- FT-IR and NMR studies on the conformational and structural properties of 1,2-dipalmitoyl-sn-glycero-3-phosphatidyloligoglycerols
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The conformational behavior of membranes derived from a new class of phospholipids, 1,2-dipalmitoyl-sn-glycero-phosphatidyloligoglycerols DPPGx, is studied for the first time by FT-IR spectroscopy in the liquid crystalline and gel state. The phospholipids examined here are characterized by oligoglycerol chains of variable length in the headgroup, ranging from one (x = 1, DPPG1 = DPPG) to four glycerol units (x = 4, DPPG4). The transition from the gellike to the liquid crystalline phase is monitored via CH2 and CD2 stretching bands as well as CH2 wagging band progressions. CH2 wagging bands are used to determine the relative amounts, i.e., integral values over the whole chains, of kink/gauche-trans-gauche, double gauche, and end gauche conformers in the acyl chain region. Information about the absolute amount of gauche conformers at a specific chain segment is obtained by a quantitative analysis of the CD2 rocking band region for phospholipid samples with selectively deuterated acyl chains. These latter data are combined with the results from an independent 2H NMR study on the same compounds, which allows a distinction between the overall chain order and the local conformational order of the phospholipid chains. In addition, results from solid state 31P and 13C NMR studies are presented which provide additional support for the conclusions based on the FT-IR data. The present work clearly shows that the conformational and structural properties strongly depend on the headgroup structure and hydrophilicity, sample composition as well as sample temperature. The derived data are discussed by considering related phospholipid systems, such as DPPC, to demonstrate the particular impact of the headgroup length and hydrophilicity on the ordering characteristics of the acyl chains.
- Lehnert, Reneì?,Eibi, Hans-Joì?rg,Muì?ller, Klaus
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- Polyelectrolyte adsorption on heterogeneously charged surfaces
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The adsorption transition of a uniformly charged polyelectrolyte onto heterogeneously charged surfaces has been investigated using off-lattice Monte Carlo simulations. Each of these surfaces contains both positive and negative charges. In addition to the usual case of adsorption of a polyelectrolyte to a surface with net charge opposite to that of the polymer, we show that a polyelectrolyte can adsorb onto a surface with net surface charge density similar to that of the polyelectrolyte. This adsorption is caused by the spatial inhomogeneity of the surface charges, which creates attractive regions with charge density different from the overall charge density of the surface. The spatial inhomogeneity of the surface charges also leads to differences in the conformation of the adsorbed polyelectrolyte. The critical conditions of strength and range of electrostatic interactions and chain length necessary for adsorption of a polyelectrolyte to a heterogeneously charged surface are demonstrated.
- Ellis,Kong,Muthukumar
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- Preparation method of dipalmitoyl phosphatidylcholine
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The invention belongs to the technical field of compound preparation, and particularly relates to a dipalmitoyl phosphatidylcholine preparation method, which comprises: step 1, carrying out a condensation reaction on GPC and palmitic acid in the presence of an organic solvent, a condensation reagent and an organic alkali to generate a DPPC crude product solution; step 2, filtering the DPPC crude product solution, taking filtrate, stirring in a non-polar solvent I, filtering, taking filtrate, and concentrating; wherein the non-polar solvent I is one or more of petroleum ether, normal hexane andcyclohexane; step 3, pulping and filtering the crude product prepared in the step 2 in a mixed solvent II, taking a filter cake, repeatedly pulping and filtering, and drying the filter cake to obtaina white powder solid; wherein the mixed solvent II is a mixed solvent of acetone/butanone; and step 4, re-crystallizing the powder solid twice by using a mixed solvent III; wherein the mixed solventIII is a butanone/isopropanol mixed solvent. The preparation and purification process is easy to operate, a hot-pressing filtration process is not needed, the requirement on production equipment is not high, and the finally obtained product is high in yield and purity.
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Paragraph 0008; 0021-0036
(2020/05/05)
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- Synthesis and biological evaluation of novel phosphatidylcholine analogues containing monoterpene acids as potent antiproliferative agents
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The synthesis of novel phosphatidylcholines with geranic and citronellic acids in sn-1 and sn-2 positions is described. The structured phospholipids were obtained in high yields (59-87%) and evaluated in vitro for their cytotoxic activity against several cancer cell lines of different origin: MV4-11, A-549, MCF-7, LOVO, LOVO/DX, HepG2 and also towards noncancer cell line BALB/3T3 (normal mice fibroblasts). The phosphatidylcholines modified with monoterpene acid showed a significantly higher antiproliferative activity than free monoterpene acids. The highest activity was observed for the terpene-phospholipids containing the isoprenoid acids in sn-1 position of phosphatidylcholine and palmitic acid in sn-2.
- Gliszczyńska, Anna,Niezgoda, Natalia,G?adkowski, Witold,Czarnecka, Marta,?witalska, Marta,Wietrzyk, Joanna
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- Synthesis of phosphatidylcholine with conjugated linoleic acid and studies on its cytotoxic activity
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Phospholipids with conjugated linoleic acid (CLA), which are potential lipid prodrugs, were synthesised. CLA was obtained by the alkali-isomerisation of linoleic acid and was subsequently used in the synthesis of 1,2-di(conjugated)linoleoyl-sn-glycero-3-phosphocholine in good (82%) yield. 1-Palmitoyl-2-(conjugated)linoleoyl-sn-glycero-3-phosphocholine was obtained by a two-step synthesis in 87% yield. All the compounds were tested in an in vitro cytotoxicity assay against two human cancer cell lines, HL-60 and MCF-7, and a mouse fibroblast cell line, Balb/3T3. The free form of CLA exhibited the highest activity against all cancer cell lines. Results obtained for the Balb/3T3 line proved that phosphatidylcholine derivatives decreased the cytotoxic effect of CLA against healthy cell lines.
- Niezgoda, Natalia,Mitula, Pawel,Kempinska, Katarzyna,Wietrzyk, Joanna,Wawrzenczyk, Czeslaw
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p. 354 - 361
(2013/05/22)
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- Synthesis of dehydroepiandrosterone analogues modified with phosphatidic acid moiety
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Dehydroepiandrosterone (DHEA) and its metabolite 7α-OH DHEA have many diverse physiological, biological and biochemical effects encompassing various cell types, tissues and organs. In in vitro studies, DHEA analogues have myriad biological actions, but in vivo, especially in oral administration, DHEA produces far more limited clinical effects. One of the possible solutions of this problem is conversion of DHEA to active analogues and/or its transformation into prodrug form. In this article, the studies on the conversion of DHEA and 7α-OH DHEA into their phosphatides by the phosphodiester approach are described. In this esterification, N,N-dicyclohexylcarbodiimide (DCC) was the most efficient coupling agent as well as p-toluenesulphonyl chloride (TsCl).
- Smuga, Damian A.,Smuga, Ma?gorzata,?wizdor, Alina,Panek, Anna,Wawrzeńczyk, Czes?aw
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experimental part
p. 1146 - 1152
(2010/11/03)
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- Synthesis of phosphatidylcholine: An improved method without using the cadmium chloride complex of sn-glycero-3-phosphocholine
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An improved safe method that does not contaminate the environment with cadmium chloride, a toxic heavy metal salt, was developed for the synthesis of phosphatidylcholine (PC). PC was synthesized from sn-glycero-3-phosphocholine (GPC) and fatty acid in one step under mild conditions without the use of cadmium chloride. GPC was prepared from egg yolk PC and adsorbed by kieselguhr in a Teflon vessel. The GPC on kieselguhr was acylated with fatty acid in the presence of two reagents, dicyclohexylcarbodiimide for synthesis of fatty acid anhydride and 4-dimethylaminopyridine as an acylating catalyst, at 30°C overnight. The PC thus produced was purified by silica gel column chromatography. The yield of dioleoyl PC was 90% based on the starting material, GPC.
- Ichihara, Ken'ichi,Iwasaki, Hitomi,Ueda, Kaori,Takizawa, Ryoko,Naito, Hideko,Tomosugi, Mitsuhiro
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- A new approach to the stereospecific synthesis of phospholipids. The use of L-glyceric acid for the preparation of diacylglycerols, phosphatidylcholines, and related derivatives
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A new stereospecific synthesis of phospholipid derivatives of 1,2- diacyl-sn-glycerols is reported. The synthesis is based on (1) the use of L- glyceric acid as the stereocenter for construction of the optically active phospholipid molecule, (2) preparation of 3-triphenylmethyl-sn-glycerol as the key intermediate for sequential introduction of the primary and secondary acyl functions leading to the chiral diglycerides, and (3) elaboration of the sn-3-phosphodiester headgroup via phosphorylation using 2-chloro-2-oxo-1,3,2- dioxaphospholane, followed by ring opening of the five-membered phosphorus heterocycle with trimethylamine, ammonia, as well as oxygen and sulfur nucleophiles. The sequence has been shown to be suitable for the preparation of both symmetric and mixed-chain diacylglycerols with saturated and unsaturated acyl substituents. Phospholipid headgroups including phosphocholine, phosphoethanolamine, phosphoethanol, and phosphoethylthioacetate functions have been prepared. Application of the method to the synthesis of functionalized phosphatidylcholines has also been demonstrated by incorporating spectroscopically active spin-labeled and fluorescent reporter groups via postsynthetic derivatization of chain terminal ω-aminoalkyl functions of the acyl substituents of the compounds. The synthetic methods developed have a great deal of flexibility, providing convenient routes to a wide range of structurally variable phospholipids for physicochemical, enzymological, and cell-biological studies.
- Roodsari, Farzaneh S.,Wu, Dongpei,Pum, Gregory S.,Hajdu, Joseph
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p. 7727 - 7737
(2007/10/03)
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- Synthesis of a small library of mixed-acid phospholipids from D-mannitol as a homochiral starting material
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Synthesis of a series of mixed-acid phospholipids containing a polyunsaturated fatty acid using a newly protecting strategy are described. Thus, benzyl and methyl α-(2,4-dinitrophenyl)acetic acid which were respectively removed by BCl3 and 354 nm light are used as protecting groups.
- Xia, Jie,Hui, Yong-Zheng
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p. 1659 - 1663
(2007/10/03)
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- Method for producing liposomes with increased percent of compound encapsulated
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The efficiency of encapsulating a drug into a liposomal formulation is increased by use of a lipid having a carbon chain containing from about 13 to about 28 carbons during preparation of the liposomes. Preferably the liposomes are multivesicular liposomes.
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- Syntheses of 1,2-di-O -palmitoyl-sn -glycero-3-phosphocholine (DPPC) and analogs with 13C- and 2H-labeled choline head groups
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The syntheses of four head group labeled analogs of 1,2-di-O-palmitoyl-sn-glycero-3-phosphoc (DPPC) (6) by a general method from 1,2-di-O-palmitoyl-sn -glycero-3-phosphatidic acid (5) have been performed. The syntheses of 1,2-di-O-palmitoyl-sn-glycero-3-phospho[α-13C]choline (6a) and 1,2-di-O-palmitoyl-sn-glycero-3-phospho[β13C]choline (6b) were performed from labeled [l-13C]glycine (1a) in 52% overall yield and from [2-13C]glycine (1b) in 56% overall yield, respectively. 1,2-Di-O-palmitoyl-sn-glycero-3-phosphol[N(C2H3)3]choline (9) was prepared from 2-aminoethanol in 39% overall yield. 1,2-Di- O-palmitoyl-sn-glycero-3-phospho[α-C2H2]choline (12) was prepared from N,N-dimethylglycine ethyl ester in 50% overall yield.
- Lin, Sonyuan,Duclos Jr., Richard I.,Makriyannis, Alexandros
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p. 171 - 181
(2007/10/03)
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- Facile and useful synthesis of enantiomeric phosphatidylcholines
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The synthesis of optically active phosphatidylcholines (D- and L-4) containing two of the same fatty acid moieties in a molecule is described. Optically pure D-enantiomers (D-4) were obtained from 2,3-di-O-acyl-sn- glycerol (D-1) in high yield by phosphorylation with phosphorus oxychloride and subsequent treatment with choline tosylate (11a). L-Enantiomers (L-4) were also prepared in a similar manner from 1,2-di-O-acyl-sn-glycerol (L-1). The whole procedure is easy and useful for the synthesis of enantiomeric phosphatidylcholines.
- Ishihara, Masami,Sano, Atsunori
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p. 1096 - 1098
(2007/10/03)
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- Optically active oxiranes. Synthesis of PAF (Platelet Aggregating Factor)
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A number of epoxides bearing no function in the α-position have been converted into β-hydroxy sulfonium salts.Association with an otically active acid (dibenzoyltartaric) allowed the resolution.This method has been used to prepare the optically active glycidol octadecyl ether which was converted into (-) PAF. Key words: oxiranes / resolution / PAF synthesis
- Cimetiere, B,Jacob, L,Julia, M
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p. 926 - 938
(2007/10/02)
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- A General Method for the Synthesis of Glycerophospholipids and Their Analogues via H-Phosphonate Intermediates
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A general chemical method for the synthesis of glycerophospholipids and their analogues via H-phosphonate intermediates has been developed.It was found that 1,2-dipalmitoylglycero-3-H-phosphonate, prepared by the reaction of 1,2-dipalmitoylglycerol with PCl3/imidazole, reacts with various hydroxylic components (choline tosylate, N-(tert-butoxycarbonyl)ethanolamine, N-(tert-butoxycarbonyl)-L-serine) in the presence of condensing agents to produce in high yield the corresponding glycero-3-H-phosphonate diesters.These can be converted into natural phospholipids via oxidation with iodine or into thio or seleno analogues by using sulfur or selenium as oxidant, respectively.
- Lindh, Ingvar,Stawinski, Jacek
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p. 1338 - 1342
(2007/10/02)
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- Polymerized Phosphatidylcholine Vesicles. Synthesis and Characterization
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The synthesis and characterization of photopolymerized vesicles derived from bis-L-α-phosphatidylcholine (3) 1--2-palmitoyl-L-α-phosphatidylcholine (4), and 1-palmitoyl-2--L-α-phosphatidylcholine (5) are described.Ultrasonic irradiation of 3, 4, 5, 20percent 3 + 80percent 4, and 20percent 3 + 80percent 5 in water at 50 deg C yields opalescent to optically clear dispersions.Electron microscopy, entrapment of sucrose, and permeability measurements provide strong evidence for closed multilamellar vesicles having diameters ranging between 350 and 1400 Angstroem.Fourier transform 1H NMR spectra of the aqueous dispersions as well as IR spectra of chloroform extracts establish that no significant lipid decomposition occurs during vesicle preparation.Direct UV irradiation (254 nm) produces polymerized analogues of similar size and shape which (1) entrap sucrose, (2) show reduced permeability, and (3) exhibit enchanced stability.
- Regen, Steven L.,Singh, Alok,Oehme, Guenter,Singh, Maninder
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p. 791 - 795
(2007/10/02)
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