Membrane properties of hydroxycholesterols related to the brain cholesterol metabolism

• Malte Hilsch,
• Ivan Haralampiev,
• Peter Müller,
• Daniel Huster and
• Holger A. Scheidt

Beilstein J. Org. Chem. 2017, 13, 720–727, doi:10.3762/bjoc.13.71

• influence on lipid chain order, membrane permeability and formation of lateral domains. Keywords: cholesterol; fluorescence; hydroxycholesterol; membrane structure; NMR; Introduction Cholesterol is a major component of mammalian cell membranes with various biological functions. It plays a key role in

• cholesterol into metabolites, which can easily diffuse into the brain. These metabolites are primarily the oxysterols (24S)-hydroxycholesterol (24S-HC) for the transport from the brain to the bloodstream and 27-hydroxycholesterol (27-HC) for the transport in the opposite direction [4][6][8]. These molecules

• . Furthermore, high exchange rates of the molecules between erythrocytes and plasma were found [7], indicating that 24S-HC and 27-HC can – contrary to cholesterol – rapidly cross plasma membranes. Also for other oxysterols, like 7-ketocholesterol and 25-hydroxycholesterol, a lower tendency to form lateral lipid

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• transformed to 25-hydroxycholesterol (2) in 13% yield (Scheme 1). The statement that the Tl(II)/HMP/O2 adduct, suggested to be a radical in nature, is responsible for cholesterol oxidation was based on the following observations. The electrolysis performed in the divided cell indicated that the oxidation of

• electrochemically generated superoxide radical anion (O2·−) in acetonitrile was described in 1997 [37]. It was established that in dry solution, with water content below 4%, no products were observed. However, cholesterol was oxidized to 7-oxocholesterol (9), 7α-hydroxycholesterol (7), and 7β-hydroxycholesterol (8