Cholest-3,5-dien-7-one formation in peroxidized human plasma as an indicator of lipoprotein cholesterol peroxidation potential

• Published in: Biochimica et biophysica acta 1995-04, Vol.1255 (3), p.341-343
• Main Authors: Hahn, Mikyoung, Tang, Maoyun, Subbiah, M.T.Ravi
• Format: Article
• Language: English
• Subjects: Cholest-3,5 dien-7-one; Cholestenones - blood; Cholestenones - metabolism; Cholesterol - metabolism; Cholesterol peroxidation; Chromatography, Gas; Digitonin precipitation; Humans; Lipid Peroxidation; Lipoprotein; Lipoproteins - metabolism; Spectrophotometry, Ultraviolet
• ISSN: 0005-2760; 0006-3002; 1879-145X
• DOI: 10.1016/0005-2760(95)00004-V

Lipoprotein peroxidation susceptibility is routinely evaluated using products of unsaturated fatty acids as markers (e.g., malonaldehyde). The significance and factors influencing peroxidation of cholesterol moiety of lipoproteins are relatively unknown due to lack of a reliable marker product which can be measured easily. Under the influence of Cu 2+ ions, the major product of lipoprotein cholesterol peroxidation (isolated after saponification) was cholest-3-5-dien-7-one (CSD). Apart from gas-liquid chromatography, this compound lends itself for measurement by alternative methods. Due to lack of the 3β-hydroxyl group, CSD was separated from the rest of the oxysterols and cholesterol by passing through digitonin-coated silica-gel G and its concentration was determined by absorption at 283 nm. The recovery of CSD by this method exceeded by 87%. The formation of CSD was also sensitive to vitamin E and therefore could be used as an index of lipoprotein cholesterol susceptibility to peroxidation.