The Antioxidant Vitamin E as a Membrane Raft Modulator: Tocopherols do not Abolish Lipid Domains
Mitchell DiPasquale, Michael H. Nguyen, Brett W. Rickeard, Nicole Cesca, Christopher Tannous, Stuart R. Castillo, John Katsaras, Elizabeth Kelley, Frederick A. Heberle, Drew Marquardt
A great deal of individuals across North America regularly supplement their diet with the antioxidant, vitamin E. This billion-dollar supplementation industry encourages the use of vitamin E with little evidence supporting its actual health benefits. Moreover, based on few endorsing clinical studies, many supplement vitamin E as a lipid raft destabilizing anti-cancer agent, in conjunction to its antioxidant behaviour. Here, we investigate the influence of vitamin E on membrane raft stability to interrogate if supplementation is truly predicated on molecular evidence. We probe phase-separating compositions of unilamellar vesicles with small angle scattering techniques and fluorescence microscopy to evaluate lipid domain stability in the presence of various tocopherol analogues. Our study suggests that phase behaviour remains unperturbed well beyond physiological concentrations of vitamin E (up to 10 mol%). These results are reminiscent of studies proposing a "line active" role of vitamin E at the domain boundary, and additionally, they indicate that this property alone does not discriminate the various species. We discuss the implications of these findings as they pertain to lipid raft modification in the native membrane, and propose a new dimension to the antioxidant mechanism of vitamin E.
Biochimica Et Biophysica Acta-Biomembranes
vitamin E, tocopherol, lipid membrane, raft, small angle scattering
, Nguyen, M.
, Rickeard, B.
, Cesca, N.
, Tannous, C.
, Castillo, S.
, Katsaras, J.
, Kelley, E.
, Heberle, F.
and Marquardt, D.
The Antioxidant Vitamin E as a Membrane Raft Modulator: Tocopherols do not Abolish Lipid Domains, Biochimica Et Biophysica Acta-Biomembranes
(Accessed February 27, 2024)