Synthesis of structured lipids and etherlipids with antioxidants: combination of a selena fatty acid and a selena fatty alcohol with a carotenoic acid in glyceride molecules

Acylglycerols of Myristic Acid as New Candidates for Effective Stigmasterol Delivery-Design, Synthesis, and the Influence on Physicochemical Properties of Liposomes

New carriers of phytosterols; acylglycerols containing natural myristic acid at sn-1 and sn-3 positions and stigmasterol residue linked to sn-2 position by carbonate and succinate linker have been designed and synthesized in three-step synthesis from dihydroxyacetone (DHA). The synthetic pathway involved Steglich esterification of DHA with myristic acid; reduction of carbonyl group of 1,3-dimyristoylpropanone and esterification of 1,3-dimyristoylglicerol with stigmasterol chloroformate or stigmasterol hemisuccinate. The structure of the obtained hybrids was established by the spectroscopic methods (NMR; IR; HRMS). Obtained hybrid molecules were used to form new liposomes in the mixture with model phospholipid and their effect on their physicochemical properties was determined, including the polarity, fluidity, and main phase transition of liposomes using differential scanning calorimetry and fluorimetric methods. The results confirm the significant effect of both stigmasterol-containing acylglycerols on the hydrophilic and hydrophobic region of liposome membranes. They significantly increase the order in the polar heads of the lipid bilayer and increase the rigidity in the hydrophobic region. Moreover, the presence of both acylglycerols in the membranes shifts the temperature of the main phase transition towards higher temperatures. Our results indicate stabilization of the bilayer over a wide temperature range (above and below the phase transition temperature), which in addition to the beneficial effects of phytosterols on human health makes them more attractive components of novel lipid nanocarriers compared to cholesterol.

Heavy Atom Detergent/Lipid Combined X-ray Crystallography for Elucidating the Structure-Function Relationships of Membrane Proteins

Membrane proteins reside in the lipid bilayer of biomembranes and the structure and function of these proteins are closely related to their interactions with lipid molecules. Structural analyses of interactions between membrane proteins and lipids or detergents that constitute biological or artificial model membranes are important for understanding the functions and physicochemical properties of membrane proteins and biomembranes. Determination of membrane protein structures is much more difficult when compared with that of soluble proteins, but the development of various new technologies has accelerated the elucidation of the structure-function relationship of membrane proteins. This review summarizes the development of heavy atom derivative detergents and lipids that can be used for structural analysis of membrane proteins and their interactions with detergents/lipids, including their application with X-ray free-electron laser crystallography.

Synthesis, self-assembling and gene delivery potential of a novel highly unsaturated, conjugated cationic phospholipid

The synthesis and self-assembling properties of a model compound in a new class of cationic phospholipids with a highly unsaturated conjugated fatty acid are described. In addition, the potential of this new lipid as a nucleic acid carrier was evaluated through lipoplex formulations employing 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) as helper lipid with and without the polycationic peptide protamine, together with a plasmid DNA (pDNA). Lipoplexes composed of this novel unsaturated lipid exhibited pDNA binding and protection from DNase I degradation when formulated with protamine. The new cationic lipid revealed transfection efficiency comparable to the commercial reference 1,2-dimyristoyl-sn-glycero-3-ethylphophocholine (EPC) in Chinese hamster ovary-K1 (CHO-K1) cells and performed equally to the standard reference Lipofectamine 2000 when the formulation included protamine.

Hydrophilic carotenoids: surface properties and aggregation behavior of a highly unsaturated carotenoid lysophospholipid

The water dispersibility of a hydrophobic carotenoid has been greatly enhanced by using it as the acyl part in the synthesis of a highly unsaturated lysophospholipid. Dynamic light scattering has revealed the formation of stable aggregates with an average hydrodynamic radius of a few nanometers, and absorption spectra show that the aggregates can withstand the addition of ethanol or acetonitrile until the volume fraction of water falls below 70 and 62%, respectively. The properties of the carotenoid phospholipids have been characterized by determining surface tension, critical micelle concentration, surface concentration, molecular area, free energy of adsorption and micellation, adsorption-micellar energy relationship, and equilibrium constants.

Structured Lipids-Novel Fats with Medical, Nutraceutical, and Food Applications

Generally, structured lipids (SLs) are triacylglycerols (TAGs) that have been modified to change the fatty acid composition and/or their positional distribution in glycerol backbone by chemically and/or enzymatically catalyzed reactions and/or genetic engineering. More specifically, SLs are modified TAGs with improved nutritional or functional properties. SLs provide an effective means for producing tailor-made lipids with desired physical characteristics, chemical properties, and/or nutritional benefits. The production, commercialization outlook, medical, and food applications of SLs are reviewed here. Physical property measurements for SL in food systems and future research needs for increased industrial acceptance are also included in this review.

Action of 1-(11-selenadodecyl)-glycerol and 1-(11-selenadodecyl)-3-trolox-glycerol against lipid peroxidation

The antioxidant action on lipid peroxidation of the synthesized selenium compounds 1-(11-selenadodecyl)-glycerol (SeG) and 1-(11-selenadodecyl)-3-Trolox-glycerol (SeTrG, where Trolox = 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) was investigated. We compared the reactivity of the selenium compounds toward peroxyl radicals and their inhibitory effect on lipid peroxidation, induced by several kinds of initiating species such as azo compounds, metal ions, and superoxide/nitric oxide in solution, micelles, membranes, and rat plasma. SeTrG, but not SeG, scavenged peroxyl radicals. SeG reduced methyl linoleate hydroperoxides in organic solution and in methyl linoleate micelles oxidized by ferrous ion (Fe2+)/ascorbic acid. In rat plasma SeG and SeTrG decreased the formation of lipid hydroperoxides generated by hydrophilic azo compounds. SeG and SeTrG spared alpha-tocopherol (alpha-TOH) consumption in multilamellar vesicle membranes oxidized by hydrophilic or lipophilic initiators, and only SeTrG spared alpha-TOH in superoxide/nitric oxide oxidized membranes. In rat plasma oxidized by radical initiators (either hydrophilic or lipophilic) or superoxide/nitric oxide, SeTrG suppressed alpha-TOH consumption, but SeG had no effect. The two selenium-containing compounds showed inhibitory effects on lipid peroxidation that depended on their structure, the medium where they acted, and the oxidant used.