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Photis Dais - One of the best experts on this subject based on the ideXlab platform.
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determination of the Diglyceride content in greek virgin olive oils and some commercial olive oils by employing 31 p nmr spectroscopy
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Penelope Fronimaki, Apostolos Spyros, Stella Christophoridou, Photis DaisAbstract:In this study, the Diglyceride contents of 96 samples of virgin olive oils from the regions of Crete, Lesvos, Messinia, Pilion, Zakynthos, Halkidiki, and Ilia, 15 samples of commercial extra virgin and pure olive oils, and 3 samples each of refined olive oils and pomace oils were determined by a facile method introduced in a previous publication. This method is based on the phosphitylation of the free hydroxyls of the Diglycerides with 2-chloro-4,4,5,5-tetramethyldioxaphospholane and the integration of the appropriate peaks in the (31)P NMR spectra. This preliminary study showed interesting trends in the Diglyceride content of the virgin olive oils from the various regions of Greece that can be used as simple criteria to assess the olive oil characteristics. Analysis of variance has been carried out for the Diglyceride content of each region in an attempt to detect possible differences in the Diglyceride levels among the various regions. Finally, the relationship between the ratio of 1,2-Diglycerides to the total amount of Diglycerides and the total amount of Diglycerides has been used to monitor the quality of virgin olive oils, commercial olive oils, refined olive oils, and pomace oils.
J.i. Di Cosimo - One of the best experts on this subject based on the ideXlab platform.
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Diglyceride-rich oils from glycerolysis of edible vegetable oils
Catalysis Today, 2018Co-Authors: Cristián Alejandro Ferretti, M.l. Spotti, J.i. Di CosimoAbstract:Abstract The human metabolism of 1,3-Diglyceride is believed to occur through a pathway that avoids re-synthesis of triglycerides and the consequent fat deposit in the body tissues. The synthesis of healthy vegetable oils with reduced triglyceride content was investigated using food production-compatible MgO as basic catalyst. The partial conversion of the triglycerides present in commercial edible oils into Diglycerides was carried out by glycerolysis. After optimizing the reaction conditions such as temperature, glycerol/triglyceride ratio, and inert gas flow rate, triglyceride conversions of up to 70% were reached after 8 h as well as a product containing 54% of Diglycerides, 67% of which is the healthier 1,3-isomer.
Richard W. Gross - One of the best experts on this subject based on the ideXlab platform.
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Multidimensional mass spectrometry-based shotgun lipidomics analysis of vinyl ether Diglycerides
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Kui Yang, Christopher M. Jenkins, Beverly Dilthey, Richard W. GrossAbstract:Diglycerides play a central role in lipid metabolism and signaling in mammalian cells. Although diacylglycerol molecular species comprise the majority of cellular Diglycerides that are commonly measured using a variety of approaches, identification of extremely low abundance vinyl ether Diglycerides has remained challenging. In this work, representative molecular species from the three Diglyceride subclasses (diacyl, vinyl ether, and alkyl ether Diglycerides; hereafter referred to as diradylglycerols) were interrogated by mass spectrometric analysis. Product ion mass spectra of the synthesized diradylglycerols with varied chain lengths and degrees of unsaturation demonstrated diagnostic fragmentation patterns indicative of each subclass. Multidimensional mass spectrometry-based shotgun lipidomics (MDMS-SL) analysis of mouse brain and heart lipid extracts were performed using the identified informative signature product ions. Through an array of tandem mass spectrometric analyses utilizing the orthogonal characteristics of neutral loss scanning and precursor ion scanning, the differential fragmentation of each subclass was exploited for high-yield structural analyses. Although molecular ion mass spectra readily identified diacylglycerol molecular species directly from the hexane fractions of tissue extracts enriched in nonpolar lipids, molecular ion peaks corresponding to ether-linked Diglycerides were not observable. The power of MDMS-SL utilizing the tandem mass spectrometric array analysis was demonstrated by identification and profiling of individual molecular species of vinyl ether Diglycerides in mouse brain and heart from their undetectable molecular ion peaks during MS^1 analysis. Collectively, this technology enabled the identification and profiling of previously inaccessible vinyl ether Diglyceride molecular species in mammalian tissues directly from extracts of biologic tissues. Graphical Abstract ᅟ
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Metabolism of ether-linked Diglycerides in brain and myocardium.
Methods in enzymology, 1992Co-Authors: David A. Ford, Richard W. GrossAbstract:Publisher Summary This chapter discusses the metabolism of ether-linked Diglycerides in brain and myocardium. The fundamental differences between ether-linked and diacyl phospholipids are also described. The chapter also discuses methods for quantitating ether-linked Diglycerides in mammalian cells and to assess the biochemical pathways responsible for ether-linked Diglyceride metabolism utilizing synthetic ether-linked Diglycerides purified by high-performance liquid chromatography (HPLC). The synthesis of specific molecular species of ether-linked Diglycerides is accomplished through utilization of appropriate subclasses or individual molecular species of lysophospholipid or monoradylglycerol precursors. These precursors can be specifically acylated with the desired fatty acid at the sn -2 position (for lysophospholipids) or sequentially acylated at the sn -3 and sn -2 positions (for monoradylglycerols) prior to their enzymatic conversion to ether-linked Diglycerides. Ether-linked Diglycerides can subsequently be purified by thin-layer chromatography (TLC), straight-phase HPLC, or both, to yield substantial amounts (10–100 mg) of homogeneous ether-linked Diglycerides.
Penelope Fronimaki - One of the best experts on this subject based on the ideXlab platform.
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determination of the Diglyceride content in greek virgin olive oils and some commercial olive oils by employing 31 p nmr spectroscopy
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Penelope Fronimaki, Apostolos Spyros, Stella Christophoridou, Photis DaisAbstract:In this study, the Diglyceride contents of 96 samples of virgin olive oils from the regions of Crete, Lesvos, Messinia, Pilion, Zakynthos, Halkidiki, and Ilia, 15 samples of commercial extra virgin and pure olive oils, and 3 samples each of refined olive oils and pomace oils were determined by a facile method introduced in a previous publication. This method is based on the phosphitylation of the free hydroxyls of the Diglycerides with 2-chloro-4,4,5,5-tetramethyldioxaphospholane and the integration of the appropriate peaks in the (31)P NMR spectra. This preliminary study showed interesting trends in the Diglyceride content of the virgin olive oils from the various regions of Greece that can be used as simple criteria to assess the olive oil characteristics. Analysis of variance has been carried out for the Diglyceride content of each region in an attempt to detect possible differences in the Diglyceride levels among the various regions. Finally, the relationship between the ratio of 1,2-Diglycerides to the total amount of Diglycerides and the total amount of Diglycerides has been used to monitor the quality of virgin olive oils, commercial olive oils, refined olive oils, and pomace oils.
Robert R. Rando - One of the best experts on this subject based on the ideXlab platform.
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The stereochemical requirement for protein kinase C activation by 3-methylDiglycerides matches that found in naturally occurring tumor promoters aplysiatoxins.
FEBS letters, 1990Co-Authors: Fanhua Kong, Yoshito Kishi, Dolores Pérez-sala, Robert R. RandoAbstract:Abstract Protein kinase C is stereospecifically activated by, sn -1,2-(S)-Diglycerides. A second chiral center was introduced into the Diglycerides by preparing the 3-methyl derivatives. The activation of protein kinase C was also stereospecific with respect to the new chiral center established at the C3 position of the methylated Diglycerides. The stereospecificity of protein kinase C directed towards the C2 and C3 positions of the Diglycerides is matched in the analogous C29 and C30 stereocenters of the tumor promoting debromoaplysiatoxins. This finding strengthens the view that the structurally diverse tumor promotors contain the embedded Diglyceride-like pharmacophore.