I.       ROO·   +   a-TOH                           ROOH   +    a-TO·

 

II.     a-TO·   +  CoQ10H2                             a-TOH  + CoQH·

                               

                           second electron

         CoQH·                                        CoQ

 

III.     ROO·  +  a-TO·                                nonradical products

 

IV.      a-TO·   +   RH (PUFA)                         a-TOH   +    R· (Alkyl radical) 

 

 

         R·   +  O2                             ROO· (peroxyl radical of PUFA)

ROOH = Polyunsaturated fatty acid (PUFA) hydroperoxide. ROO· = Peroxyl radical of PUFA. a-TOH = Vitamin E, a-Tocopherol. a-TO· = Tocopheryl radical.

CoQ10H2 = Ubiquinol. CoQH· = ubisemiquinone. CoQ = ubiquinone. R· = Alkyl radical.

 

Fig. (8). The mechanism of vitamin E (a-TOH)-mediated LDL lipid peroxidation.