European Journal of Lipid Science and Technology

Routes of production and structures of some of the major side-chain oxysterols. (A) Side-chain oxysterols enzymatically derived from cholesterol include 24S-, 25-, and 27-hydroxycholesterol. (B) The shunt pathway runs parallel to cholesterol synthesis and leads to the production of 24S,25-epoxycholesterol. Partial inhibition of oxidosqualene cyclase diverts more flux into the shunt pathway, favouring production of this oxysterol.

A schematic representation of the different functions of ACAT1 and ACAT2 in lipoprotein metabolism in humans. ACAT1 synthesizes CEs in different cell types (i.e., macrophages and Kupffer cells) to maintain constant UEC levels. ACAT2 synthesizes CE in enterocytes and hepatocytes fated to storage or to secretion into chylomicrons and VLDL, respectively. Thus, ACAT2 is a relevant determinant of the atherogenic CE transported into remnants. Blue arrows depict fluxes of CE, red arrows depict fluxes of UEC.

Biological functions of ORPs. An ORP at a membrane contact site is depicted.

The mechanism of formation of B-ring COPs by photosensitized oxidation and autoxidation.

Structures of common ASG and SG: (1) spinasteryl glucoside, (2) stigmasteryl glucoside, and (3) sitosteryl palmitoyl glucoside.

Transesterification reaction of tributyrin with phytosterols. Open circles = tributyrin, squares = phytosterols, open triangles = phytosteryl ester, solid circles = dibutyrin, solid triangles = monobutyrin.

The separation of oligomers and monomers by SEC-RI. (a) Cholesteryl stearate, (b) cholesteryl oleate, (c) cholesteryl linoleate, and (d) free cholesterol oxidized at 100°C for 0-5 days.

Fragment ions used for quantification of the target compounds.

GC-MS chromatogram showing resolution of some common cholesterol oxidation products present in a pickled mackerel sample. Peak identification: 1, IS (internal standard); 2, 7α-HC (7α-hydroxycholesterol); 3, Cholesterol; 4, 7β-HC (7β-hydroxycholesterol); 5, β-CE (β-epoxycholesterol-); 6, α-CE (α-epoxycholesterol); 7, CT (cholesteroltriol); 8 25-HC (25-hydroxycholesterol); 9, 7-KC (7-ketocholesterol).