Abstract
TAMASAWA, N. and TAKEBE, K. Analytical Examination of Oxidized Free and Esterified 7-Ketocholesterol and Related Oxysterols in Human Plasma Incubated with Copper. Tohoku J. Exp. Med., 1992, 168 (1), 37-45-Oxygenated derivatives of cholesterol (oxysterols) have been demonstrated to possess a wide variety of biological properties and evaluated for their abilities to inhibit cholesterol biosynthesis. We investigated a method to analyze copper-catalyzed oxidation products of human plasma cholesterol. Free and esterified oxysterols produced were mainly 7-ketocholesterol, and small amounts of 7β-hydroxy- cholesterol and 5, 6α-epoxy-cholesterol were also identified. Quantitatively, the sterol nucleus of ester was less susceptible to oxidation than that of the free form. This finding suggested that the cholesterol nucleus of ester form was more resistant against oxidative stress than free form. Additionally we demonstrated that the addition of probucol, a powerful antioxidant used clinically to lower blood cholesterol, inhibited this copper-catalyzed oxdiation of cholesterol.-7- ketocholesterol; free oxysterol; esterified oxysterol; cholesterol oxdiation; probucol
