Vitamin E models. Can the anti-oxidant and pro-oxidant dichotomy of α-tocopherol be related to ionic ring closing and radical ring opening redox reactions?

The free radical scavenging mechanism, leading to a quinodal structure via an oxidative ring opening is exothermic. However, the ionic oxidative ring opening is endothermic. Consequently, the ionic reductive ring closing must be exothermic. This leads to the suggestion that Vitamin E may be recovered, unchanged, thus effectively acts as a catalyst for the following reaction2HOO+H3O(+)+NADH→2HOOH+H2O+NAD(+),ΔE≈−120kcalmol−1.As Vitamin E is …