VITAMIN-E ANALOG TROLOX-C - ELECTRON-SPIN-RESONANCE AND PULSE-RADIOLYSIS STUDIES OF FREE-RADICAL REACTIONS

  • 15 October 1988
    • journal article
    • research article
    • Vol. 255  (2) , 513-522
Abstract
The reactions between Trolox C, a water-soluble vitamin E analogue, and several oxidizing free radicals including the hydroxyl radical and various peroxy radicals were examined by using the pulse-radiolysis technique. The results demonstrate that Trolox C may undergo rapid one-electron-transfer reactions as well as hydrogen-transfer processes; the resulting phenoxyl radical is shown to be relatively stable, in common with the phenoxyl radical derived from vitamin E. The reactions between the Trolox C phenoxyl radical and a variety of biologically relevant reducing compounds were examined by using both pulse radiolysis and e.s.r. The results demonstrate that the Trolox C phenoxyl radical is readily repaired by ascrobate (k = 8.3 .times. 106 dm3 .cntdot. mol-1 .cntdot. s-1) and certain thiols (k < 105 dm3 .cntdot. mol-1 .cntdot. s-1) but not by urate, NADH or propyl gallate. Evidence from e.s.r. studies inducates that thiol-containing compounds may also enter into similar repair reactions with the .alpha.-tocopherol phenoxyl radical. Kinetic evidence is presented that suggests that Trolox C may ''repair'' proteins have been oxidized by free radicals.

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