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Electrochemical oxidation of cholesterol: An easy way to generate numerous oxysterols in short reaction times
Author(s) -
Weber Dieter,
Ni Zhixu,
Vetter Daniel,
Hoffmann Ralf,
Fedorova Maria
Publication year - 2016
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.201500101
Subject(s) - oxysterol , chemistry , in vivo , amperometry , cholesterol , electrochemistry , enzyme , redox , biochemistry , combinatorial chemistry , organic chemistry , biology , electrode , microbiology and biotechnology
Oxysterol species are formed in vivo by enzymatic and non‐enzymatic oxidation of cholesterol. Oxysterols were shown not only to be intermediates in the biosynthesis of bile acids and steroid hormones but also to possess versatile bioactivities. Many functions of oxysterols are not fully understood, others may not have been discovered yet, especially those of non‐enzymatic origin. The limited accessibility to standard compounds challenges both analytics and functional studies. Here an amperometric flow‐through electrochemical (EC) oxidation of cholesterol was applied to generate numerous oxidation products within short reaction times. Besides nine oxysterols confirmed with standard compounds (LC‐MS), more than 10 additional, not identified oxidation products were present. The oxidation sites of the identified compounds were in agreement to the expected accessibility of the cholesterol backbone to free radical driven oxidation. Additionally, the presence of three products which are known to be synthesized enzymatically in vivo demonstrated a successful mimicking of these processes by EC as well. Several of the unidentified species showed the same analytical behavior (retention time and MS/MS) as compounds observed in extracts from a cardiomyocyte cell model of nitrosative stress. Further investigation of electrochemically generated compounds will allow identification and characterization of new oxysterols in vivo. Practical applications: Electrochemical oxidation of cholesterol generates numerous oxysterols in short reaction times. The identified products were oxysterols known to be generated in vivo by both free radical and enzymatic processes. Among the unidentified oxidation products were species which showed the same analytical behavior as substances in extracts from stressed cell cultures. Further investigation of EC‐generated compounds may facilitate identification and characterization of new in vivo relevant oxysterols and the synthesis of standards for biological and analytical applications. Electrochemical oxidation of cholesterol generates numerous oxysterols in short reaction times. The nine identified products were oxysterols known to be generated in vivo by both free radical and enzymatic processes. Among the 15 unidentified oxidation products were species which showed the same analytical behavior as substances in extracts from stressed cell‐cultures, indicating biological significance of the new electrochemically generated oxysterols.