Free radicals from 1-palmitoyl-2-arachidonoylphosphatidylcholine liposomes in Fe2+/ascorbic acid solution.
The generation of free radicals during the lipid peroxidation of liposomes composed of 1-palmitoyl-2-arachidonoylphosphatidylcholine (PAPC-liposome) in Fe2+/ascorbic acid (AsA) solution was studied by the ESR spin trapping technique. A carbon-centered radical adduct was observed using alpha-(4-pyridyl-1-oxide)-N-tert-butyl-nitorone (4-POBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), but no oxygen-centered radicals such as .OH, LO., and LOO. were observed. The lipid peroxidation evaluated as 2-thiobarbituric acid reactive substances was inhibited by the addition of 4-POBN. The intensity of this inhibitory effect was dependent on the time when 4-POBN was added to the mixture of PAPC-liposomes and Fe2+/AsA solution, and no inhibitory effect could be observed after 4 min. The signal intensity of the carbon-centered radical adduct was dependent on the lipid concentration of PAPC-liposomes. These results suggest that the alkyl radicals generated from PAPC-liposome peroxidation induced by Fe2+/AsA were trapped by DMPO or 4-POBN at an earlier stage of lipid peroxidation.
Yoshida
T
T
School of Pharmacy, Tokyo University of Pharmacy and Life Science, Japan.
Otake
H
H
Aramaki
Y
Y
Hara
T
T
Tsuchiya
S
S
Hamada
A
A
Utsumi
H
H
D001205:Ascorbic Acid; D003497:Cyclic N-Oxides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005296:Ferrous Compounds; D005609:Free Radicals / Q000737:chemistry; D007700:Kinetics; D015227:Lipid Peroxidation; D008081:Liposomes / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry; D010742:Phospholipid Ethers / Q000737:chemistry*; D011725:Pyridines; D012996:Solutions; D013113:Spin Labels; D013858:Thiobarbiturates / Q000737:chemistry
D003497:Cyclic N-Oxides; D005296:Ferrous Compounds; D005609:Free Radicals; D008081:Liposomes; D009589:Nitrogen Oxides; D010742:Phospholipid Ethers; D011725:Pyridines; D012996:Solutions; D013113:Spin Labels; D013858:Thiobarbiturates; C043438:alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; C043051:1-O-hexadecyl-2-arachidonyl-sn-glycero-3-phosphocholine; C017245:5,5-dimethyl-1-pyrroline-1-oxide; C029684:thiobarbituric acid; D001205:Ascorbic Acid