Various statements made by chemists relating to vitamin C have briefly been mentioned in order to show how the author developed its research commenced early in Feb. 1934.
Ascorbic acid has been isolated in crystalline form not only from sup-rarenal cortex of oxen, but also from Daikon juice (Daikon,
Rhapanus Sativus. L.), Natumikan juice (a kind of Japanese lemon,
Citrus Aurantium, L.
var. sinensis, Engl.) and Japanese green tea. By its elementary analytical values, specific rotation and other chemical and physical properties, this ascorbic acid has been proved to be identical with the existing acid.
Two therapeutic experiments were carried out with positive results paral-lel to each other, to examine the first two ascorbic acid preparations, namely, preparation obtained from suprarenal cortex of oxen and that from Daikon juice, for antiscorbutic activity on scurvy in guinea pigs, and the results show, so far as these preparations are concerned, that this ascorbic acid was effec-tive in a daily dose of 0.8mg.
Another therapeutic experiment using an ascorbic acid preparation obtained from Japanese green tea, is now in progress. So far this preparation seems to be effective also.
These evidences seem to support Szent-Györgyi's theory that vitamin C and ascorbic acid are identical.
A slight but favourable modification has been made on the method of Szent-Györgyi for obtaining ascorbic acid from suprarenal cortex.
A full description of procedure for isolating ascorbic acid is given in the case of suprarenal cortex and of Daikon juice.
In connection with the case of Natumikan juice or Japanese green tea, where isolation procedure was substantially the same as that in the other cases, are given some notes necessary for isolating ascorbic acid.
Dichlorphenol-indophenol-a reagent proposed by Tillmans as one capa-ble of determining vitamin C in foods-has been applied in the case of sup-rarenal cortex and of the other vegetables in question, and, in fact, turned out to play such a rôle.
This fact confirms Tillmans' view that the vitamin C and reducing factor in vegetables are always parallel.
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