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PubMed1990

Isolation and purification of lecithin by preparative high-performance liquid chromatography.

Mixed-chain, multispecies, egg yolk-derived lecithin was isolated and purified on a silica column with isocratic elution. A method development column (20 x 0.46 cm I.D.) packed with YMC 15-30 microns, 120 A spherical silica and a mobile phase consisting of 5 mM ammonium acetate in acetonitrile-2-propanol-methanol-water (80:13:5:12) was used to separate the lecithin from other phospholipids. The mobile phase conditions for the method development system was adopted for two types of preparative HPLC systems: a Separations Technology SepTech NovaPrep 5000 system with a 20 x 1.93 cm I.D. column and a ST/800A system with a 20 x 5.00 cm I.D. Annular Expansion (A/E) column. The maximum load was 50 microliters of crude solution (2 mg) for the method development column, 0.90 ml (35 mg) for the 20 x 1.93 cm I.D. column and 6.0 ml (240 mg) for the 20 x 5.00 cm I.D. A/E column. The flow-rates were 2, 35 and 235 ml/min, respectively. The fractions collected from the preparative systems were analyzed for purity by analytical-scale high-performance liquid chromatography and by thin-layer chromatography with selective detection with molybdenum blue for phospholipids and detection of all organic compounds by sulfuric acid. Purity of the recovered lecithin was greater than 99%.

Chromatography, High Pressure Liquid↗
PubMed1977

Lecithin consumption raises serum-free-choline levels.

Consumption of choline by rats sequentially increases serum-choline, brain-choline, and brain-acetylcholine concentrations. In man consumption of choline increases in levels in the serum and cerebrospinal fluid; its administration is an effective way of treating tardive dyskinesia. We found that oral lecithin is considerably more effective in raising human serum-choline levels than an equivalent quantity of choline chloride. 30 minutes after ingestion of choline chloride (2-3 g free base), serum-choline levels rose by 86% and returned to normal values within 4 hours; 1 hour after lecithin ingestion, these levels rose by 265% and remained significantly raised for 12 hours. Lecithin may therefore be the method of choice for accelerating acetylcholine synthesis by increasing the availability of choline, its precursor in the blood.

Acetylcholine↗
PubMed1986

Postobstructive subcellular organelle and biliary lipid composition in the rat. A selective increase in biliary lecithin output is not reflected by changes in organelle composition.

Rats infused intravenously with taurocholate shortly after relief of 48 h of biliary obstruction excrete in bile twice as much phospholipid in relation to cholesterol and bile acid as controls. In an effort to identify a subcellular compartment as the source of this biliary lipid, we examined several hepatic subcellular organelles for an increase in phospholipid to cholesterol ratio or an increase in biliary-type lecithins (16:0-18:2; 16:0-20:4) either absolute or relative to non-biliary-type lecithins (18:0-20:4; 18:0-22:6) as analyzed by high-performance liquid chromatography. Subcellular fractions studied were: three microsomal subfractions, Golgi heavy and intermediate fractions, and plasma membrane light (canaliculus-enriched) fraction. No organelle fraction from rats with biliary obstruction displayed either a significant increase in phospholipid to cholesterol ratio or a relative or absolute increase in biliary type lecithin. This suggests that biliary lipid changes are not attributable to measurable alterations in lipid composition of any anatomical compartment in the liver cells; changes are probably more related to changes in lipid turnover than to organelle total lipid pool sizes.

Animals↗
PubMed1986

A quantitative dynamic concept of the interphase partition of lipids: application to bile salt-lecithin-cholesterol mixed micelles.

A system is proposed for a quantitative classification of lipids, based on interphase partition coefficients. This system enables calculation of exchanges of lipid molecules between phases. The mass/volume chemical unit mol X cm-3, strictly derived from the CGS system, is used, thus simplifying mathematical relations. Applied to bile salt-lecithin-cholesterol mixed micelles, this dynamic concept gives new insight into the variations of physico-chemical parameters. Experimental results obtained with the glycodesoxycholate and the taurocholate show a striking difference in partition coefficients between aqueous and mixed bile salt-lecithin interfacial phases. A new model applying triangular co-ordinates to a bile salt-lecithin-cholesterol mixed lipid phase is described.

Bile Acids and Salts↗
PubMed2001

Determination of the IgE-binding activity of soy lecithin and refined and non-refined soybean oils.

In the present study refined and non-refined soybean oils as well as soy lecithins were investigated for residual allergenicity and compared with extracts from native soybeans. By means of immunoblotting and EAST inhibition experiments no IgE-binding activity was detectable in refined soybean oils, which is probably due to thermal treatment during the refining. The investigated non-refined oils and soy lecithins showed a residual IgE-binding activity. In addition in the lecithin extracts a new IgE-binding structure with a molecular mass of approximately 16 kDa was detectable.

Blotting, Western↗
PubMed2001

Pharmacokinetic behavior of cyclosporin A in rabbits by oral administration of lecithin vesicle and Sandimmun Neoral.

The present study was undertaken to investigate the incorporation of lipophilic polypeptide, cyclosporin A (CsA) into lecithin vesicular system and to compare its pharmacokinetics behavior with Sandimmun Neoral (CsA-NEO). Lecithin vesicles of cyclosporin A (CsA-VES) were prepared by the rotary evaporation method, treated further with sonication. Studies were carried out to characterize the vesicles on physical properties, content, entrapment efficiency, particle size, polydispersity and Zeta potential. Pharmacokinetic behaviors were studied in rabbits at dose of 30 mg/kg. Results showed CyA vesicles were spherical particles, with content of 3.137+/-0.060% mg/ml, entrapment efficiency of 98.91+/-0.80%, particle size of 63.89+/-4.75 nm, polydispersity of 43.2+/-6.1% and Zeta potential of -13 mV. The best model fitting experimental data was a two-compartment open model with first-order kinetics. The relative bioavailability of CsA-VES versus CsA-NEO was 105+/-21% (n=6) and statistical analysis demonstrated both preparations were bioequivalent. In conclusion, lecithin vesicles are promising carriers in the oral delivery of CsA, considering their absorption enhancement effect and low-toxic property.

Administration, Oral↗
PubMed1982

Oral lecithin and linoleic acid in Friedreich's ataxia: II. Clinical results.

Twenty-two patients with Friedreich's Ataxia and ten normal controls were followed for one year and assessed as to their clinical performance after two successive six-month periods of lecithin or safflower oil. Results demonstrated no significant difference in performance scores according to group assignation, neither in patients nor in controls. According to stages, two patients in stage I and to a lesser degree, one patient in stage IV showed better scores for muscle strength and some motor accuracy and coordination tests with lecithin. Controls as groups maintained positive scores in all tests. Patients as groups showed negative mean values in nine out of eleven tests. Again as groups, patients receiving safflower oil demonstrated a mean 8% less deterioration than patients receiving lecithin. This study demonstrates that objective clinical tests and the participation of normal controls are a must in a therapeutic trial implicating patients with a progressive disorder such as Friedreich's Ataxia. The possible role of linoleic acid as the active factor from which clinical improvement proceeded in some specific patients and with early functional stages of the disease, has to be considered and reevaluated in the near future.

Administration, Oral↗
PubMed1993

Kinetic mechanism of lecithin retinol acyl transferase.

Lecithin retinol acyl transferase transfers acyl groups regiospecifically from the 1-position of lecithins to all-trans-retinol (vitamin A) and similar retinoids. LRAT is essential for the biosynthesis of 11-cis-retinal, the visual pigment chromophore, and is also required for the general dietary mobilization of vitamin A. The kinetic mechanism of this enzyme is described here, KM and Vmax values were determined for the substrates dipalmitoylphosphatidylcholine (DPPC) [1.38 microM and 0.17 microM/(min-mg), respectively] and for all-trans-retinol [0.243 microM and 0.199 microM/(min-mg), respectively]. In order to distinguish between a ping-pong bi-bi mechanism and a rapid equilibrium random or ordered bi-bi mechanism, the velocity of product formation as a function of one of the substrates at different fixed concentrations of the other substrate was measured. The parallel lines generated are entirely consistent with a ping-pong bi-bi mechanism in which DPPC first binds to LRAT and acylates it and rule out both simple random binding and ordered kinetic mechanisms. Further evidence for a ping-pong bi-bi mechanism comes from partial exchange reaction studies which show that LRAT can catalyze acyl group interchange between two different lecithin derivatives. Finally, the ping-pong reaction was established as being ordered, using the potent and reversible dead-end inhibitor 13-desmethyl-13,14-dihydro-all-trans-retinyl trifluoroacetate. This compound proved to be competitive with respect to DPPC, with a KI = 11.4 microM, and uncompetitive with respect to all-trans-retinol.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1985

Coexistence of simple and mixed bile salt-lecithin micelles: an NMR self-diffusion study.

The aggregation behavior of bile salt and lecithin in aqueous solutions at 20 degrees C was studied from bile salt, lecithin, and aggregate self-diffusion coefficients obtained by means of a Fourier-transform NMR pulsed-gradient spin-echo technique. The results strongly support the coexistence of simple bile salt micelles and mixed bile salt-lecithin micelles under physiologic conditions.

Bile Acids and Salts↗
PubMed2003

Production and characterization of O/W emulsions containing cationic droplets stabilized by lecithin-chitosan membranes.

Oil-in-water emulsions containing cationic droplets stabilized by lecithin-chitosan membranes were produced using a two-stage process. A primary emulsion was prepared by homogenizing 5 wt % corn oil with 95 wt % aqueous solution (1 wt % lecithin, 100 mM acetic acid, pH 3.0) using a high-pressure valve homogenizer. This emulsion was diluted with aqueous chitosan solutions to form secondary emulsions with varying compositions: 1 wt % corn oil, 0.2 wt % lecithin, 100 mM acetic acid, and 0-0.04 wt % chitosan (pH 3.0). The particle size distribution, particle charge, and creaming stability of the primary and secondary emulsions were measured. The electrical charge on the droplets increased from -49 to +54 mV as the chitosan concentration was increased from 0 to 0.04 wt %, which indicated that chitosan adsorbed to the droplet surfaces. The mean particle diameter of the emulsions increased dramatically and the emulsions became unstable to creaming when the chitosan concentration exceeded 0.008 wt %, which was attributed to charge neutralization and bridging flocculation effects. Sonication, blending, or homogenization could be used to disrupt flocs formed in secondary emulsions containing droplets with high positive charges, leading to the production of emulsions with relatively small particle diameters (approximately 1 microm). These emulsions had good stability to droplet aggregation at low pH (< or =5) and ionic strengths (<500 mM). The interfacial engineering technology utilized in this study could lead to the creation of food emulsions with improved stability to environmental stresses.

Chitin↗
PubMed1999

Identification of character impact odorants of different soybean lecithins.

The potent odorants of standardized, enzymatically hydrolyzed, and deoiled soybean lecithins were characterized systematically by combined gas chromatography/mass spectrometry and olfactometry. Sixty-one odorants were identified; 53 of these odor-active compounds have not previously been reported as odorants of soybean lecithin flavor. By aroma extract dilution analysis and modified combined hedonic and response measurement the following odorants showed the highest flavor dilution factors and CHARM values: (E,E)-2, 4-decadienal (deep-fried), (E)-beta-damascenone (apple-like), 2, 3-diethyl-5-methylpyrazine (roasty, earthy), (E)-2-nonenal (cardboard-like), trans-4,5-epoxy-(E)-2-decenal (metallic), 1-nonen-3-one (mushroom-like), 2-ethyl-3,5-dimethylpyrazine (roasty, earthy), and 1-octen-3-one (mushroom-like). Enzymatic hydrolysis intensified especially the roasty sensation of 2, 3-diethyl-5-methylpyrazine, whereas deoiling effected a general significant decrease in olfactory perception on the nitrogen-containing compounds. In addition, sensory profiles of nasal and retronasal lecithin odor were performed.

Chromatography, Gas↗
PubMed1999

Quantification and sensory studies of character impact odorants of different soybean lecithins.

Fifty-four potent odorants in standardized, hydrolyzed, and deoiled and hydrolyzed soybean lecithins were quantified by high-resolution gas chromatography/mass spectrometry (HRGC/MS). The characterization of their aroma impact was performed by calculation of nasal (n) and retronasal (r) odor activity values (OAVs). For this, the nasal and retronasal recognition thresholds of 18 odor-active compounds were determined in vegetable oil. The following compounds showed the highest nOAVs: 2,3-diethyl-5-methylpyrazine, methylpropanal, acetic acid, pentanoic acid, 2-ethyl-3,5-dimethylpyrazine, pentylpyridine, (Z)-1,5-octadien-3-one, 2-methylbutanal, and beta-damascenone. In addition to the compounds above, 1-octen-3-one, 1-nonen-3-one, and 3-methyl-2,4-nonandione showed potent rOAVs. The results of quantification and OAV calculation were confirmed by a model mixture of 25 impact odorants, which yielded a highly similar sensory profile to that of the original soybean lecithin. The sensory importance of pyrazines and free acids increased through enzymatic hydrolysis and decreased by the process of deoiling. The impact of unsaturated ketones on the lecithin aroma was not changed by either process.

Gas Chromatography-Mass Spectrometry↗
PubMed2000

Conversion to docosahexaenoic acid-containing phosphatidylserine from squid skin lecithin by phospholipase D-mediated transphosphatidylation.

Phospholipase D (PLD)-mediated transphosphatidylation of squid skin lecithin with L-serine was examined to prepare docosahexaenoic acid-containing phosphatidylserine (DHA-PS). When a biphasic system with organic solvent and 0.2 M acetate buffer (pH 5.5) was used, PS synthesis was significantly affected by the amount of 3.4 M L-serine-containing acetate buffer. L-Serine concentration in the acetate buffer and choice of organic solvent were also crucial. In a typical reaction with 0.8 unit of PLD (Streptomyces sp.), 2.5 mL of ethyl acetate substrate solution containing 30 mg of squid skin lecithin in combination with 3 mL of 3.4 M L-serine-containing 0.2 M acetate buffer (pH 5.5), PS content in the recovered phospholipid fraction increased to 43.1% after 24 h. DHA composed 37.6% of fatty acids in the converted PS. This was the same DHA level as in the substrate. Phosphatidylcholine (squid skin PC, DHA 44.2%) in the squid skin lecithin was more effectively converted to PS than phosphatidylethanolamine.

Animals↗
PubMed2000

Effect of dietary lipid (soybean lecithin and triacylglycerol) on hepatic F-actin microfilaments in cyclosporine A-treated rats: image analysis by confocal laser scanning microscopy.

We studied and quantified the effect of cyclosporine A on hepatic F-actin on bile canalicular and basolateral membranes in rats fed either soybean lecithin, triacylglycerol-enriched diet, or low-fat diet by means of confocal laser scanning microscopy imaging. The phalloidin-FITC staining of F-actin was quite normal in the lecithin-cyclosporine A group but decreased significantly in the other cyclosporine A-treated groups (by 40% and 25% of control in triacylglycerol-cyclosporine A and cyclosporine A groups, respectively). The alteration of F-actin by cyclosporine A, related to cholestasis evidenced by a decrease in bile salt secretion, was prevented by dietary soybean lecithin and amplified by dietary soybean triacylglycerol.

Actins↗
PubMed2001

Lyophilized lecithin based oil-water microemulsions as a new and low toxic delivery system for amphotericin B.

PURPOSE: To develop and investigate lecithin based oil-water microemulsions as potential amphotericin B (AmB) delivery systems and to evaluate their in vivo acute toxicity. METHODS: AmB was added to the microemulsion and its location was evaluated by partitioning studies and UV-visible spectrophotometric analysis of the drug. Both, non-lyophilized and reconstituted microemulsions were characterised and assessed for their stability. Single-dose acute toxicity of the AmB microemulsion was studied on male albino Webster-derived CD-1 mice and compared with Fungizone. RESULTS: The studies performed showed that AmB was intercalated on the oil-water interface of the microemulsion as a complex formed with lecithin molecules. AmB addition did not seem to modify the rheological properties of the original system, but had an effect on its particle size distribution. Lyophilization of the microemulsion led to an oily cake, easily reconstituted and stable at the conditions studied. Single-dose acute toxicity studies proved that the LD50 of AmB microemulsions was of 4 mg kg(-1) of animal weight, compared with 1 mg kg(-1) found for Fungizone. CONCLUSIONS: Lyophilized lecithin based oil-water microemulsions appear to be valuable systems for the delivery of AmB in terms of easy and low-cost manufacturing, stability and safety compared with the formulations already in market.

Amphotericin B↗
PubMed1998

Extracellular and intracellular regulation of biliary lecithin hydrophobicity.

Bromosulfophthalein and papaverine have been demonstrated to inhibit biliary lipid secretion without affecting secretion of bile salts in normal rats, so-called uncoupling. Bromosulfophthalein inhibits the capacity of intracanalicular bile salt micelles to induce biliary lipid secretion, and papaverine inhibits vesicular transport within the hepatocyte. We compared the effects of bromosulfophthalein and papaverine on biliary lipid secretion in normal Sprague-Dawley rats and Eizai hyperbilirubinuria rats. The fatty acyl chain saturation in biliary lecithin increased during bromosulfophthalein infusion and decreased during papaverine infusion in Sprague-Dawley rats. Bromosulfophthalein had no effect on biliary lipid secretion in Eizai rats, while papaverine induced uncoupling. The degree of fatty acyl chain saturation in biliary lecithin was unchanged during bromosulfophthalein infusion, but decreased with papaverine in Eizai rats. We deduce that selection of biliary lecithin species occurs at various points in the lipid transport pathway at intracellular and intracanalicular sites.

Animals↗
PubMed2003

Unique inhibition of bile salt-induced apoptosis by lecithins and cytoprotective bile salts in immortalized mouse cholangiocytes.

Bile duct epithelium is physiologically exposed to high concentrations of bile salts, suggesting the presence of a cytoprotective mechanism(s). The aim of this study was to clarify whether bile salts cause bile duct cell damage and to elucidate the mechanism(s) providing protection against such an action of bile salts. Immortalized mouse cholangiocytes were incubated with taurocholate, taurochenodeoxycholate, glycochenodeoxycholate (GCDC), taurodeoxycholate, and tauroursodeoxycholate (TUDC), followed by flow-cytometric analysis and caspase activity assay to evaluate the induction of apoptosis. GCDC time-dependently induced caspase 3 (3.4-fold)- and caspase 9 (1.4-fold)-mediated apoptosis of cholangiocytes, but this was inhibited by lecithins and TUDC. Further, expression of cholangiocyte bile salt transporters (apical sodium-dependent bile salt transporter [Asbt] and multidrug resistance protein 3 [Mrp3]) was examined by RT-PCR and western blotting, and cholangiocyte bile salt uptake was determined using radiolabeled bile salts. Expression of cholangiocyte Asbt and Mrp3 was increased by bile salts, whereas lecithins interestingly reduced bile salt uptake to inhibit cholangiocyte apoptosis. In conclusion, bile salts themselves cause cholangiocyte apoptosis when absorbed by and retained inside the cell, but this is inhibited by washing out cytotoxic bile salts according to Mrp3, a rescue exporting molecule. Biliary lecithin is seemingly another cytoprotective player against cytotoxic bile salts, reducing their uptake, and this is associated with a reduced expression of Mrp3.

Animals↗
PubMed1966

The proportions of different lecithins in the livers of rats deficient in essential fatty acids.

1. Lecithin was prepared from the livers of rats deficient in essential fatty acids and analysed by means of countercurrent distribution. Thin-layer chromatography showed that only lecithin was present. 2. The distributions of phosphorus and the fatty acids at the 3 and 2 positions were determined. 3. It has been shown that 26% of the fatty acids in the 3 position were unsaturated and that most of the Delta(5,8,11)-eicosatrienoic acid and the arachidonic acids occur as the stearoyl or oleoyl lecithins.

Animals↗