Abstract
Large unilamellar vesicles (120-160 nm) composed of egg phosphatidylcholine (egg PC) containing approximately 22 wt% of polyunsaturated fatty acids (PUFA) and various mol% (0, 10, 22, or 45) of cholesterol were exposed to oxidative stress. The hydrophilic azo compound 2,2'-azobis-(2-amidinopropane)2HCl (AAPH) which was thermally decomposed to produce a constant flux of peroxy radicals was the source of the oxidative stress (≤ 48 h incubation at 37°C). Cholesterol loss following the oxidation was up to 33%, while PUFA were more extensively damaged; loss was up to 52, 88, and 100% for C-18:2, C-20:4, and C-22:6, respectively. (ii) Oxidizability of cholesterol when quantified in absolute amount was three-fold higher when its level was 45 mol%. The interrelationship between bilayer structure, especially its lateral organization and free volume, and lipid peroxidation are discussed. Differential scanning calorimetry of oxidized multilamellar vesicles lacking cholesterol revealed that a high level of oxidative damage to egg phosphatidylcholine PUFA resulted in the loss of the gel to liquid-crystalline phase transition of egg PC (broad peak at around -8°C).
Original language | American English |
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Pages (from-to) | 17-22 |
Number of pages | 6 |
Journal | Chemistry and Physics of Lipids |
Volume | 87 |
Issue number | 1 |
DOIs | |
State | Published - 1997 |
Bibliographical note
Funding Information:This work was supported in part by The Israel-United States Science Foundation, BSF 95/318 to Y.B.
Keywords
- Acyl chains
- Cholesterol
- Lipid peroxidation
- Liposomes