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Effect of cholesterol on distribution of stable, hydrophobic perchlorotriphenylmethyl triethylester radical incorporated in lecithin liposomal membranes.
- Source :
-
Chemical & pharmaceutical bulletin [Chem Pharm Bull (Tokyo)] 2011; Vol. 59 (5), pp. 624-8. - Publication Year :
- 2011
-
Abstract
- Perchlorotriphenylmethyl triethylester radical (PTM-TE) is a hydrophobic, stable radical giving a narrow singlet ESR signal with a small satellite signal for (13)C in organic solvents. In order to use PTM-TE as a label of liposomal membranes, its manner of incorporation into liposomal membranes was studied. Two components, broad and narrow signals, were observed on the ESR spectrum of PTM-TE incorporated into liposomal membranes composed of egg yolk phosphatidylcholine (egg-PC). The broad signal was increased by the presence of cholesterol in the membranes. The spectral anisotropy of the broad signal was very small as analyzed with oriented planar multilamellar membranes. The narrow signal increased with an increase in temperature in the absence of cholesterol, whereas only a small increase in the signal was observed in the presence of cholesterol. The g-value and line width of the narrow signal were very close to those of PTM-TE in mineral oil, whose viscosity is close to the microviscosity in the hydrophobic region of egg-PC membranes. On the other hand, the g-value and line width of the broad signal were close to those of solid PTM-TE. These observations indicate that the broad signal observed in liposomes originates from PTM-TE clusters in the membranes. The clusters were dissolved in egg-PC membranes at a PTM-TE/egg-PC molar ratio of less than 0.017. However, the clusters were hardly dissolved in the presence of cholesterol.
- Subjects :
- Carbon Radioisotopes chemistry
Cholesterol chemistry
Egg Yolk chemistry
Egg Yolk metabolism
Electron Spin Resonance Spectroscopy methods
Esters chemistry
Free Radicals chemistry
Hydrophobic and Hydrophilic Interactions
Perchlorates chemistry
Trityl Compounds chemistry
Cholesterol pharmacology
Drug Delivery Systems methods
Hydrocarbons, Chlorinated chemistry
Lecithins metabolism
Liposomes metabolism
Membranes, Artificial
Subjects
Details
- Language :
- English
- ISSN :
- 1347-5223
- Volume :
- 59
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Chemical & pharmaceutical bulletin
- Publication Type :
- Academic Journal
- Accession number :
- 21532201
- Full Text :
- https://doi.org/10.1248/cpb.59.624