Cholesterol Epoxidations by Defined Oxygen Species
Part of the
Basic Life Sciences
book series (BLSC, volume 49)
Each defined species of active oxygen implicated in oxygen biochemistry, with the exception of superoxide (· O2 -, HOO ·), is known to oxidize cholesterol under conditions potentially present in vivo. Oxysterols found in tissues thus may have at least two origins, enzymic ones related to in vivo metabolism (including lipid peroxidation) and nonenzymic origins in which active oxygen species hydroxyl radical (HO), dioxygen cation (O2 +) singlet dioxygen (1O2), ground state dioxygen (3O2), peroxide (O2 2-, HOO-, H2O2) ozone (O3), and as yet unrecognized species may be implicated. As the oxysterols formed in all cases have demonstrated biological activities in a variety of bioassays, the question must be posed whether such oxysterols, if formed in. vivo and not properly controlled by protective metabolism, are a threat to human health.
KeywordsSteryl Ester Cumene Hydroperoxide Carbonyl Oxide Cholesterol Oxide Carbon Nuclear Magnetic Resonance
J. Gumulka, J. S. Pyrek, and L. L. Smith, Interception of discrete species of oxygen in aqueous media by cholesterol: Formation of cholesterol epoxides and secosterols, Lipids
17:197 (1982).CrossRefGoogle Scholar
J. Gumulka and L. L. Smith, Ozonization of cholesterol, J. Am. Chem. Soc.
105:1972 (1983).CrossRefGoogle Scholar
K. Tori, T. Komeno, and T. Nakagawa, Nuclear magnetic resonance studies on steroids.111. Steroidal epoxides and episulfides, J. Org. Chem.
29:1136 (1964).CrossRefGoogle Scholar
B. O. Lindgren and C. M. Svahn, Epoxides formed by chlorination of cholesterol and cholest-4-en-3ß, 63-diol, Acta Chem. Scand.
24:2699 (1970).CrossRefGoogle Scholar
G. Assmann, D. S. Fredrickson, H. R. Sloan, H. M. Fales and R. J. Highet, Accumulation of oxygenated steryl esters in Wollman’s disease, J. Lipid Res.
16:28 (1975).PubMedGoogle Scholar
G. A. S. Ansari and L. L. Smith, The oxidation of cholesterol by hydroxyl radical, Photochem. Photobiol.
30:14 7 (1979).CrossRefGoogle Scholar
L. S. Tsai and C. A. Hudson, Cholesterol oxides in commerical dry egg products: Isolation and identification, J. Food Sci.
49:1245 (1984).CrossRefGoogle Scholar
© Plenum Press, New York 1988