| Abstract
| - Antioxidant interactions between flavonoids and α-tocopherol have been demonstrated by oximetry(oxygen concentration measured by ESR signal line width). In tert-butyl alcohol, a solvent in whichflavonoids are weak retarders of peroxidation of methyl linoleate when initiated by α,α‘-azoisobutyronitrile, quercetin and (−)-epicatechin were found to act synergistically with the chain-breakingantioxidant α-tocopherol. In chlorobenzene, a solvent in which flavonoids are chain-breakingantioxidants, quercetin and (+)-catechin each regenerated α-tocopherol, resulting in a co-antioxidanteffect. The stoichiometric factor of the flavonoids as chain-breaking antioxidants in 1:1 mixtures withα-tocopherol was measured to be close to 1 for quercetin and slightly smaller for the catechins. Theapparent inhibition rate constant, kinh, for the mixture quercetin/α-tocopherol was measured to be 4.1× 105 and 2.6 × 106 M-1 s-1 in tert-butyl alcohol and chlorobenzene, respectively, at 50 °C. A kinh of4.4 × 105 M-1 s-1 was measured for (+)-catechin alone in chlorobenzene at 50 °C. Keywords: Quercetin; (−)-epicatechin; (+)-catechin; α-tocopherol; regeneration; synergism; antioxidants; solvent effect
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