Extraction of phospholipid

T Horne, S Holt-Larkin. Solid-phase extraction of phospholipids from hemoglobin solutions using Empore styrene-divinylbenzene disks. J Chromatogr B 695 259-267, 1997. 

Montanari L, Fantozzi P, Snyder JM, King JW. Selective extraction of phospholipids from soybeans with supercritical carbon dioxide and ethanol. J Super-crit Fluids 1999 14 87-93. 

When cell extracts were prepared using a French press, centrifuged at 30 000 xg, and the supernatant further centrifuged at 150 000 xg for 3 h, most of the activity remained in the soluble fraction, establishing that the enzyme separated from the membrane. A 24-fold purified preparation of the enzyme was obtained. The MW of the enzyme was reported to be M,. 340 000. " For optimal activity, the enzyme required Mn, washed membranes or an extract of phospholipids, and an unidentified heat stable factor of MW <10 000. The reaction was strongly stimulated by dithiothreitol and methanol. Since the substrate of the enzyme 3-octaprenyl-4-hydroxybenzoate (49) is membrane bound and the enzyme is stimulated by phospholipid, it has been suggested that the enzyme normally functions in association with the cytoplasmic membrane m A reaction... 

Where the fat in a meat or meat product sample is to be characterized in terms of the fatty acid profile, extraction of the fat with chloroform/methanol is required. This solvent mixture, while it may not give complete fat extraction, is used to ensure no chemical change to the lipids and the extraction of phospholipids. Fatty acid analysis of the extracted fat is undertaken by formation of volatile methyl esters of the fatty acids (ISO 5509 2000) and determination by gas chromatography (ISO 5508 1990). 

Dunford, N.T. and Temelli, F. (1995) Extraction of phospholipids from canola with supercritical carbon... 

Montanari, L., Fantozzi, P., Snyder, J.M., and King, J.W. (1997) Selective extraction of phospholipids from soybeans with supercritical carbon dioxide, in E. Reverchon (ed.), Proceedings of the 4th Italian Conference on Supercritical Fluids and Their Applications, Capri, Italy, pp.81-88. 

Oleic, linoleic and linolenic acids were the major fatty acids in the extracted canola oil. There was a decrease in relative concentrations of oleic (C18 l (0-9) and linolenic acid when ethanol was added as a cosolvent while oleic (C18 l co-7) and linolenic acid concentrations increased significantly p < 0.01). Use of ethanol resulted in extraction of C16 l which is not present when SC-CO2 is used alone. Longer chain fatty acids (C20 0, C22 0 and C22 l) were not present in the SC-CO2 extracts when canola flakes were used as the starting feed material. However, these longer chain fatty acids were present in the extracted oil when ethanol was included as a cosolvent and press cake was the feed material. The extraction of phospholipids using ethanol as a cosolvent, without need for degumming, provides opportunity for the cosmetics and food industry that has yet to be fully exploited. 

Although extraction of lipids from membranes can be induced in atomic force apparatus (Leckband et al., 1994) and biomembrane force probe (Evans et al., 1991) experiments, spontaneous dissociation of a lipid from a membrane occurs very rarely because it involves an energy barrier of about 20 kcal/mol (Cevc and Marsh, 1987). However, lipids are known to be extracted from membranes by various enzymes. One such enzyme is phospholipase A2 (PLA2), which complexes with membrane surfaces, destabilizes a phospholipid, extracts it from the membrane, and catalyzes the hydrolysis reaction of the srir2-acyl chain of the lipid, producing lysophospholipids and fatty acids (Slotboom et al., 1982 Dennis, 1983 Jain et al., 1995). SMD simulations were employed to investigate the extraction of a lipid molecule from a DLPE monolayer by human synovial PLA2 (see Eig. 6b), and to compare this process to the extraction of a lipid from a lipid monolayer into the aqueous phase (Stepaniants et al., 1997). 

Stepaniants et al., 1997] Stepaniants, S., Izrailev, S., and Schulten, K. Extraction of lipids from phospholipid membranes by steered molecular dynamics. J. Mol. Model. 3 (1997) 473-475... 

Figure 38, Patterns obtained from the extract of 10 fd of serum for lipid fraction by thin-layer chromatography. In sequence, starting from the bottom, phospholipids, pee cholesterol, cholesterol aniline as an internal standard, triglycerides, and cholesterol esters. The free fatty acids occur between cholesterol and the internal standard and are only barely visible in the print, on the extreme right. They are readily visible, normally, to the eye.

Lipids can be extracted from biological samples using a variety of organic solvents. A chloroform-methanol solvent is suitable for all lipids but it is possible to extract different classes of lipid selectively on the basis of their solubility in different organic solvents. This may be achieved by the addition of a solvent that will effect either the precipitation or the extraction of the lipids of interest. An example of the former is the precipitation of high concentrations of phospholipids with cold, dry acetone, and of the latter, the extraction of fatty acids into ether or heptane at an acid pH. However, like all solvent extraction procedures these are not entirely specific. 

Formaldehyde prevents the extraction of glycogen but does not preserve soluble polysaccharides. Acid mucopolysaccharides are also not preserved unless they are bound to proteins (3). Formaldehyde is a good fixative for lipids, particularly if 1-2 mM Ca " or Mg + are included in the fixative vehicle (4,5,11). Membrane fixation is improved by reducing lipid extraction (4). It is also thought that fixation with formaldehyde lowers the solubility of membrane phospholipids in water (11). 

To provide the nutrients for proliferation of the spermatogonia and spermatocytes and maturation of the sperm. These are essential amino acids, glutamine and glucose as fuels and also as precursors for formation of nucleotides essential fatty acids for formation of phospholipids (for discussion of these topics, see Chapters 20 and 21). It is presumed that Sertoli cells extract these compounds from the blood. 

A procedure for determination of lipid hydroperoxides in human plasma is based on kinetic measurement of the CL of luminol (124) with hemin (75a) catalysis . CLD of microperoxidase-catalyzed oxidation of luminol (124) or isoluminol (190) was applied to detection and determination of amino acid hydroperoxides after exposure to UV and y-irradiation A method for determination of hydroperoxides in the phospholipids of cultured cells uses isoluminol (190) and microperoxidase as catalyst " . Simultaneous determination of phosphatidylcholine hydroperoxides and cholesteryl ester hydroperoxides in human serum is carried out by quantitative extraction of the lipids, HPLC separation by column switching and CLD using isoluminol (190) with microperoxidase catalysis . ... 

Pheromone (sex attractant). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Pheromone (signaling). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Phospholipidemic effect. Oil, administered to phospholipids transfer protein knockout (PLTPO)-deficient mice, produced an increase of phospholipids and free cholesterol in the VLDL-LDL region of PLTPO mice. Accumulation of phospholipids and free cholesterol was dramatically increased in PLTPO/HLO mice compared to PLTPO mice. Turnover studies indicated that coconut oil was associated with delayed catabolism of phospholipids and phospho-lipids/free cholesterol-rich particles. Incubation of these particles with hepatocytes of coconut-fed mice produced a reduced removal of phospholipids and free cholesterol by SRBI, even though SRBI protein expression levels were unchanged . 

Toxicity assessment. Ethanol extract of the leaf, administered intraperitoneally to mice, was active, LDjf, 0.75 g/kg"" " . Ethanol extract of the fresh leaf and stem, administered intraperitoneally to mice at the minimum toxic dose of 1 mL/animal, was active. Water extract of the fresh leaf and stem, administered intraperitoneally to mice at the minimum toxic dose of 1 mL/ animal, was active " . Aqueous extract of the husk fiber, administered orally to mice, was active, LDjf, 2.30 g/kgf" " . Tricarboxylate carrier influence. Oil, administered to rats at a dose of 15% of the diet for 3 weeks, produced a differential mitochondrial fatty acid composition and no appreciable change in phospholipids composition and cholesterol level. Compared with coconut oil-fed rats, the mitochondrial tricarboxylate carrier activity was markedly decreased in liver mitochondria from fish oil-fed rats. No difference in the Arrhenius plot between the two groups was observed "". 

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