Accurate bond dissociation enthalpies of popular antioxidants predicted by the ONIOM-G3B3 method

Radical-scavenging antioxidants play vital roles in the prevention of oxidative damage caused by free radicals, which is involved in many important chemical and biological processes. Using the ONIOM-G3B3 method, the bond dissociation enthalpies (BDEs) of coenzyme Q, flavonoids, olives, curcumins, indolinonic hydroxylamines, phenothiazines, edaravones and antioxidants used as food additives are predicted in the present study. On the basis of the computed BDE values, discussions were then made about their antioxidant activities, structure-activity relationships, and radical scavenging mechanisms. This work may be useful to clarify the radical scavenging mechanism of antioxidants and to design novel antioxidants.