Ascorbic Acid from Iris and Other Plants by a Simplified Method. ∗

Abstract

We have had great difficulty in obtaining more than a few milligrams of the antiscorbutic vitamin, ascorbic acid, from either plant sources or suprarenal glands by the published methods of Szent-Györgyi 1 or of Waugh and King 2 and Svirbely and King. 3 Large and uncontrolled losses occur at many places in both processes as published. Svirbely and Szent-Györgyi 4 have just reported a somewhat modified procedure, using the Hungarian sweet pepper from which paprika is made, which contains considerably more vitamin C than we have obtained from the American sweet pepper—another variety of Capsicum annuum. We have studied the causes of these losses with a view to developing a more certain method of preparation. A survey of common plants was also made to find richer sources of the vitamin. Some of these results have been published by Marine, Baumann and Webster. 5 Leaves of German iris (Iris germanica) are by far the most satisfactory material from which to extract vitamin C, both because the vitamin is present in high concentration and because there are fewer substances in this plant that interfere with its separation. Most plants have a relatively high concentration of ascorbic acid in the young actively growing portions but on maturation, the vitamin rapidly disappears. In German iris leaves, however, the concentration of the vitamin, which is 600 mg. per 100 gm. of fresh leaf in early spring, remains as high as 250 or 300 mg. per 100 gm. in late summer, and this plant offers a very rich source during the entire growing season. Skunk cabbage (Symplocarpus foetidus) gathered during April and May and sweet green peppers as purchased from January to May both contained between 100 and 200 mg. per 100 gm.