Is measuring OH^. radical scavenging a reasonable measurement of antioxidant properties?

The measurement of the hydroxyl radical scavenging properties of a compound is not indicative on its antioxidant properties in vivo. To get such information one has to elucidate the mechanism of its reaction with typical secondary radicals, mainly typical RO₂^. radicals and to some degree with R^. radicals. Elucidation of the mechanisms of reaction is essential before a conclusion regarding the antioxidant properties can be derived. One should remember that in vivo even vitamins C and E might act as pro-oxidants.