24] Inhibition of plasma cholesterol ester hydroperoxide and phosphatidylcholine hydroperoxide formation as measures of antioxidant status

Abstract

Publisher Summary The oxidation of lipids produces lipid hydroperoxides and cyclic peroxides as primary products, as well as secondary products such as alcohols, aldehydes, epoxides, ketones, and carboxylic acids. The products of protein oxidation are less well understood than those of lipids and are only poorly characterized. The formation of hydroperoxides, carbonyl compounds, and disulfide has been observed following protein oxidation. The oxidation of DNA yields both single- and double-strand breakage and numerous oxygenated products of DNA bases. Of these, 8-hydroxyguanine and thymine glycol are well characterized. Analyses of plasma lipid oxidation products have been extensive, and many methods for their quantitation have been devised and applied. The iodometric titration method has been used for quantitative measurement of total peroxide. This method is specific and quantitative, but may not be sensitive enough for biological fluids. The so-called thiobarbituric acid (TBA) test has been employed to a great degree to quantify lipid peroxidation products. Other methods for measuring hydroperoxides have utilized cyclooxygenase, methylene blue derivatives, Fe(III)-xylenol orange, and specific oxidation products such as 4-hydroxynonenal, F 2 -isoprostanes, or oxysterols.