Abstract
In view of the fact that a portion of the Vitamin C intake of animals and man may be in the form of dehydroascorbic acid, 1-4 it is of interest to know whether the unstable reversibly oxidized form can be utilized efficiently, and whether there is a significant degree of reduction to ascorbic acid in the intestinal tract. It is clearly recognized that dehydroascorbic acid is effective as an antiscorbutic agent, 5-8 but there has been wide variation in the results from different laboratories regarding (a) the protective dosage required and (b) the relative utilization when administered by ingestion and injection.
The tendency toward irreversible decomposition of dehydroascorbic acid 9-10 is such that utilization from the intestinal tract would be greatly influenced by (a) the low pH range of the stomach contents, (b) a rapid reduction to ascorbic acid by the contents of the intestinal tract, and (c) the rate of assimilation from the intestinal tract, followed by, or coincident with, reduction to the stable form. Biological assays carried out in our own laboratory 11 indicate that dehydroascorbic acid is nearly as effective antiscorbutically as ascorbic acid when administered with sufficient care, either orally or parenterally. The time factor in manipulating the reagents, pH of reagents, and the condition of the animals no doubt all have an important bearing upon the results of such assays.
In a previous communication 12 the reduction of dehydroascorbic acid by guinea pig tissues was studied in detail, with the conclusion that diffusible and fixed sulfhydryl compounds were responsible for nearly all of the reducing action, without the interposition of enzymic activity. The products of protein digestion have also been shown to exert a protective action toward the reduced form of the vitamin. 13
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