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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 23:06 |
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Conference: Bucharest University Faculty of Physics 2003 Meeting
Section: Electricity and Biophysics
Title:
Antioxidant effects on liposomes with chlorophyll a
Authors:
Marcela Barbīnta - Patrascu*, Manuela Voinea**, Laura Tugulea*
Affiliation:
*Faculty of Physics- University of Bucharest
** Institute of Normal and Pathological Cellular Biology "N. Simionescu"
E-mail
Keywords:
Abstract:
Liposomes with chlorophyll a (Chla) are useful model membranes and physical and chemical studies on these models could bring relevant insights for lipid and Chl dynamics within the bilayer. Both lipids and Chla are susceptible for oxidation by different physical or chemical factors. Antioxidant effect of tocopherols was studied by exploiting the spectral properties (absorption and emission in VIS) of Chla.
Unilamellar liposomes were obtained from multilamellar vesicles by mechanical dispersion (Vortex) and bath sonication for 30-40 minutes. Soybean lecithine (17% PC, Sigma) was dissolved in chloroform, together with Chla (Chla/lipid molar ratio of 1/100) and different concentrations of tocopherol. Chla was obtained in the laboratory, from fresh spinach leaves, by the chromatographic method. The multilamellar vesicles were dispersed in buffer solutions at pH 7. The UV and VIS spectra were recorded to observe the Chla and lipid oxidation. The dimension and properties of liposomes were investigated also by electron microscopy using standard negative staining.
Physical properties (size and shape) and the antioxidant effect of tocopherol on liposomes with Chla were monitored by correlating the absorption spectra and electron microscopy data. It was formerly observed a connection between lipid oxidation and photooxidation of Chla. By using spectral criteria the effect of tocopherol as a suitable antioxidant agent was demonstrated.
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