51 research outputs found
Ionic liquids as Additives in the Pig Liver Esterase (PLE) Catalyzed Synthesis of Chiral Disubstituted Malonates
No full textWallert S, Drauz K, Grayson I, Gröger H, Dominguez de Maria P, Bolm C. Ionic liquids as Additives in the Pig Liver Esterase (PLE) Catalyzed Synthesis of Chiral Disubstituted Malonates. Green Chem. 2005;7(8):602-605
Enzymatische Reaktionen in Gegenwart ionischer Additive
No full textWallert S, Grayson JI, Drauz K, et al. Enzymatische Reaktionen in Gegenwart ionischer Additive. 2005
Long-Chain Metabolites of Vitamin E: Metabolic Activation as a General Concept for Lipid-Soluble Vitamins?
No full textVitamins E, A, D and K comprise the class of lipid-soluble vitamins. For vitamins A and D, a metabolic conversion of precursors to active metabolites has already been described. During the metabolism of vitamin E, the long-chain metabolites (LCMs) 13′-hydroxychromanol (13′-OH) and 13′-carboxychromanol (13′-COOH) are formed by oxidative modification of the side-chain. The occurrence of these metabolites in human serum indicates a physiological relevance. Indeed, effects of the LCMs on lipid metabolism, apoptosis, proliferation and inflammatory actions as well as tocopherol and xenobiotic metabolism have been shown. Interestingly, there are several parallels between the actions of the LCMs of vitamin E and the active metabolites of vitamin A and D. The recent findings that the LCMs exert effects different from that of their precursors support their putative role as regulatory metabolites. Hence, it could be proposed that the mode of action of the LCMs might be mediated by a mechanism similar to vitamin A and D metabolites. If the physiological relevance and this concept of action of the LCMs can be confirmed, a general concept of activation of lipid-soluble vitamins via their metabolites might be deduced
Long-chain metabolites of vitamin E: Interference with lipotoxicity via lipid droplet associated protein PLIN2
No full textStructure-function relationship studies in vitro reveal distinct and specific effects of long-chain metabolites of vitamin E
No full textSCOPE: Cytochrome-dependent metabolism of vitamin E initially forms the long-chain metabolites (LCM) 13'-hydroxychromanols (13'-OH) and 13'-carboxychromanols (13'-COOH), which occur in human blood. Little is known about their biological functions.
MATERIAL AND RESULTS: A structure-activity relationship study using α- and δ-tocopherol (TOH), their LCM (α-13'-OH, δ-13'-OH, α-13'-COOH, and δ-13'-COOH) and representatives of their substructures (α-carboxyethylhydroxychromanol and pristanic acid) is performed to unravel critical structural elements of the LCM for biological activity. Prominent effects are mediated by α- and δ-LCM, as scavenger receptor cluster of differentiation 36 (CD36) expression is induced in human THP-1 macrophages and lipopolysaccharide-stimulated inducible nitric oxide synthase (iNos) expression is inhibited in murine RAW264.7 macrophages, while the other molecules are less or not effective.
CONCLUSION: The LCM effects depend on the presence of the chromanol ring system and on the modification of the side-chain but not on the substitution pattern of the chromanol ring. Therefore, it can be concluded that for mediation of effects by LCM the entire molecule is needed and that the effects are specific. Wepropose the LCM of the micronutrient vitamin E as a new class of regulatory metabolites, but further studies are needed to corroborate this hypothesis
Beta1-integrin-EGFR crosstalk regulation of invadopodia proteolytic function through NHE1 phosphorylation: RSK and ROCK
No full textAnalytical strategies to assess the functional metabolome of vitamin E
No full textAfter more than 90 years from its discovery and thousands of papers published, the physiological roles of vitamin E (tocopherols and tocotrienols) are still not fully clarified. In the last few decades, the enzymatic metabolism of this vitamin has represented a stimulating subject of research. Its elucidation has opened up new horizons to the interpretation of the biological function of that class of molecules. The identification of specific properties for some of the physiological metabolites and the definition of advanced analytical techniques to assess the human metabolome of this vitamin in vivo, have paved the way to a series of hypotheses on the functional implications that this metabolism may have far beyond its catabolic role. The present review collects the available information on the most relevant analytical strategies employed to assess the status and metabolism of vitamin E in humans as well as in other model systems. A particular focus is dedicated to the analytical methods used to measure vitamin E metabolites, and particularly long-chain metabolites, in biological fluids and tissues. Preliminary information on a new LC-APCI-MS/MS method to measure these metabolites in human serum is reported. (C) 2016 Elsevier B.V. All rights reserved
A 17th century Italian treatise on miniature painting and its author(s)
No full textNo abstract available
Regulation of non-antioxidative and inflammatory pathways in macrophages by long-chain metabolites of α-tocopherol
No full textVitamin E wurde erstmals in den 1950er Jahren in der Prävention von kardiovaskulären Erkrankungen (CVD) beschrieben. Durch positive Befunde zahl¬reicher in vitro und im Tiermodell durchgeführter Studien bestand die Hoffnung mit Vitamin E die Entstehung bzw. den Krankheitsverlauf CVD zu beeinflussen. Durchgeführte Humanstudien zeigten jedoch keinen eindeutig positiven Effekt auf die Prävalenz koronarer Herzerkrankungen. Die teils kontroversen Ergebnisse der Human¬studien begründen sich möglicherweise im individuell sehr unterschiedlichen Metabolismus von Vitamin E. Vitamin E ist ein Strukturgemisch aus Isomeren der Tocopherole und Tocotrienole, die sich durch ihr Methylierungsmuster am Chromanolring sowie der Sättigung der Seitenkette unterscheiden. Beim Abbau von Vitamin E in der Leber entstehen langkettigen Metabolite (LCM), α-13‘-OH und α-13‘-COOH, deren physio¬logische und mögliche pathophysiologische Effekte weitgehend unbekannt sind. Wir konnten α 13‘ COOH im Humanserum identifizieren, was erste Hinweise auf seine mögliche physiologische Relevanz gibt. Die LCM sind bezogen auf den Lipidstoffwechsel und ihre anti¬inflammatorische Wirkung, biologisch deutlich aktiver als der metabolische Ausgangsstoff α-TOH. Für das Aufrechterhalten der Lipidhomöostase sind der scavenger-Rezeptor CD36 und die Phagozytose essentiell. Die LCM induzieren signifikant die Expression von CD36 und inhibieren die Phagozytose, konträr zu α-TOH. Die Aufnahme von oxLDL sowie die Akkumulation von Neutrallipiden werden vergleichbar zu α-TOH und seinen LCM gesenkt. Weiterhin wird die Stimulation inflammatorischer Marker, konträr zu α-TOH durch α 13‘-COOH signifikant gehemmt, ebenso wie die sich anschließende Produktion von Signalmoleküle. Weitere Ergebnisse deuten darauf hin, dass die α LCM selbst eine neue Klasse von regulatorischen Signal¬molekülen darstellen. Diese Ergebnisse könnten einen entscheidenden Beitrag zur weiter¬führenden Aufklärung der biologischen Funktion von Vitamin E erzielen
A 17th century Italian treatise on miniature painting and its author(s)
No full textNo abstract available
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