Cholesterol oxidation products oxysterols detection

Studies conducted by Barenghi eta.1. (1990) and Lodge etal. (1993) independently have demonstrated the facile, multicomponent analysis of a wide range of PUFA-derived peroxidation products (e.g. conjugated dienes, epoxides and oxysterols) in samples of oxidized LDL by high-field H-NMR spectroscopy. Figure 1.9 shows the applications of this technique to the detection of cholesterol oxidation products (7-ketocholesterol and the 5a, 6a and 5/3,60-epoxides) in isolated samples of plasma LDL pretreated with added coppcr(Il) or an admixture of this metal ion with H2O2, an experiment conducted in the authors laboratories. 

Variable amounts of 7a-hydroxycholesterol (10-20 ng/ml), and various oxidized sitosterol forms are found (in ratio of oxidized sitosterol to sitosterol of about 0.04) in soybean oil based lipid emulsions that are frequently used for intravenous feeding. Cholesterol oxides have also been detected at ppm levels in dehydrated foods, potatoes fried in tallow (Chapter 12) and cured animal products. However, there is no adequate evidence of any harmful biological effects on the amounts ingested in a normal diet and on the degree of absorption and metabolism of oxysterols found in foods. One of the most atherogenic oxysterols is 7)5-hydroxycholesterol, but its possible harmful effects in humans are unknown. 

---