Oxyradical scavenging effects of dehydroascorbate

Abstract

Dehydroascorbate (DHA) has been shown to possess vitamin C like activities as well as to protect the lens against oxidative stress and cataract formation. The results presented here suggest that some of the beneficial effects of DHA can be attributed to its property of undergoing peroxidative decarboxylation and of $O_2^{\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{ - } }$ scavenging. Incubation of 1-¹⁴C-DHA with peroxide at physiological pH has been found to liberate ¹⁴CO₂ in quantitative yields, with recovery of 79–94%. The recovery increases with the increase in the amount of DHA used. Its $O_2^{\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{ - } }$ scavenging activity was apparent by inhibition of $O_2^{\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{ - } }$ dependent reduction of ferricytochrome c and nitroblue tetrazolium. The authenticity of the latter mechanism was proved by inhibition of the $O_2^{ \cdot - }$ dependent reactions also by superoxide dismutase.