Antioxidant-prooxidant inversion

Scheme 5.4 Iron dithiocarbamate (FeDRC) antioxidant-prooxidant inversion in a polyolefin (P represents a polyolefin chain)...

Free radicals are highly reactive molecules that have been implicated in cardiovascular and neurodegenerative disease. Hunt et al. generated superoxide radicals in both cell-free and human placental tissue to determine if St. John s wort has antioxidant qualities. They then tested St. John s wort samples that were standardized to either hypericin or hyperforin. In cell-free studies, both samples had a prooxidant effect at a 1 1 concentration. Both showed an inverse dose-related relationship in their antioxidant effect at concentrations from 1 2.5 to 1 20, with 1 20 having the greatest antioxidant effect in both groups. St. John s wort standardized to hypericin was superior in its antioxidant properties compared with hyperforin. Both were shown to be significant... 

Some thiolate metal complexes, unlike the oxygen complexes referred to above are powerful antioxidants (see Chapter 1) and undergo inversion to prooxidant metal ions in sunlight. The iron, manganese, cobalt, vanadium and cerium dithiocarbamates (II) are typical examples of such restrained prooxidants. 

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