Interconversion of α-tocopherol and its oxidation products

摘要: Abstract α-Tocopheroxide is not readily reduced polarographically and in mixtures with α-tocopherol does give a stable electromotive potential; thus α-tocopheroxide the electromotively active, bivalent oxidation product detectable polarographically. Various experiments are reported on conversion of to α-tocopherylquinone; under weakly acidic conditions forms α-tocopherylquinone, whereas similar ascorbic acid present formed. The formation common intermediate hemi-ketal structure both reactions considered as likely possibility. No was detected spectrophotometrically during slow α-tocopheryl;quinone near neutral pH. Treatment α-tocopherylquinone absolute ethanol hydrochloric acids converts quinone principally α-tocopherol, or closely resembling by pathway involving α-tocopherylhydroquinone; some preparations considerable amounts products unknown Ascorbate act synergistically prevention acceleration cytochrome c linoleate Neither effective without ascorbate. implications these other findings discussed.