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ABSTRACT: Simple and fast method of positional analysis of fatty acid composition of phosphatidylcholine (PC) from egg-yolk and soy has been elaborated. The key step of the procedure was complete ethanolysis of PC catalyzed by sn-1,3 specific lipase from Mucor miehei (Lipozyme). 2-Acyl-lysophosphatidylcholine (2-acyl LPC), fatty acids ethyl esters (FAEEs) and free fatty acids (FAs) were formed in this process. No acyl migration was observed during the reaction. The products were entirely separated from the products mixture by simple extraction in water:hexane (2:3v/v) system. The hexane fraction containing free FAs and FAEEs was treated with BF(3)/Et(2)O in ethanol to obtain only FAEEs. The analysis of FAEEs by GC gave the composition of the FAs in the sn-1 position of the PC. 2-Acyl LPC from water fraction after precipitation in cold (-20°C) acetone was converted into FAEEs and analyzed by gas chromatography (GC) to determine FAs composition in the sn-2 position of the PC.
Food Chemistry 12/2012; 135(4):2542-8. · 3.65 Impact Factor
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ABSTRACT: An assay for quantitative analysis of phosphatidylcholine (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and its hydrolysis products: 1-hydroxy-2-palmitoyl-sn-glycero-3-phosphocholine and 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine, sn-glycero-3-phosphocholine and palmitic acid using high-performance liquid chromatography with charge aerosol detector (CAD) was developed. The separation of the compounds of interest was achieved on a reversed-phase/hydrophilic interaction stationary phase with a mobile phase consisting of acetonitrile:methanol:10mM ammonium acetate solution. The method was applied to control the acyl migration process of LPC regioisomers in the most common solvents used in the synthesis or modification of PC.
Talanta 05/2012; 94:22-9. · 3.79 Impact Factor
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ABSTRACT: The metabolism of δ-iodo-γ-lactones containing cyclohexane ring with an increasing number of methyl substituents in Absidia cylindrospora was studied and seven metabolites were isolated as the products of biotransformations of these substrates. They were formed as the result of various dehalogenation pathways and four of them (hydroxylactones and epoxylactone) turned out to be new compounds. The conversion of substrates ranged from 60% to 90% and the highest conversion was observed for the iodolactone with an unsubstituted cyclohexane ring. The products were fully characterized by the spectroscopic methods and for the hydroxylactone with gem-dimethyl group at C-5 and hydroxylactone with trimethylcyclohexane system the crystal structures were obtained. The main products formed in the process of hydrolytic dehalogenation were δ-hydroxy-γ-lactones with the hydroxy group located cis in relation to lactone moiety. In case of lactone with 4,4,6-trimethylcyclohexane system the dehydrohalogenation followed by the epoxidation of double bond was also observed. One of the metabolites 4,5-epoxy-2,2,6-trimethyl-9-oxabicyclo[4.3.0]nonan-8-one was formed in the sequence of three reactions: hydroxylation at C-5, translactonization and intramolecular nucleophilic substitution of the iodine by the hydroxy group. Some of the isolated products of transformation of the iodolactone with trimethylcyclohexane system were obtained as the single enantiomers. The application of fungi studied to the dehalogenation of iodolactones could be a useful method in the production of new metabolites with oxygen-containing functional groups with antifeedant activity.
Enzyme and microbial technology. 04/2011; 48(4-5):326-33.
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ABSTRACT: The effect of feed supplementation with humic-fat preparations on the fatty acid composition of egg yolk phospholipid fractions was studied. The Lohmann Brown was the experimental hen strain and two feeding mixtures were applied – the standard feed and the mixture supplemented with humic-fat preparations. The fatty acid profile of yolk lipids was significantly affected (P = .05) by the supplementation of feed and total increase of n-3 polyunsaturated fatty acids (PUFA) was established. A different distribution of n-3 PUFA in egg yolk lipid fractions was observed: α-linolenic acid (18:3) was found in the triacylglycerol fraction, whereas docosahexaenoic acid (22:6) was detected in the phospholipid fractions. Supplementation of the hen’s diet with humic-fat preparations resulted in the production of n-3 enriched eggs with decreased n-6/n-3 ratio in all phospholipid fractions in comparison to the eggs from the control group.Research highlights► Supplementation of feeds with humic-fat preparations results in the enrichment of eggs with n-3 PUFA. ► The n-6/n-3 ratio can be decreased to the range of 2.3–3.1. ► α-Linolenic acid is deposited in TAG whereas DHA in pure PL fractions (PC and PE). ► PUFA are incorporated in the sn-2 position of glycerol backbone.
Food Chemistry. 126(3):1013-1018.
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ABSTRACT: Three bicyclic saturated γ-lactones with various numbers of methyl groups at the cyclohexane ring were transformed into the corresponding hydroxylactones. The most effective biohydroxylations were performed by means of cultures Fusarium culmorum and Absidia cylindrospora. Biotransformations of lactones 4a and b afforded the hydroxylactones with the secondary hydroxy groups (5a and b), whereas the hydroxy group introduced into the lactone 4c turned out to be tertiary giving the product 5c.
Journal of Molecular Catalysis B Enzymatic 29:13-18. · 2.73 Impact Factor
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ABSTRACT: The strain Absidia cylindrospora was chosen among eight fungal strains for the biotransformation of unsaturated lactones 1a–c. The processes were carried out by means of shaken cultures. The compounds 1a and 1b were efficiently converted into the corresponding trans-epoxylactones (2a and 2b), whereas the transformation of 1c gave the unsaturated hydroxylactone 3, with the tertiary hydroxy group introduced in the allylic position. The compound 2b was obtained with 100% ee. The structures of compounds 2a and 2b were fully confirmed by the X-ray analysis, which showed the half boat and half chair conformation of cyclohexane ring in these molecules, respectively. All the products were not reported previously in the literature.
Journal of Molecular Catalysis B: Enzymatic.
