Abstract:
Since its discovery nearly a century ago, a-tocopherol (vitamin E) research has
been mainly focused on its ability to terminate the cycle of lipid peroxidation in
membranes. Nitrobenzoxadiazole fluorescent analogues were made previously to study
the intracellular transfer of vitamin E in cells. However, these molecules were reportedly
susceptible to photobleaching while under illumination for transfer assays and
microscopy.
Here is reported the synthesis of a series of fluorescent analogues of vitamin E
incorporating the more robust dipyrrometheneboron difluoride fluorophore (BDP-a-Tocs;
Aex = 507 nm, Aem = 511 nm). C8-BDP-a-Toc 42c, having an eight-carbon chain between
the chromanol and fluorophore, wa<; shown to bind specifically to a-tocopherol transfer
protein with a dissociation constant of approximately 100 nM. Another fluorescent
analogue of vitamin E with a thienyl derivative of BODIPY that is excited and fluoresces
at longer wavelengths (Aex = 561 nm, Aem = 570 nm) is in development.
