[Reduction of dehydroascorbic acid by thiols in presence of biocatalytic substances: polarographic study].

The chemical reduction of dehydroascorbic acid is studied in the presence of organic and vitaminic compounds. Redox properties of the compounds: ascorbic acid, dehydroascorbic acid, thiols such as glutathion, cistein, British anti-Lewisite (BAL), thiamin, riboflavin, para amino benzoic acid, biotin, 1-4 dihydronaphtoquinone and flavonoids (flavone and derived salts, quercetin rutin, 1-epicatechin and dimer) are established by direct and pulse polarography. The redox reactions are analysed by amperometry. From the results, it appears that the catalytic effect of biocatalyst of the dehydroascorbic reduction by thiols has no direct relation with the redox properties. This catalytic effect is specifically obtained with flavan-3 ol complex with antiscorbutic activities of C2 factor type.