Polymorphism of linoleic acid (cis-9, cis-12-octadecadienoic acid) and alpha-linolenic acid (cis-9, cis-12, cis-15-octadecatrienoic acid)

Crystallization and polymorphic properties of linoleic acid (cis-9, cis-12-Octadecadienoic acid) (LA) and alpha-linolenic acid (cis-9, cis-12, cis-15-Octadecatrienoic acid) (alpha-LNA) have been studied by optical microscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The DSC analyses presented three polymorphs in LA, and two polymorphs in alpha-LNA. The XRD patterns of the higher- and lower-temperature forms in LA and alpha-LNA showed orthorhombic O'(//)+O-like and O'(//) subcell, which were similar to those of alpha- and gamma-forms of mono-unsaturated fatty acids, respectively. From the solvent crystallization of LA and alpha-LNA in acetonitrile, single crystals of the higher temperature polymorphs have been obtained. The crystal habits of truncated rhombic shape were also similar to those of alpha-forms of the mono-unsaturated fatty acids. The enthalpy and entropy values of fusion and dissolution of the alpha-forms of LA, alpha-LNA and oleic acid showed that the two values decreased with increasing number of the cis-double bond.     

Trans-10, cis-12, but not cis-9, trans-11 CLA isomer,inhibits brown adipocyte thermogenic capacity

Conjugated linoleic acid (CLA) is reported to have health benefits, including reduction of body fat. Previous studies have shown that brown adipose tissue (BAT) is particularly sensitive to CLA-supplemented diet feeding. Most of them use mixtures containing several CLA isomers, mainly cis-9, trans-11 and trans-10, cis-12 in equal concentration. Our aim was to characterize the separate effects of both CLA isomers on thermogenic capacity in cultured brown adipocytes. The CLA isomers showed opposite effects. Hence, on the one hand, trans-10, cis-12 inhibited uncoupling protein (UCP) 1 induction by norepinephrine (NE) and produced a decrease in leptin mRNA levels. These effects were associated with a blockage of CCAAT-enhancer-binding protein-alpha and peroxisome proliferator-activated receptor-gamma(2) mRNA expression. On the other hand, cis-9, trans-11 enhanced the UCP1 elicited by NE, an effect reported earlier for polyunsaturated fatty acids and also observed here for linoleic acid. These findings could explain, at least in part, the effects observed in vivo when feeding a CLA mixture supplemented diet as a result of the combined action of CLA isomers (reduction of adipogenesis and defective BAT thermogenesis that could be through trans-10, cis-12 and enhanced UCP1 thermogenic capacity through cis-9, trans-11).     

Gas chromatography-mass spectrometry determination of metabolites of conjugated cis-9,trans-11,cis-15 18:3 fatty acid

Structural determination of polyunsaturated fatty acids by gas chromatography-mass spectrometry (GC-MS) requires currently the use of nitrogen containing derivatives such as picolinyl esters, 4,4-dimethyloxazoline or pyrrolidides derivatives. The derivatization is required in most cases to obtain low energy fragmentation that allows accurate location of the double bonds. In the present work, the following metabolites of rumelenic (cis-9,trans-11,cis-15 18:3) acid, from rat livers, were identified: cis-8,cis-11,trans-13,cis-17 20:4, cis-5,cis-8,cis-11,trans-13,cis-17 20:5, cis-7,cis-10,cis-13,trans-15,cis-19 22:5, and cis-4,cis-7,cis-10,cis-13,trans-15,cis-19 22:6 acids by GC-MS as their 4,4-dimethyloxazoline and methyl esters derivatives. Specific fragmentation of the methyl ester derivatives revealed some similarity with their corresponding DMOX derivatives. Indeed, intense ion fragments at m/z=M+-69, corresponding to a cleavage at the center of a bis-methylene interrupted double bond system were observed for all identified metabolites. Moreover, intense ion fragments at m/z=M+-136, corresponding to allylic cleavage of the n-12 double bonds were observed for the C20:5, C22:5, C22:6 acid metabolites. For the long chain polyunsaturated fatty acids from the rumelenic metabolism, we showed that single methyl esters derivatives might be used for both usual quantification by GC-FID and identification by GC-MS.     

Formation of cis-3-hexenal,trans-2-hexenal and cis-3-hexenol in macerated Thea sinensis leaves

Thea sinensis; Theaceae; tea; cis-3-hexenal: leaf aldehyde; leaf alcohol; linolenic acid; biosynthesis of leaf alcohol.Linolenic acid and cis-3-hexenal were found in macerated leaves of Thea sinensis and this aldehyde may be produced from linolenic acid by an enzyme contained in macerated leaves in the presence of oxygen. This aldehyde was easily isomerized to trans-2-hexenal, and was converted to cis-3-hexenol by alcohol dehydrogenase. During maceration of freshly picked tea leaves, the amounts of trans-2-hexenal quickly increased and were influenced by maceration time, heating, oxygen and the pH. But in unpicked tea leaves the occurrence of trans-2-hexenal is extremely doubtful.     

Two oligostilbenes,cis- and trans-diptoindonesin B,from Dryobalanops oblongifolia

Two oligostilbenes, cis- and trans-diptoindonesin B, have been isolated from the tree bark of Dryobalanops oblongifolia (Dipterocarpaceae). The structures and relative configurations of both compounds were determined on the basis of spectroscopic evidence, including 2D-NMR spectroscopic analysis.     

Incorporation of cis-9,trans-11 or trans-10,cis-12 conjugated linoleic acid into plasma and cellular lipids in healthy men

This study investigated the incorporation of cis-9,trans-11 conjugated linoleic acid (c9,t11 CLA) and trans-10,cis-12-CLA (t10,c12 CLA) into plasma and peripheral blood mononuclear cell (PBMC) lipids when consumed as supplements highly enriched in these isomers. Healthy men (n = 49, age 31 +/- 8 years) consumed one, two, and four capsules containing approximately 600 mg of either c9,t11 CLA or t10,c12 CLA per capsule for sequential 8 week periods followed by a 6 week washout before consuming the alternative isomer. Both isomers were incorporated in a dose-dependent manner into plasma phosphatidylcholine (PC) (c9,t11 CLA r = 0.779, t10,c12 CLA r = 0.738; P < 0.0001) and cholesteryl ester (CE) (c9,t11 CLA r = 0.706, t10,c12 CLA r = 0.788; P < 0.0001). Only t10,c12 CLA was enriched in plasma nonesterified fatty acids. Both c9,t11 CLA and t10,c12 CLA were incorporated linearly into PBMC total lipids (r = 0.285 and r = 0.273, respectively; P < 0.0005). The highest concentrations of c9,t11 CLA and t10,c12 CLA in PBMC lipids were 3- to 4-fold lower than those in plasma PC and CE. These data suggest that the level of intake is a major determinant of plasma and PBMC CLA content, although PBMCs appear to incorporate both CLA isomers less readily.     

Quantitative gas chromatographic method for the analysis of cis-9, trans-11 and trans-10, cis-12 isomers of the conjugated linoleic acid in liver

A quantitative GC method for conjugated linoleic acid (CLA) isomers of physiological significance (cis-9, trans-11 CLA and trans-10, cis-12 CLA) as non-esterified fatty acids (NEFA) or triacylglycerols (TAG) was developed. Furthermore, the effect of the internal standard addition point (sample or fat extract) was studied. Response linearity, recovery and precision assays, detection and quantification limits were determined. Linearity was demonstrated over a range from 0.1 to 10 microg/mL. When CLA isomers were present as NEFA, the recovery significantly decreased (P< or =0.05) from 76% to 27.1% (cis-9, trans-11 CLA) and 28.5% (trans-10, cis-12 CLA) when the standards were added to the fat extract or to the initial tissue, respectively. As an application, liver samples from hamsters fed a diet supplemented with both CLA isomers were analyzed. The CLA isomers in liver samples were detected with reasonable reproducibility.     

trans-2, cis-4-Heptadienoic Acid,One of Metabolites of Sporobolomyces odorus

Water-soluble phospholipase B was purified to homogeneity from Torulaspora delbrueckii cell washings. The washings were concentrated by ultrafiltration, and then a fraction with phospholipase B activity was precipitated with ammonium sulfate, and purified by sequential column chromatographies on Octyl-Sepharose CL-4B, DEAE-Sephacel, and Sepharose 6B. The molecular weight of the enzyme was estimated to be 170,000~200,000 by SDS-polyacrylamide gel electrophoresis and by gel filtration with a Sephadex G-200 column. The isoelectric point of the enzyme was 4.0. The purified enzyme had two pH optima at pH 2.5 and pH 7.5. The activity at acidic pH was greatly stimulated by the divalent metal ions tested, but the activity at alkaline pH was stimulated mainly by Ca²⁺ and Fe²⁺. The purified enzyme had both lysophospholipase activity and phospholipase B activity in a ratio of 37:1 at acidic pH and 73:1 at alkaline pH. The amino acid composition of the enzyme was characterized by high contents of Asp, Ser, Leu, and Gly.     

Production of trans-10, cis-12 Conjugated Linoleic Acid in Rice

Conjugated linoleic acid (CLA) has anti-carcinogenic and anti-atherosclerosis activity, and modulatory effects on the immune system and lipid metabolism. To produce a transgenic rice plant that can accumulate CLA, a linoleate isomerase gene that can convert linoleic acid to trans-10, cis-12 CLA was introduced and expressed under the control of seed-specific promoters from the oleosin and globulin genes. The fatty acid composition of the transgenic rice grain was analyzed by gas chromatography. Although there was no clear difference in the fatty acid composition between seeds from transformed versus untransformed plants, a peak of trans-10, cis-12 CLA methyl ester, which was not present in seeds from untransformed plants, was found in transformed plants. The trans-10, cis-12 CLA comprised an average of 1.3% (w/w) of the total fatty acids in seeds carrying the oleosin promoter in comparison to 0.01% (w/w) in seeds carrying the globulin promoter. In addition, approximately 70 and 28% of the total amount of the CLA isomer were present in the triacylglycerol and free fatty acid fractions, respectively. These results demonstrate the ability to produce fatty acid components of vegetable oils with novel physiological activities in crops.     

cis-2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase and cis-1, 2-dihydro-1,2-dihydroxynaphathalene dehydrogenase catalyze dehydrogenation of the same range of substrates.

Pseudomonas putida strain G7 cis-1,2-dihydro-1, 2-dihydroxynaphthalene dehydrogenase (NahB) and Comamonas testosteroni strain B-356 cis-2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase (BphB) were found to be catalytically active towards cis-2,3-dihydro-2,3-dihydroxybiphenyl (specificity factors of 501 and 5850 s-1 mM-1 respectively), cis-1,2-dihydro-1, 2-dihydroxynaphthalene (specificity factors of 204 and 193 s-1 mM-1 respectively) and 3,4-dihydro-3,4-dihydroxy-2,2',5, 5'-tetrachlorobiphenyl (specificity factors of 1.6 and 4.9 s-1 mM-1 respectively). A key finding in this work is the capacity of strain B-356 BphB as well as Burkholderia cepacia strain LB400 BphB to catalyze dehydrogenation of 3,4-dihydro-3,4-dihydroxy-2,2',5, 5'-tetrachlorobiphenyl which is the metabolite resulting from the catalytic meta-para hydroxylation of 2,2',5,5'-tetrachlorobiphenyl by LB400 biphenyl dioxygenase.     

The metabolism of cis- and trans-decalin

1. The metabolism of cis- and trans-decalin in the rabbit has been investigated. 2. Both hydrocarbons were oxidized to racemic secondary alcohols and excreted as ether glucuronides in amounts equal to about 60% of the dose administered. The principal glucuronides were isolated as triacetyl methyl esters and as sodium salts. 3. cis-Decalin gave rise mainly to (+/-)-cis-cis-2-decalol, together with a little cis-trans-2-decalol, and trans-decalin mainly to (+/-)-trans-cis-2-decalol and a small amount of trans-trans-2-decalol. 4. These results suggest that biological oxidation of the decalins does not occur via a free-radical mechanism. An attempt is made to explain why racemic alcohols are obtained, rather than the more typical optically active products of enzymic reaction, and a mechanism is proposed. It is suggested that enzymes similar to steroid hydroxylases are involved.     

Different mechanisms of cis-9,trans-11- and trans-10,cis-12- conjugated linoleic acid affecting lipid metabolism in 3T3-L1 cells

Conjugated linoleic acid (CLA) has been shown to reduce body fat mass in various experimental animals. It is valuable to identify its influence on enzymes involved in energy expenditure, apoptosis, fatty acid oxidation and lipolysis. We investigated isomer-specific effects of high dose, long treatment of CLA (75.4 μmol/L, 8 days) on protein and gene expression of these enzymes in cultured 3T3-L1 cells. Proteomics identified significant up- or down-regulation of 52 proteins by either CLA isomer. Protein and gene expression of uncoupling protein (UCP) 1, UCP3, perilipin and peroxisome proliferator-activated receptor (PPAR) α increased whereas UCP2 reduced for both CLA isomers. And eight-day treatment of trans-10,cis-12 CLA, but not cis-9,trans-11 CLA, significantly up-regulated protein and mRNA levels of PKA (P<.05), CPT-1 and TNF-α (P<.01). Compared to protein expression, both isomers did not significantly influence the mRNA expression of HSL, ATGL, ACO and leptin. In conclusion, high-dose, long treatment of cis-9,trans-11 CLA did not promote apoptosis, fatty acid oxidation and lipolysis in adipocytes, but may induce an increase in energy expenditure. trans-10,cis-12 CLA exhibited greater influence on lipid metabolism, stimulated adipocyte energy expenditure, apoptosis and fatty acid oxidation, but its effect on lipolysis was not obvious.     

Synthesis of cis-lactone lignan, cis-(2S,3R)-parabenzlactone, from L-arabinose

As a model synthesis on cis-2,3-dibenzyl-4-butanolide lignan, cis-(2S,3R)-parabenzlactone bearing a chiral benzyl alcohol moiety was stereoselectively synthesized from L-arabinose.     

The rate of reduction of cis-, cis-, trans-[PtIV(NH2Pri)2Cl2(OH)2], CHIP,the anti-cancer drug by ascorbic acid

cis,cis,trans-[Pt^IV(NH₃)₂Cl₂(OH)₂] reacts reversibly with ascorbic acid to give dehydroascorbic acid and mainly cis-[Pt^II(NH₂Prⁱ)₂Cl₂]. The parameters for the forward reaction are: k_f = 0.584 M⁻ s⁻ at 37.0 °C, ΔH^≠_f = 108.6 −+ 6.4 kJ mol⁻¹ andΔS^≠_f = 101 −+ 22 J K⁻¹ mol⁻¹.     

Production of the taste/odor-causing compound,trans-2,cis-6-nonadienal,within the Synurophyceae

Although several species of the Synurophyceae have been associated with taste and odor problems in potable water supplies, electron microscopic-based field studies linked problematic blooms only toSynura petersenii Korshikov. Eventually, the organic compoundtrans-2,cis-6-nonadienal was implicated to cause the associated cucumberlike odors. The objective of this study was to survey unialgal cultures of various Synurophycean species for the occurrence oftrans-2,cis-6-nonadienal. The compound was detected throughout a 24-day growth assay with aS. petersenii isolate, but was not detected in an identical assay withSynura sphagnicola (Korshikov) Korshikov. In separate 24-day cultures,trans-2,cis-6-nonadienal was detected in two isolates from theS. petersenii species complex, but was not detected in isolates of twoMallomonas or fourSynura taxa not from theS. petersenii complex. These results support the hypothesis that production oftrans-2,cis-6-nonadienal is unique to taxa within theS. petersenii complex. When contrast-enhancing optics and specific specimen preparation techniques are employed, light microscopy can be used to distinguish taxa in theS. petersenii complex from all other Synurophycean taxa. These methods are suggested as an efficient way to monitortrans-2,cis-6-nonadienal-producing taxa in potable water supplies.Author for correspondence     

cis-6-oxo-hexahydro-2-oxa-1,4-diazapentalene and cis-6-oxo-hexahydropyrrolo[3,2-c]pyrazole based scaffolds: design rationale, synthesis and cysteinyl proteinase inhibition

The 5,5-bicycles cis-6-oxo-hexahydro-2-oxa-1,4-diazapentalene 3 and cis-6-oxo-hexahydropyrrolo[3,2-c]pyrazole 4 were designed as rotationally restricted templates towards the preparation of inhibitors of CAC1 cysteinyl proteinases. The design strategy was exemplified through the solution and solid phase preparation of potent inhibitors of human cathepsin K and may potentially be applied to inhibitors of other CAC1 proteinases.