Premium
Raman and Fourier transform infrared study of phytol effects on saturated and unsaturated lipid multibilayers
Author(s) -
Picquart M.,
Lefèvre T.
Publication year - 2003
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.927
Subject(s) - phytol , chemistry , raman spectroscopy , membrane , liposome , phospholipid , infrared spectroscopy , organic chemistry , crystallography , analytical chemistry (journal) , biochemistry , physics , optics
The effects of phytol on DPPC and OPPC multilayers were investigated using FT‐IR and Raman spectroscopy. The results were compared with those obtained with α‐tocopherol (α‐T) and α‐tocopherol acetate (α‐TA). The chain packing was analyzed using Raman intensity ratios measured in the CH 2 stretching region, whereas the number of gauche bonds introduced by phytol was estimated by the measure of the FT‐IR absorbance of the CH 2 wagging progression modes. It is shown that the chain packing is reduced and that gauche rotamer formation is promoted by phytol in the gel phase. Phytol has a very similar effect on the acyl chains of DPPC to α‐T but does not have the same impact on the CO stretching vibrations of this lipid. The results indicate that phytol perturbs the interfacial region of DPPC causing dehydration or a conformational modification of the ester groups. Furthermore, the modification of the OPPC chain order induced by phytol is slightly different with respect to α‐T. It is concluded that (1) a hydrogen bond between the hydroxyl group of α‐T and the phospholipid carbonyl groups may not necessarily be associated with the stabilization of the membrane, (2) the studied phytyl compounds may be located more or less close to the membrane interface, (3) the presence of the chromanol ring may strongly influence the location of vitamin E within the membrane and, consequently, its capacity to catch free radicals and (4) the hydroxyl group, chroman moiety and phytyl chain all play a crucial role that determines the effects of α‐T on lipid acyl chains and its location within membranes, which in turn can affect its biological function. Copyright © 2002 John Wiley & Sons, Ltd.