A new vitamin E (alpha-tocomonoenol) from eggs of the pacific salmon Oncorhynchus keta

A novel alpha-tocomonoenol [3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trime thyl-12-tridecenyl)-2H-1-benzopyran-6-ol] having an unusual methylene unsat uration at the isoprenoid-chain terminus of alpha-tocopherol was isolated f rom the lipophilic fraction of chum salmon eggs. The structure of this mari ne-derived tocopherol (MDT) was established by spectral analyses. The perox yl radical-trapping activities of MDT and alpha-tocopherol were compared in aqueous phosphatidylcholine liposomal suspension and in methanolic solutio n at 37 degrees C. The antioxidant activity of MDT was found to be identica l to that of alpha-tocopherol under the experimental conditions of measurem ent.