Browsing by Person "Hammann, Simon"

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Enzymatically formed fatty acid hydroperoxides determined through GC‐MS analysis of enantiomeric excess of hydroxy fatty acids after reduction and ibuprofen derivatization
(2025) Hotz, Lisa; Zartmann, Anne; Noack, Isabelle; Drees, Luca J.; Kuschow, Meret K.; Heinrich, Markus R.; Janssen, Hans‐Gerd; Hammann, Simon
Unsaturated fatty acids are susceptible to lipid oxidation through autoxidation, photooxygenation or enzymatical oxidation. A characteristic feature of enzyme‐catalyzed oxidation is the high regio‐ and stereospecificity of the formed fatty acid hydroperoxides. In this study, we present a method to quantify enzymatic lipid oxidation through reducing hydroperoxy fatty acid methyl esters to hydroxy fatty acid methyl esters and derivatizing them with enantiopure (S)‐ibuprofen, allowing the resolution of the enantiomer pairs as diastereomers via achiral GC‐MS. After application to enantiopure reference fatty acids, the approach was applied to autoxidation products of linoleic acid, and the expected racemic mixtures of the 9‐ and 13‐hydroperoxide derived hydroxy fatty acids were detected. On the other hand, when linoleic acid was oxidized using soybean lipoxygenase, clear enantiomeric excess of the (13S) enantiomer could be detected, proving the applicability of this method to detect enzymatic oxidation through enantiomeric excess.
New fluorogenic triacylglycerols as sensors for dynamic measurement of lipid oxidation
(2025) Handke, Maria; Beierlein, Frank; Imhof, Petra; Schiedel, Matthias; Hammann, Simon
Lipids are major constituents of food but are also highly relevant substructures of drugs and are increasingly applied for the development of lipid-based drug delivery systems. Lipids are prone to oxidative degradation, thus affecting the quality of food or medicines. Therefore, analytical methods or tools that enable the degree of lipid oxidation to be assessed are of utmost importance to guarantee food and drug safety. Herein, we report the design, synthesis and application of the first-in-class fluorogenic triacylglycerols that enable dynamic monitoring of lipid oxidation via straightforward fluorescence readout. Our fluorogenic triacylglycerols can be used in both aqueous and lipid-based environments. Furthermore, we showed that the sensitivity of our fluorescent tracers towards oxidation could be tuned by incorporating either saturated or unsaturated acyl chains in their triacylglycerol core structure. With this, we provide a first proof of principle for the applicability of fluorescently labelled triacylglycerols as tracers to monitor the dynamics of lipid oxidation, thus paving the way for novel discoveries in the area of lipid analytics.