Search results for "Lecithin"
showing 10 items of 61 documents
Orientation and molecular contacts of melatonin confined into AOT and lecithin reversed micellar systems
2008
Abstract The state of increasing amounts of melatonin (MLT) confined in dry AOT or lecithin reversed micelles dispersed in CCl 4 has been investigated by UV–vis and 1 H NMR spectroscopies. The experimental results are consistent with MLT totally entrapped in reversed micelles, as a consequence of specific melatonin/surfactant interaction; the main driving force of the MLT solubilization in the core of reversed micelles is the establishment of H-bonding between the MLT NH groups (both indolic and amidic) and the head group of surfactants. The short contacts deduced from intermolecular NOEs are accounted for by favourable interactions between the surfactant's polar head and the H7–NH–H2 fragm…
Physicochemical investigation of acrylamide solubilization in sodium bis(2-ethylhexyl)sulfosuccinate and lecithin reversed micelles.
2003
The state of acrylamide confined within dry sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and lecithin reversed micelles dispersed in CCl4 has been investigated by FTIR and H-1 NMR spectroscopy. Measurements have been performed at 25 degreesC as a function of the acrylamide-to-surfactant molar ratio (R) at a fixed surfactant concentration (0.1 mol kg(-1)). The analysis of experimental data, corroborated by the results of SAXS measurements, is consistent with the hypothesis that acrylamide is quite uniformly distributed among reversed micelles mainly located in proximity to the surfactant head-group region and that its presence induces significant unidimensional growth of micellar aggregates.…
Lipid multilayered particles: the role of chitosan on structure and morphology
2010
Multilayered nanovectors made up from a controlled binary lipid mixture (POPC and DMPS) and trimethyl chitosan (TMC) have been prepared and characterized by light- and small angle neutron scattering. The morphology and the multilayer structure of the particle outer shell has been described in detail. By varying the amount of TMC in the starting solution it is possible to tune the overall surface particle charge as well as its multilamellarity. In this way the drug loading/release properties of the particles can be controlled. Therefore the use of controlled POPC/DMPS mixtures can be a valid alternative to commercial lecithin to obtain nanovectors with specific release properties.
Small-angle neutron scattering from lecithin reverse micelles
1996
Abstract We report new results of small-angle neutron scattering from cyclohexane- d 12 /lecithin/water micellar solutions, performed as a function of the water content, w 0 , the temperature, T and the dispersed-phase volume fraction, ф. The data from dilute samples can be interpreted in terms of the existence of giant cylindrical reverse micelles, in good agreement with the current idea of an unlimited micellar growth with ф. In contrast, the appearance of a sharp interference maximum at high concentrations ( ф > 0.15 ) suggests that the current hypothesis of a gel structure interpreted as a random network of entangled micelles can be assumed to be incorrect, and that there must be some c…
Identification of Abies sibirica L. Polyprenols and Characterisation of Polyprenol-Containing Liposomes
2020
The needles of conifer trees are one of the richest sources of natural polyprenols. Polyprenol homologs from Abies sibirica L. lipophilic 80% purified extract were analyzed and quantified. In total, 10 peaks (Prenol-11 to Prenol-20) were observed in the ultra-high-performance liquid chromatography&ndash
Spectroscopic and Structural Investigation of the Confinement of D and L Dimethyl Tartrate in Lecithin Reverse Micelles
2009
The confinement of D and L dimethyl tartrate in lecithin reverse micelles dispersed in cyclohexane has been investigated by FT-IR, polarimetry, electronic and vibrational circular dichroism (ECD and VCD), 1H NMR, and small-angle X-ray scattering (SAXS). Measurements have been performed at room temperature as a function of the solubilizate-to-surfactant molar ratio (R) at fixed lecithin concentration. The analysis of experimental data indicates that the dimethyl tartrate molecules are solubilized within reverse micelles in proximity to the surfactant head groups in the same way for the D and L forms. The encapsulation of dimethyl tatrate within lecithin reverse micelles involves changes in i…
The Impact of Propanol, N-Butanol and Pentanol on Aqueous Dispersions of Sonicated Liposomes. EPR Study
2022
Abstract This paper presents the effect of selected alcohols on the fluidity of liposome membranes obtained in sonication of DPPC lecithin. Using the EPR technique, the duality of propanol, n-butanol and pentanol on the behaviour of the aqueous dispersion of liposomes was demonstrated. It was shown that after exceeding a certain concentration, these alcohols initiate dispersion foaming, leading to phase separation: liposome dispersion - lipid foam. The influence of the shape of the molecule and the length of hydrocarbon chains on the effectiveness of destabilisation of the structure of lipid membranes was indicated.
Low Serum Choline Concentrations Are Associated with Worse Cognitive Performance in Subjects with Metabolic Syndrome
2020
OBJECTIVES: Choline is an essential nutrient critical for components of the cell membrane, such as choline-containing phospholipids (phosphatidylcholine and sphingomyelin), and in synthesis of the neurotransmitter acetylcholine. Choline has been shown to exert neuroprotective effects, but the association between serum choline and cognitive performance has been scarcely investigated. Our aims are: 1) To study the association between serum total choline, phosphatidylcholine and sphingomyelin with cognitive performance in subjects with metabolic syndrome; and 2) to analyze genetic variants and dietary intake most associated with cholines in this population. METHODS: We analyzed 426 subjects (a…
Platelet membrane fluidity and platelet membrane lipid pattern in essential hypertension
1995
In a group of subjects with essential hypertension platelets were studied in resting conditions: platelet membrane fluidity was measured with the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH), platelet membrane cholesterol/phospholipid ratio was evaluated separating the membrane lipids with column chromatography, and platelet membrane individual phospholipids were determined using two-dimensional thin-layer chromatography. From the obtained results, it is evident that platelet membrane fluidity does not differentiate normals from hypertensives; platelet membrane cholesterol/phospholipid ratio is increased in hypertensives, while of the platelet membrane individu…
Chapter 23: Choline, a precursor of acetylcholine and phospholipids in the brain
1993
Publisher Summary The plasma level of free choline is remarkably constant at about 10 pM in animals and human. Ingestion of food, especially when rich in choline or lecithin, transiently elevates the plasma choline level up to 20 pM or more. In contrast, choline-deficient diet leads to a reduction of the plasma level by about 50%. Choline is considered an essential nutrient, which is predominantly supplied as phosphatidylcholine (lecithin). For a long time, neuroscientists have been intrigued by the fact that choline is a precursor for the biosynthesis of both acetylcholine (ACh) and phospholipids. For 50 years, lecithin has been marketed in Europe as a drug that was claimed to prevent exha…