- Characterization of Bitter-Tasting Oxylipins in Poppy Seeds (Papaver somniferum L.)
-
Activity-guided fractionation of poppy seed (Papaver somniferum L.) extracts and analysis of fatty acid oxidation model experiments, followed by liquid chromatography time-of-flight mass spectrometry, tandem mass spectrometry, and one-/two-dimensional nuclear magnetic resonance experiments, revealed the chemical structures of five bitter-tasting fatty acids (1-5), three monoglycerides (6-8), six C18-lipidoxidation products (9-14), and four lipid oxidation degradation products (15 and 17-19) as well as two previously unreported monoglyceride oxidation degradation products, namely, 9-(2′,3′-dihydroxypropyloxy)-9-oxononaic acid (1-azeloyl-rac-glycerol, 16) and 1-(2′,3′-dihydroxypropyl)-8-(5″-oxo-2″,5″-dihydrofruan-2″-yl)-octonoate (1-ODFO-rac-glycerol, 20). Sensory studies exhibited low bitter taste threshold concentrations between 0.08 and 0.29 mmol/L, particularly for the higher oxidated C18-fatty acids trihydroxyoctadecenoic acid (THOE, 12), 12,13-dihydroxy-9-oxo-10-octadecenoic acid (12,13-diOH-9-oxo, 13), and 9,10-dihydroxy-13-oxo-11-octadecenoic acid (9,10-diOH-13-oxo, 14) as well as for the lipidoxidation degradation products 4-hydroxy-2-noneic acid (4-HNA, 17), 4-hydroxy-2-docecendienoic acid (HDdiA, 18), and 8-(5′-oxo-2′,5′-dihydrofuran-2′-yl)-octanoic acid (ODFO, 20).
- Lainer, Johanna,Dawid, Corinna,Dunkel, Andreas,Glaser, Peter,Wittl, Stephanie,Hofmann, Thomas
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p. 10361 - 10373
(2020/01/31)
-
- Tandem IBX-Promoted Primary Alcohol Oxidation/Opening of Intermediate β,γ-Diolcarbonate Aldehydes to (E)-γ-Hydroxy-α,β-enals
-
A tandem IBX-promoted oxidation of primary alcohol to aldehyde and opening of intermediate β,γ-diolcarbonate aldehyde to (E)-γ-hydroxy-α,β-enal has been developed. Remarkably, the carbonate opening delivered exclusively (E)-olefin and no over-oxidation of γ-hydroxy was observed. The method developed has been extended to complete the stereoselective total synthesis of both (S)- and (R)-coriolides and d-xylo- and d-arabino-C-20 guggultetrols.
- Kumari, Anupama,Gholap, Sachin P.,Fernandes, Rodney A.
-
p. 2278 - 2290
(2019/06/17)
-
- Oxygenation reactions catalyzed by the F557V mutant of soybean lipoxygenase-1: Evidence for two orientations of substrate binding
-
Plant lipoxygenases oxygenate linoleic acid to produce 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid (13(S)-HPOD) or 9-hydroperoxy-10E,12Z-octadecadienoic acid (9(S)-HPOD). The manner in which these enzymes bind substrates and the mechanisms by which they control regiospecificity are uncertain. Hornung et al. (Proc. Natl. Acad. Sci. USA 96 (1999) 4192–4197) have identified an important residue, corresponding to phe-557 in soybean lipoxygenase-1 (SBLO-1). These authors proposed that large residues in this position favored binding of linoleate with the carboxylate group near the surface of the enzyme (tail-first binding), resulting in formation of 13(S)-HPOD. They also proposed that smaller residues in this position facilitate binding of linoleate in a head-first manner with its carboxylate group interacting with a conserved arginine residue (arg-707 in SBLO-1), which leads to 9(S)-HPOD. In the present work, we have tested these proposals on SBLO-1. The F557V mutant produced 33% 9-HPOD (S:R = 87:13) from linoleic acid at pH 7.5, compared with 8% for the wild-type enzyme and 12% with the F557V,R707L double mutant. Experiments with 11(S)-deuteriolinoleic acid indicated that the 9(S)-HPOD produced by the F557V mutant involves removal of hydrogen from the pro-R position on C-11 of linoleic acid, as expected if 9(S)-HPOD results from binding in an orientation that is inverted relative to that leading to 13(S)-HPOD. The product distributions obtained by oxygenation of 10Z,13Z-nonadecadienoic acid and arachidonic acid by the F557V mutant support the hypothesis that ω6 oxygenation results from tail-first binding and ω10 oxygenation from head-first binding. The results demonstrate that the regiospecificity of SBLO-1 can be altered by a mutation that facilitates an alternative mode of substrate binding and adds to the body of evidence that 13(S)-HPOD arises from tail-first binding.
- Hershelman, Dillon,Kahler, Kirsten M.,Price, Morgan J.,Lu, Iris,Fu,Plumeri, Patricia A.,Karaisz, Fred,Bassett, Natasha F.,Findeis, Peter M.,Clapp, Charles H.
-
-
- N-linoleoylamino acids as chiral probes of substrate binding by soybean lipoxygenase-1
-
Lipoxygenases catalyze the oxygenation of polyunsaturated fatty acids and their derivatives to produce conjugated diene hydroperoxides. Soybean lipoxygenase-1 (SBLO-1) has been the subject of intensive structural and mechanistic study, but the manner in which this enzyme binds substrates is uncertain. Previous studies suggest that the fatty acyl group of the substrate binds in an internal cavity near the catalytic iron with the polar end at the surface of the protein or perhaps external to the protein. To test this model, we have investigated two pairs of enantiomeric N-linoleoylamino acids as substrates for SBLO-1. If the amino acid moiety binds external to the protein, the kinetics and product distribution should show little or no sensitivity to the stereochemical configuration of the amino acid moiety. Consistent with this expectation, N-linoleoyl-L-valine (LLV) and N-linoleoyl-D-valine (LDV) are both good substrates with kcat/Km values that are equal within error and about 40% higher than kcat/Km for linoleic acid. Experiments with N-linoleoyl-L-tryptophan (LLT) and N-linoleoyl-D-tryptophan (LDT) were complicated by the low critical micelle concentrations (CMC = 6–8 μM) of these substances. Below the CMC, LDT is a better substrate by a factor of 2.7. The rates of oxygenation of LDT and LLT continue to rise above the CMC, with modest stereoselectivity in favor of the D enantiomer. With all of the substrates tested, the major product is the 13(S)-hydroperoxide, and the distribution of minor products is not appreciably affected by the configuration of the amino acid moiety. The absence of stereoselectivity with LLV and LDV, the modest magnitude of the stereoselectivity with LLT and LDT, and the ability micellar forms of LLT and LDT to increase the concentration of available substrate are all consistent with the hypothesis that the amino acid moiety binds largely external to SBLO-1 and interacts with it only weakly.
- Clapp, Charles H.,Pachuski, Justin,Bassett, Natasha F.,Bishop, Kathleen A.,Carter, Gillian,Young, Megan,Young, Thomas,Fu, Yuhan
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p. 170 - 177
(2018/03/24)
-
- Allene Oxide Synthase Pathway in Cereal Roots: Detection of Novel Oxylipin Graminoxins
-
Young roots of wheat, barley, and sorghum, as well as methyl jasmonate pretreated rice seedlings, undergo an unprecedented allene oxide synthase pathway targeted to previously unknown oxylipins 1–3. These Favorskii-type products, (4Z)-2-pentyl-4-tridecene-1,13-dioic acid (1), (2′Z)-2-(2′-octenyl)-decane-1,10-dioic acid (2), and (2′Z,5′Z)-2-(2′,5′-octadienyl)-decane-1,10-dioic acid (3), have a carboxy function at the side chain, as revealed by their MS and NMR spectral data. Compounds 1–3 were the major oxylipins detected, along with the related α-ketols. Products 1–3 were biosynthesized from (9Z,11E,13S)-13-hydroperoxy-9,11-octadecadienoic acid, (9S,10E,12Z)-9-hydroperoxy-10,12-octadecadienoic acid (9-HPOD), and (9S,10E,12Z,15Z)-9-hydroperoxy-10,12,15-octadecatrienoic acid, respectively, via the corresponding allene oxides and cyclopropanones. The data indicate that conversion of the allene oxide into the cyclopropanone is controlled by soluble cyclase. The short-lived cyclopropanones are hydrolyzed to products 1–3. The collective name “graminoxins” has been ascribed to oxylipins 1–3.
- Grechkin, Alexander N.,Ogorodnikova, Anna V.,Egorova, Alevtina M.,Mukhitova, Fakhima K.,Ilyina, Tatiana M.,Khairutdinov, Bulat I.
-
p. 336 - 343
(2018/06/04)
-
- ω-alkynyl lipid surrogates for polyunsaturated fatty acids: Free radical and enzymatic oxidations
-
Lipid and lipid metabolite profiling are important parameters in understanding the pathogenesis of many diseases. Alkynylated polyunsaturated fatty acids are potentially useful probes for tracking the fate of fatty acid metabolites. The nonenzymatic and enzymatic oxidations of ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were compared to that of linoleic and arachidonic acid. There was no detectable difference in the primary products of nonenzymatic oxidation, which comprised cis,trans-hydroxy fatty acids. Similar hydroxy fatty acid products were formed when ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were reacted with lipoxygenase enzymes that introduce oxygen at different positions in the carbon chains. The rates of oxidation of ω-alkynylated fatty acids were reduced compared to those of the natural fatty acids. Cyclooxygenase-1 and -2 did not oxidize alkynyl linoleic but efficiently oxidized alkynyl arachidonic acid. The products were identified as alkynyl 11-hydroxy-eicosatetraenoic acid, alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid, and alkynyl prostaglandins. This deviation from the metabolic profile of arachidonic acid may limit the utility of alkynyl arachidonic acid in the tracking of cyclooxygenase-based lipid oxidation. The formation of alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid compared to alkynyl prostaglandins suggests that the ω-alkyne group causes a conformational change in the fatty acid bound to the enzyme, which reduces the efficiency of cyclization of dioxalanyl intermediates to endoperoxide intermediates. Overall, ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid appear to be metabolically competent surrogates for tracking the fate of polyunsaturated fatty acids when looking at models involving autoxidation and oxidation by lipoxygenases.
- Beavers, William N.,Serwa, Remigiusz,Shimozu, Yuki,Tallman, Keri A.,Vaught, Melissa,Dalvie, Esha D.,Marnett, Lawrence J.,Porter, Ned A.
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p. 11529 - 11539
(2014/10/15)
-
- Stereospecific production of 9R-hydroxy-10E,12Z-octadecadienoic acid from linoleic acid by recombinant Escherichia coli cells expressing 9R-lipoxygenase from Nostoc sp. SAG 25.82
-
One of the most significant properties of lipoxygenase (LOX) as a biocatalyst is its stereo-selective oxygenation. In this study, the stereo-specific production of 9R-hydroxy-10E,12Z-octadecadienoic acid (9R-HODE) from linoleic acid was achieved using whole recombinant Escherichia coli cells expressing LOX from Nostoc sp. SAG 25.82. The optimal conditions for the production of 9R-HODE were pH 7.5, 25 °C, 40 g l-1 cells, 15 g l-1 linoleic acid, 2% (v/v) methanol, 1 working volume/oxygen volume/min (vvm) oxygenation rate, and 250 rpm agitation speed in 500 ml-baffled flask containing a working volume of 50 ml. Under these optimized conditions, whole recombinant cells expressing 9R-LOX protein produced 14.3 g l-1 9R-HODE for 1 h, with a conversion yield of 95% (w/w) and a productivity of 14.3 g l-1 h-1. The oxygen supply method significantly influenced stereo- and regio-selectivity of the oxygenation of linoleic acid. Among the oxygen supply methods tested, oxygenation (1 vvm) with agitation (250 rpm) resulted in the highest 9R/13S-HODE ratio of the products at 96:4. This is the first application using whole recombinant cells harboring R-specific LOX for the stereo-selective production of an R-specific hydroxy fatty acid.
- Kim, Kyoung-Rok,Seo, Min-Ho,Park, Jin-Byung,Oh, Deok-Kun
-
-
- Quantitation of hydroperoxy-, keto- and hydroxy-dienes during oxidation of FAMEs from high-linoleic and high-oleic sunflower oils
-
The objective of this work was to study the quantitative formation of hydroperoxydienes, ketodienes and hydroxydienes during autoxidation at 40 °C of fatty acid methyl esters derived from two sunflower oils with different degree of unsaturation, high-linoleic sunflower oil and high-oleic sunflower oil. The analysis of the oxidation compounds was carried out by NP-HPLC-UV and results were compared to the specific extinction at 232 nm (K 232) and the peroxide value (PV). Analysis of FAME polymers by HPSEC was also performed to discard samples of advanced oxidation. Results showed that the contents of hydroperoxydienes with respect to the PV were higher for the high linoleic (HL) sample. At the end of the period of slow polymerization (ΔPol ≤ 1 wt%), the content of hydroperoxydienes was found to be 86.0 and 30.7 μg/mg for the HL and high oleic (HO) samples, respectively. Throughout this period, hydroperoxydienes constituted around 90 and 50 wt% of the total hydroperoxides in the HL and HO samples, respectively, suggesting that a significant oxidation of oleic acid also occurred in both samples. The contents of ketodienes and hydroxydienes as a whole constituted 2-3 wt% of the diene compounds analyzed at the end of the period of slow polymerization. Higher contents of ketodienes than of hydroxydienes were found throughout the oxidation time, and the ratio between the contents of ketodienes and hydroxydienes increased with a factor that changed from 1 to 2 throughout the period of slow polymerization.
- Morales, Arturo,Dobarganes, Carmen,Marquez-Ruiz, Gloria,Velasco, Joaquin
-
experimental part
p. 1271 - 1279
(2011/08/21)
-
- Physcomitrella patens has lipoxygenases for both eicosanoid and octadecanoid pathways
-
Mosses have substantial amounts of long chain C20 polyunsaturated fatty acids, such as arachidonic and eicosapentaenoic acid, in addition to the shorter chain C18 α-linolenic and linoleic acids, which are typical substrates of lipoxygenases in flowering p
- Anterola, Aldwin,G?bel, Cornelia,Hornung, Ellen,Sellhorn, George,Feussner, Ivo,Grimes, Howard
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experimental part
p. 40 - 52
(2009/07/11)
-
- Synthesis and biological activity of hydroxylated derivatives of linoleic acid and conjugated linoleic acids
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Allylic hydroxylated derivatives of the C18 unsaturated fatty acids were prepared from linoleic acid (LA) and conjugated linoleic acids (CLAs). The reaction of LA methyl ester with selenium dioxide (SeO2) gave mono-hydroxylated derivatives, 13-hydroxy-9Z,11E-octadecadienoic acid, 13-hydroxy-9E,11E-octadecadienoic acid, 9-hydroxy-10E,12Z-octadecadienoic acid and 9-hydroxy-10E,12E-octadecadienoic acid methyl esters. In contrast, the reaction of CLA methyl ester with SeO2 gave di-hydroxylated derivatives as novel products including, erythro-12,13-dihydroxy-10E-octadecenoic acid, erythro-11,12-dihydroxy-9E-octadecenoic acid, erythro-10,11-dihydroxy-12E-octadecenoic acid and erythro-9,10-dihydroxy-11E-octadecenoic acid methyl esters. These products were purified by normal-phase short column vacuum chromatography followed by high-performance liquid chromatography (HPLC). Their chemical structures were characterized by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR). The allylic hydroxylated derivatives of LA and CLA exhibited moderate in vitro cytotoxicity against a panel of human cancer cell lines including chronic myelogenous leukemia K562, myeloma RPMI8226, hepatocellular carcinoma HepG2 and breast adenocarcinoma MCF-7 cells (IC50 10-75 μM). The allylic hydroxylated derivatives of LA and CLA also showed toxicity to brine shrimp with LD50 values in the range of 2.30-13.8 μM. However these compounds showed insignificant toxicity to honeybee at doses up to 100 μg/bee.
- Li, Zhen,Tran, Van H.,Duke, Rujee K.,Ng, Michelle C.H.,Yang, Depo,Duke, Colin C.
-
experimental part
p. 39 - 45
(2010/03/31)
-
- Identification of an amino acid determinant of pH regiospecificity in a seed lipoxygenase from Momordica charantia
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Lipoxygenases (LOX) form a heterogeneous family of lipid peroxidizing enzymes, which catalyze specific dioxygenation of polyunsaturated fatty acids. According to their positional specificity of linoleic acid oxygenation plant LOX have been classified into linoleate 9- and linoleate 13-LOX and recent reports identified a critical valine at the active site of 9-LOX. In contrast, more bulky phenylalanine or histidine residues were found at this position in 13-LOX. We have recently cloned a LOX-isoform from Momordica charantia and multiple amino acid alignments indicated the existence of a glutamine (Gln599) at the position were 13-LOX usually carry histidine or phenylalanine residues. Analyzing the pH-dependence of the positional specificity of linoleic acid oxygenation we observed that at pH-values higher than 7.5 this enzyme constitutes a linoleate 13-LOX whereas at lower pH, 9-H(P)ODE was the major reaction product. Site-directed mutagenesis of glutamine 599 to histidine (Gln599His) converted the enzyme to a pure 13-LOX. These data confirm previous observation suggesting that reaction specificity of certain LOX-isoforms is not an absolute enzyme property but may be impacted by reaction conditions such as pH of the reaction mixture. We extended this concept by identifying glutamine 599 as sequence determinant for such pH-dependence of the reaction specificity. Although the biological relevance for this alteration switch remains to be investigated it is of particular interest that it occurs at near physiological conditions in the pH-range between 7 and 8.
- Hornung, Ellen,Kunze, Susan,Liavonchanka, Alena,Zimmermann, Grit,Kuehn, Diana,Fritsche, Kathrin,Renz, Andreas,Kuehn, Hartmut,Feussner, Ivo
-
scheme or table
p. 2774 - 2780
(2009/04/10)
-
- Properties of a mini 9R-lipoxygenase from Nostoc sp. PCC 7120 and its mutant forms
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Lipoxygenases (LOXs) consist of a class of enzymes that catalyze the regio- and stereospecific dioxygenation of polyunsaturated fatty acids. Current reports propose that a conserved glycine residue in the active site of R-lipoxygenases and an alanine residue at the corresponding position in S-lipoxygenases play a crucial role in determining the stereochemistry of the product. Recently, a bifunctional lipoxygenase with a linoleate diol synthase activity from Nostoc sp. PCC7120 with R stereospecificity and the so far unique feature of carrying an alanine instead of the conserved glycine in the position of the sequence determinant for chiral specificity was identified. The recombinant carboxy-terminal domain was purified after expression in Escherichia coli. The ability of the enzyme to use linoleic acid esterified to a bulky phosphatidylcholine molecule as a substrate suggested a tail-fist binding orientation of the substrate. Site directed mutagenesis of the alanine to glycine did not cause alterations in the stereospecificity of the products, while mutation of the alanine to valine or isoleucine modified both regio- and enantioselectivity of the enzyme. Kinetic measurements revealed that substitution of Ala by Gly or Val did not significantly influence the reaction characteristics, while the A162I mutant showed a reduced vmax. Based on the mutagenesis data obtained, we suggest that the existing model for stereocontrol of the lipoxygenase reaction may be expanded to include enzymes that seem to have in general a smaller amino acid in R and a bulkier one in S lipoxygenases at the position that controls stereospecificity.
- Andreou, Alexandra-Zoi,Vanko, Marian,Bezakova, Lydia,Feussner, Ivo
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p. 1832 - 1837
(2008/09/20)
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- Regio- and stereoselective oxidation of linoleic acid bound to serum albumin: Identification by ESI-mass spectrometry and NMR of the oxidation products
-
An efficient RP-HPLC method was developed for the detection of the oxidation products derived from the AAPH-initiated peroxidation of linoleic acid bound to human serum albumin. Diode array UV-detection allowed the quantification at 234 nm of four regioisomeric hydroperoxyoctadecadienoic acids (HPODE) and four hydroxyoctadecadienoic acids (HODE) while at 280 nm four oxooctadecadienoic acid isomers (KODE) were detected. Full identification of the different underivatized HODE, HPODE and KODE isomers was achieved by negative ESI-mass spectrometry outlining common fragmentation pathways for 9- and 13-regioisomers. Chemical synthesis of 9-(E,Z)-, 9-(E,E)-, 13-(Z,E)- and 13-(E,E)-KODE helped to their structural characterization by 1H NMR. Lipid peroxidation in the presence of albumin proved to be regioselective with a larger accumulation of 13-HPODE and 9-KODE isomers. Thermodynamically more stable E,E-stereoisomers were also favored by albumin for both HPODE and KODE.
- Dufour, Claire,Loonis, Michele
-
-
- Characterization and quantification of free and esterified 9- and 13-hydroxyoctadecadienoic acids (HODE) in barley, germinating barley, and finished malt
-
The analysis of (R)-9- and (S)-9-hydroxy-10E,12Z-octadecadienoic acid as well as (R)-13- and (S)-13-hydroxy-9Z,11E-octadecadienoic acid (HODE) as free acids, esterified in triacylglycerols (storage lipids), and esterified in polar lipids (phospholipids, glycolipids, etc.) in barley, germinating barley, and finished malt was performed using [13-18O1]-(S)-13-HODE isotope dilution assays with GC-MS and straight- and chiral-phase HPLC. 9- and 13-HODE occur approximately racemically in barley, indicating an autoxidation. The enantiomeric excesses increase to 78% S for free 9-HODE and to 58% S for free 13-HODE in germinating barley as a result of lipoxygenase-2 (LOX-2) catalysis, but free HODEs are at low concentration. More than 90% of HODEs in barley and malt are esterified. In the storage lipids of green malt 53 mg/kg 9-HODE and 147 mg/kg 13-HODE were detected. This ratio of 30:70 reflects the regioselectivity of the LOX-2 enzyme in malt. In the polar lipids 45 mg/kg 9-HODE and 44 mg/kg 13-HODE were characterized. The latter indicate a hitherto unknown 9-lipoxygenase activity with polar lipids as substrates. During kilning the contents of most HODEs decreased significantly due to chemical and enzymatic degradation, whereas polar-esterified (R)-13-HODE increased (43%) in the finished malt.
- Hobke, Holger,Garbe, Leif-Alexander,Tressl, Roland
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p. 1556 - 1562
(2007/10/03)
-
- 9-Oxooctadeca-10,12-dienoic acids as Acetyl-CoA carboxylase inhibitors from red pepper (Capsicum annuum L.)
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A methanol extract of red pepper showed potent acetylCoA carboxylase inhibitory activity. The active principles were isolated and identified as (E, E)- and (E, Z)-9-oxooctadeca-10,12-dienoic acids by instrumental analyses. The IC50 values of the compounds were 1.4 x 10-6 and 1.5 x 10-6 M, respectively, their activity being nearly sixty-times higher than that of the common fatty acids themselves. A comparative study of the structure-activity relationship among their related compounds showed that the inhibitory activity was influenced neither by the position and species of the oxygen functional group in the middle of the alkyl chain nor by the configurations of the double bonds. However, it was found that the presence of double bonds between the terminal carboxyl and the mid-chain oxygen functional group lowered the inhibitory activity which could be recovered by hydrogenation of the double bonds.
- Watanebe, Jun,Kawabata, Jun,Kasai, Takanori
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p. 489 - 493
(2007/10/03)
-
- Preparation of fatty acid cholesterol ester hydroperoxides by photosensitized oxidation
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Preparation of fatty acid cholesterol ester hydroperoxides was undertaken with the purpose of evaluating their biological effects on cell growth. Cholesterol stearate, oleate, linoleate and α-linolenate were oxidized using methylene blue as a photosensitizer. The structures of all compounds were established by mass spectrometry and by nuclear magnetic resonance. The photosensitized oxidation of cholesterol oleate gave two hydroperoxide isomers: 9-hydroperoxy-trans-10-octadecenoate, and 10-hydroperoxy-trans-8-octadecenoate. In the case of the cholesterol linoleate, hydroperoxide isomers formed were: 9-hydroperoxy-trans-10, cis-12-octadecadienoate; 10-hydroperoxy-trans-8, cis-12-octadecadienoate; 12-hydroperoxy-cis-9, trans-13-octadecadienoate; 13-hydroperoxy-cis-9, trans-11-octadecadienoate. The oxidation of the cholesterol α-linolenate gave a mixture of six hydroperoxide isomers, at positions 9, 10, 12, 13, 15 and 16 of the fatty acid chain. The photosensitized oxidation of cholesterol stearate produced a formation of hydroperoxide at position 5α of cholesterol. The same hydroperoxide isomers on the fatty acid chain were obtained as described in the literature for the fatty acid methyl esters. Copyright (C) 1999 Elsevier Science Ireland Ltd.
- El Hafidi,Michel,Bascoul,Crastes De Paulet
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p. 127 - 138
(2007/10/03)
-
- Preparative Separation and 1H NMR Identification of Products of Linoleic Acid Autooxidation
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Bulk phase oxidation of linoleic acid in a diffuse system in the dark at 2-5 deg C was found to produce three types of oxygenated derivatives.An effective method of HPLC on the nitrile phase was developed for the analysis and preparative isolation of products, which made it possible to prepare individual structural isomers of each type.After preliminary identification by chemical, chromatographic, and UV methods, the isolated compounds were identified as 9- and 13-isomers of hydroperoxy-, hydroxy-, and ketooctadecadienoic acids with Z-E-conjugated double bond systems.The formation of minor E-E-regioisomers of linoleic acid hydroperoxides was also observed.The assignment of signals in the 1H NMR spectra of the compounds isolated, including homonuclear proton-decoupled spectra, validated the proposed structures.It is suggested that the preferable formation of Z-E-isomers of oxygenated products during linoleic acid autooxidation under low temperature is connected with impossibility of overcoming the energy barrier of primary peroxyradical isomerization.Key words: polyunsaturated fatty acids, peroxidation, isolation and identification of products, high-performance liquid chromatography (HPLC), 1H NMR spectroscopy
- Chudinova, V. V.,Chudinov, M. V.,Eremin, S. V.,Alekseev, S. M.
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p. 470 - 477
(2007/10/03)
-
- High-Performance Liquid Chromatographic Analysis of the Products of Linoleic Acid Oxidation Catalyzed by Pea (Pisum sativum) Seed Lipoxygenases
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An HPLC method is discussed for the analysis of the products formed by the pea (Pisum sativum) lipoxygenase catalyzed oxidation of linoleic acid.The results demonstrate the feasibility of analyzing all of the hydroperoxides, hydroxides, and keto fatty acids in a single chromatographic step and show that it will be possible to analyze the product profile from the lipoxygenase activity contained in a portion of a seed, which will permit the remainder of the seed to be grown on for subsequent generations.The chemical structures of the products have been identified by HPLC analysis and GC-MS. Keywords: Lipoxygenase; hydroperoxides; chromatography
- Wu, Zecai,Robinson, David S.,Domoney, Claire,Casey, Rod
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p. 337 - 342
(2007/10/02)
-
- Aromatase inhibitors from Urtica dioica roots
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Methanolic extracts of stinging nettle (Urtica dioica L.) roots were investigated for aromatase inhibition. Enzyme inhibition was detected only after appropriate chromatographic separation. Inhibitory effects on aromatase could be demonstrated in vitro for a variety of compounds belonging to different classes. The following compounds developed weak to moderate activity: secoisolariciresinol (1), oleanolic and ursolic acid (2 and 3), (9Z,11E)-13-hydroxy-9,11-octadecadienoic acid (4), and 14-octacosanol (5). Inhibitory effects on aromatase have been known to date neither for pentacyclic triterpenes nor for secondary fatty alcohols. The potential physiological significance of the above findings is discussed. Compound 5 is a previously unknown constituent of plants.
- Gansser,Spiteller
-
p. 138 - 140
(2007/10/02)
-
- Auto-growth inhibitory substance from the fresh-water cyanobacterium Phormidium tenue
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An extract of the cyanobacterium P. tenue showed a significant inhibitory effect on its own growth. Bioassay-directed fractionation has led to the identification of the auto-growth inhibitory substance as a mixture of fatty acids. Unsaturated fatty acids such as linoleic and linolenic acids appear to be predominantly responsible for the auto-growth inhibitory effect.
- Yamada,Murakami,Morimoto,Sakakibara
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p. 1863 - 1865
(2007/10/02)
-
- Hydroxyoctadecadienic acid for the treatment of estrogen-dependent disease
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This invention describes the use of a hydroxyoctadecadienic acid, its acid oxidized to keto form or the ester derivatives of the acids, where the ester derivatives are low esters with 1 to 4 carbon atoms for the preparation of a pharmaceutical for treatment of breast carcinomas or benign prostatic hyperplasia. In particular, those compounds are suitable in which the double bonds and the hydroxy group or the oxo group are present on the carbon atoms at positions 9 to 13.
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-
-
- Convergent Stereocontrolled Synthesis of 13-Hydroxy-9Z,11E-octadecadienoic Acid (13-HODE)
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The readily available alkenes (4) and (5) were coupled using a palladium(II) catalyst to give the diene ester (6), a late-stage intermediate to 13-HODE.
- Chan, Cecil,Cox, Philip B.,Roberts, Stanley M.
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p. 971 - 972
(2007/10/02)
-
- Short and Efficient Syntheses of Coriolic Acid
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Coriolic acid (1), a divalent cation ionophore and a self-defensive substance against blast disease in rice plant, has been synthesized by two convenient approaches.
- Rao, A. V. Rama,Reddy, S. Pulla,Reddy, E. Rajarathnam
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p. 4158 - 4159
(2007/10/02)
-
- A STEREOSELECTIVE SYNTHESIS OF CORIOLIC ACID AND DIMORPHECOLIC ACID
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Described herein is a convenient synthesis of coriolic acid (1) and dimorphecolic acid (2), the two natural ionophores derived respectively from bovine heart mitochondria and also shown to be self defensive substances in rice plant against rice blast disease.
- Rao, A. V. Rama,Reddy, E. Rajarathnam,Sharma, G. V. M.,Yadagiri, P.,Yadav, J. S.
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p. 465 - 468
(2007/10/02)
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- APPLICATION OF FURAN OXIDATIONS IN SYNTHESIS: TOTAL SYNTHESIS OF (+/-)-COROLIC ACID
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As a general synthesis approach to compounds containing the cis-trans allylhydroxy functionality ( subunit A), an appropriately substituted furan nucleus is oxidatively cleaved to provide an unsaturated 1,4-dicarbonyl moiety suitably disposed for further elaboration.The total synthesis of (+/-)-coriolic acid demonstrates the utility of the approach.
- Gunn, Bruce P.
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p. 3061 - 3067
(2007/10/02)
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- UNSATURATED HYDROXY FATTY ACIDS, THE SELF DEFENSIVE SUBSTANCES IN RICE PLANT AGAINST RICE BLAST DISEASE
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In addition to the previously described epoxy fatty acids, five hydroxy fatty acids were characterized as self defensive substances produced in the rice plant against rice blast disease.
- Kato, Tadahiro,Yamaguchi, Yoshihiro,Hirano, Takumi,Yokoyama, Toshiro,Uyehara, Tadao,et al.
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p. 409 - 412
(2007/10/02)
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- SOLUBILIZATION AND PROPERTIES OF THE ENZYME-CLEAVING 13-L-HYDROPEROXYLINOLENIC ACID IN TEA LEAVES
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The membrane bound hydroperoxide lyase (E2'') which catalyses the cleavage of 13-L-hydroperoxides (18:3-OOH and 18:2-OOH) of linolenic and linoleic acids to C6-volatile aldehydes (hexenals and n-hexanal) was found to be localized in the chloroplast lamellae of tea leaves.It was selectively solubilized from the lamellae with 0.5percent (w/v) Tween 20.The enzymatic cleavage of the hydroperoxides occurred even under anaerobic conditions.The optimal pH of E2'' was 7-8.The common structural features shown by substrates of E2'' were the presence of a L-hydroperoxy group at ω-6 with a conjugated trans, cis-diene at ω-7 and ω-9 in a C18-fatty acid.E2'' had an apparent Km of 2.5 and 1.9 mM for 18:3-OOH and 18:2-OOH, respectively.No significant differences were found between chloroplast E2'' and solubilized E2''. - Key Word Index - Thea sinensis; Theaceae; tea; hydroperoxide lyase; hexenals; 13-L-hydroperoxylinolenic acid.
- Hatanaka, A.,Kajiwara, T.,Sekiya, J.,Inouye, S.
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- Autoxidation of Model Membrane Systems: Cooxidation of Polyunsaturated Lecithins with Steroids, Fatty Acids, and α-Tocopherol
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The autoxidation of diL-PC and 1S,2A-PC in aqueous emulsion with several cosubstrates was investigated.Cholesterol, 7-dehydrocholesterol, linolic acid, and α-tocopherol were cosubstrates in the autoxidation of dilinoleoylphosphatidylcholine (diLP-PC).The distribution of the products, tc and tt diene hydroperoxides, was determined and evaluated.It was concluded that cholesterol has a lower H atom donating ability (Kp) and 7-dehydrocholesterol a much higher Kp than diL-PC.Linoleic acid when mixed with diL-PC, diP-PC, or a mixture of the two was found to behave analogous to a mixture of just the two lecithins.The cooxidation of diL-PC with a α-tocopherol in the bilayer gave only trans,cis (tc) hydroperoxides, which can be ascribed to a very high kinh for a α-tocopherol, a very efficient antioxidant. 1-Stearoyl-2-arachidonoylphosphatidilcholine (1S,2A-PC)bilayer autoxidation gave a product distribution very similar to arachidonic acid neat autoxidation.However the products from cooxidation of 1S,2A-PC bilayer with α-tocopherol unexpectedly did not include the 5-hydroperoxy eicosatetraenoic acid isomer (5-HPETE), although the 12, 15, 11, 9, and 8 isomers were present in almost equal amounts.
- Weenen, Hugo,Porter, Ned A.
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p. 5216 - 5221
(2007/10/02)
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- Autoxidation of Polyunsaturated Lipids. Factors Controlling the Stereochemistry of Product Hydroperoxides
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The mechanism of the autoxidation of linoleic acid and phospholipid esters of this acid was investigated.The products of autoxidation,13-hydroperoxy-9-cis,11-trans-octadecadienoic (4), 13-hydroperoxy-9-trans,11-trans-octadecadienoic (5), 9-hydroperoxy-10-
- Porter, Ned A.,Weber, Bruce A.,Weenen, Hugo,Khan, Jamil A.
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p. 5597 - 5601
(2007/10/02)
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