Effects of linoleic acid position in phosphatidylcholines and cholesterol addition on their rates of peroxidation in unilamellar liposomes.
Unilamellar liposomes of phosphatidylcholines (PCs), 1-palmitoyl-2-linoleoyl-3-sn-PC (PLPC), 1-linoleoyl-2-palmitoyl-3-sn-PC (LPPC), and a 1:1 mixture of 1,2-dilinoleoyl-3-sn-PC and 1,2-dipalmitoyl-3-sn-PC (DLPC/DPPC), were peroxidized by the addition of a water-soluble 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and of a lipid-soluble 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (MeOAMVN). LPPC liposomes showed the lowest oxidizability and kinetic chain-length values on AAPH-initiated peroxidation. On MeOAMVN-initiated peroxidation, PLPC liposomes with their lower peroxidation kinetic values were more stable than LPPC or DLPC/DPPC liposomes. The incorporation of cholesterol into the liposomes induced dose-dependent inhibition of PLPC and of LPPC peroxidation, while its effect was less important for the DLPC/DPPC liposomes. Our results indicate that the sn-position of unsaturated acyl chains and the cholesterol content are important modulating factors in the oxidizability of membrane phospholipids.
Mazari
Azzedine
A
The United Graduate School of Agricultural Science, Gifu University, Gifu, Japan.
Iwamoto
Satoshi
S
Yamauchi
Ryo
R
D002784:Cholesterol / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008041:Linoleic Acids; D015227:Lipid Peroxidation; D010713:Phosphatidylcholines / Q000737:chemistry* / Q000378:metabolism*; D012996:Solutions; D053835:Unilamellar Liposomes / Q000378:metabolism*
D008041:Linoleic Acids; D010713:Phosphatidylcholines; D012996:Solutions; D053835:Unilamellar Liposomes; D002784:Cholesterol