-1,3-DAG structural analysis of the newly synthesized TAG was carried out using an enzymatic and a chemical method. The results of the structural analysis also showed up the occurrence of acyl migration. The pancreatic lipase method allowed the direct determination of the fatty acid composition of TAG sn-2- position but this enzymatic method showed different results (p < 0.05) in respect to the chemical one; this occurrence could be due to an acylic specificity of the lipase. High incorporation of CLA isomers in sn-2- position of TAG was observed, 77.0% at 4 °C and 81.5% at 14 °C, considering the results of the chemical procedure.     

Lipid Classes,Fatty Acid Distributions and Triacylglycerol Molecular Species of Broad Beans (<Emphasis Type="Italic">Vicia faba</Emphasis>)

Seed oils from four legume cultivars of Vicia faba, grown in Japan, were extracted and classified by thin-layer chromatography (TLC) into eight fractions. The major lipid components were triacylglycerols (TAG: 48.8–50.1%) and phospholipids (PL: 47.5–50.5%), while hydrocarbons (HC), steryl esters (SE), free fatty acids (FFA), diacylglycerols (1,3- and 1,2-DAG) and monoacylglycerols (MAG) were present in minor proportions (1.8–2.4%). All lipid samples had high amounts of total unsaturated FA, representing 79.7–82.8% and 77.6–79.7% for TAG and PL, respectively. Molecular species and FA distributions of TAG, isolated from the total lipids in the broad beans, were analyzed by a combination of argentation-TLC and GC. Fourteen different molecular species were detected. With a few exceptions, the main TAG components were S₂D (6.1–8.9%), SD₂ (7.8–10.5%), SMT (6.3–8.5%), M₂D (4.5–6.2%), MD₂ (18.9–21.8%), D₃ (21.0–23.9%) and MDT (8.1–10.2%) (where S, M, D, and T denote a saturated fatty acid, a monoene, a diene, and a triene, respectively). These results suggest that the lipid classes, FA distributions and TAG molecular species of broad beans are not dependent on the cultivation areas during the growing season.     

Identification of Crepenynic Acid in the Seed Oil of <Emphasis Type="Italic">Atractylodes lancea</Emphasis> and <Emphasis Type="Italic">A. macrocephala</Emphasis>

Atractylodes rhizome is widely used in traditional Chinese herbal medicine. Although the chemical composition of the root has been studied in detail, the oil content and fatty acid composition of the seeds of Atractylodes species have not been reported. Fatty acyl composition of seeds from Atractylodes lancea and A. macrocephala was determined by gas chromatography and mass spectrometry of fatty acid methyl esters and 3-pyridylcarbinol esters. The predominant fatty acid in the seeds of both species was linolenic acid, but the unusual acetylenic fatty acid, crepenynic acid (cis-9-octadecen-12-ynoic acid), was also observed at levels of 18% in A. lancea and 13–15% in A. macrocephala. Fatty acid content was 24% for the samples of A. lancea and 16–17% for samples from A. macrocephala. sn-1,3 regioselective lipase digestion of seed lipids revealed that crepenynic acid was absent from the sn-2 position of the seed triacylglycerol. Crepenynic acid was also found in the seed oil of Jurinea mollis at 24% and was not present in the sn-2 position of the TAG. A contrasting distribution of crepenynic acid was found in the oil of Crepis rubra, suggesting differences in crepenynic acid synthesis or TAG assembly between these species.     

Cyanolipid-rich seed oils from <Emphasis Type="Italic">Allophylus natalensis</Emphasis> and <Emphasis Type="Italic">A. dregeanus</Emphasis>

As a continuation of our study on plants of the Sapindaceae, the chemical composition of the oil extracted from seeds of Allophylus natalensis (Sonder) De Winter and of A. dregeanus (Sonder) De Winter has been investigated. The oil from both species contained approximately equal amounts of TAG and type I cyanolipids (CL), 1-cyano-2-hydroxymethylprop-2-en-1-oldiesters, with minor amounts of type III CL, 1-cyano-2-hydroxymethylprop-1-en-3-ol-diesters. Structural investigation of the oil components was accomplished by chemical, chromatographic (TLC, CC, GC, and GC-MS), and spectroscopic (IR, NMR) means. GC and GC-MS analysis showed that C₂₀ FA were dominant in the CL components of the oil from the two species (44–80% vs. 21–26% in TAG), with cis-11-eicosenoic acid (36–46%) and cis 13-eicosenoic acid (paullinic acid, 23–37%) as the major esterified fatty acyl chains in A. natalensis and A. dregeanus, respectively. cis-Vaccenic acid was particularly abundant (11–31%) in the CL from A. dregeanus, whereas eicosanoic acid (10–22%) was also a major component of CL in both species.     

A new cytotoxic fatty acid (5<Emphasis Type="Italic">Z</Emphasis>,9<Emphasis Type="Italic">Z</Emphasis>)-22-methyl-5,9-tetracosadienoic acid and the sterols from the far Eastern sponge <Emphasis Type="Italic">Geodinella robusta</Emphasis>

A new fatty acid, (5Z,9Z)-22-methyl-5,9-tetracosadienoic acid (1a), and a rare fatty acid, (5Z,9Z)-23-methyl-5,9-tetracosadienoic acid (2a), the predominant constituents of the free fatty acid fraction from the lipids of the sponge Geodinella robusta, were isolated and partly separated by reversed phase high-performance liquid chromatography, followed by multifold crystallization from MeOH to give 1a and 2a in 70% and 60% purity, respectively. These fatty acids were identified as (5Z,9Z)-22-and (5Z,9Z)-23-methyl-5,9-tetracosadienoic acids by nuclear magnetic resonance techniques, including distortionless enhancement by polarization transfer, heteronuclear multiple quantum connectivity, and correlation spectroscopy experiments, as well as from mass-spectrometric data for their methyl esters, the methyl esters of their perhydro derivatives, and their pyrrolidides. Mixtures of 1a and 2a showed cytotoxic activity against mouse Ehrlich carcinoma cells and a hemolytic effect on mouse erythrocytes. The sterol fraction from the same sponge was analyzed by gas liquid chromatography mass spectrometry, and 24-methylenecholesterol was identified as a main constituent of this fraction. The implications of the co-occurrence of membranolytic long-chain fatty acids and 24-methylenecholesterol as a main membrane sterol are discussed in terms of the phenomenon of biochemical coordination.     

<Emphasis Type="Italic">Santalum </Emphasis><Emphasis Type="Italic">insulare</Emphasis> Acetylenic Fatty Acid Seed Oils: Comparison within the <Emphasis Type="Italic">Santalum</Emphasis> Genus

The sandalwood kernels of Santalum insulare (Santalaceae) collected in French Polynesia give seed oils containing significant amounts of ximenynic acid, E-11-octadecen-9-oic acid (64–86%). Fatty acid (FA) identifications were performed by gas chromatography/mass spectrometry (GC/MS) of FA methyl esters. Among the other main eight identified fatty acids, oleic acid was found at a 7–28% level. The content in stearolic acid, octadec-9-ynoic acid, was low (0.7–3.0%). An inverse relationship was demonstrated between ximenynic acid and oleic acid using 20 seed oils. Results obtained have been compared to other previously published data on species belonging to the Santalum genus, using multivariate statistical analysis. The relative FA S. insulare composition, rich in ximenynic acid is in the same order of those given for S. album or S. obtusifolium. The other compared species (S. acuminatum, S. lanceolatum, S. spicatum and S. murrayanum) are richer in oleic acid (40–59%) with some little differences in linolenic content.     

Phospholipid Distribution and Phospholipid Fatty Acids of the Tropical Tunicates <Emphasis Type="Italic">Eudistoma</Emphasis> sp. and <Emphasis Type="Italic">Leptoclinides uniorbis</Emphasis>

Two tunicates, Eudistoma sp. and Leptoclinides uniorbis, collected from the tropical waters off Djibouti were investigated for lipids and phospholipid (PL) fatty acids. PL accounted for 38.2% of the total lipids in Eudistoma sp. and for 30.2% in L. uniorbis. PL classes were quantified by normal-phase high-performance liquid chromatography using an evaporative light-scattering detector and revealed essential differences. Eudistoma sp. contained mainly phosphatidylcholine (PC, 70.3% of total PL) and lysophosphatidylcholine (LPC, 11.9%) and was devoid of phosphatidylserine (PS), whereas the major PL of L. uniorbis was PS (59.1%) followed by PC (22.5%) and LPC (8.8%). Gas chromatography–mass spectrometry analyses of fatty acid (FA) derivatives revealed 38 FA in Eudistoma sp., and 35 FA in L. uniorbis, ranged from C₁₂ to C₂₄ chain lengths. Polyunsaturated FA accounted for 25.9% in Eudistoma sp. and for 32.3% in L. uniorbis. Interestingly, L. uniorbis contained a high percentage (16.7%) of the 20:5n-3 acid (8.9% in Eudistoma sp.) and the 18:4n-3 acid (4.1%). Significant levels of the 20:4n-6 acid were observed in both organisms (7.8 and 6.0% respectively). Eudistoma sp. contained the rare 20:3n-7 acid (2.3%) only recorded to date in hydrothermal vent animals. The cyclopropane dihydrosterculic acid was identified in both tunicates (0.7 and 0.5% respectively). These latter FA, together with some unusual branched saturated and monounsaturated FA, revealed the occurrence of associated bacteria in the tunicates. Another noticeable feature was a series of eight C₁₆ to C₁₈ aldehyde dimethylacetals revealing the presence of plasmalogens at 5.0% in Eudistoma sp. and 14.2% in L. uniorbis. The results of this study were compared with those previously published for other tunicates regarding mainly PL content and FA composition.     

Effect of CLA on the cellular lipids of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

The yeast Saccharomyces cerevisiae was cultivated in the presence of free CLA that was either a pure trans-10, cis-12 isomer, a pure cis-9, trans-11 isomer, or a 1∶1 mixture of the two, and the influence of these supplementations on the content and FA composition of the lipids in the yeast was determined. Neither the pure isomers nor their 1∶1 mixture influenced the growth of the yeast, but the trans-10, cis-12 isomer reduced the amount of cellular lipids by 40%. The reduction in total cellular lipids by the trans-10, cis-12 CLA was due to a reduction in TAG. Both of the isomers were incorporated into the yeast lipids, reaching a proportion of about 33% in TAG. With the incorporation of CLA, the yeast reduced the amount and desaturation of endogenously synthesized FA. These clear and pronounced isomer-specific effects of CLA on the yeast suggest that yeast might be a useful model to obtain a more comprehensive view of the mechanisms of the action of CLA on lipid metabolism.