Reaction products of gamma-tocopherol with (E)-4-oxo-2-nonenal in acidic acetonitrile.

gamma-Tocopherol was reacted with (E)-4-oxo-2-nonenal (ONE) at 37 degrees C in an acidic acetonitrile solution. The reaction products were isolated by reversed-phase high-performance liquid chromatography and their structures were characterized to be 5-substituted gamma-tocopherols: 5-(1-(furan-2-yl)pentyl)-gamma-tocopherol (1), 3-(1-butyl-4,5,7-trimethyl-7-(4,8,12-trimethyltridecyl)-8,9-dihydro-7H-furo[3,2-f]chromen-2yl)propanal (2), and 1-(1-butyl-4,5,7-trimethyl-7-(4,8,12-trimethyltridecyl)-8,9-dihydro-7H-furo[3,2-f]chromen-2-yl)-4-(furan-2-yl)octan-3-one (3). Compound 1 was the predominant product under the mild acidic conditions, whereas compounds 2 and 3 were relatively stable and accumulated during the reaction. Compound 1 was detected as the product when gamma-tocopherol and ONE were incubated in methyl linoleate in the presence of dicetyl phosphate. The results indicate that gamma-tocopherol may trap ONE under acidic conditions of lipid peroxidation.