The constituents of Gloriosa superba / by Hubert William Bentley Clewer, Stanley Jospeh Green and Frak Tutin.

  • Clewer, Hubert W. B.
Date:
1915.]
Catalogue details

Licence: Public Domain Mark

Credit: The constituents of Gloriosa superba / by Hubert William Bentley Clewer, Stanley Jospeh Green and Frak Tutin. Source: Wellcome Collection.

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    identity of the two preparations, their specific rotatory powers were compared with the following results: 0-1759 * of the base from Gloriosa, made up to 20 c.c. with chloroform, gave aD -2°8/ in a 2-dcm. tube, whence [g]d 5 —121‘3°. 0'1759* of the base from Golchicum, made up to 20 c.c. with chloroform, gave aD 2°7' in a 2-dcm. tube, whence [a]?5 -120-3°. In both these determinations, and also in several others carried out in chloroform solution, it was noticed that the observed rotation dropped from 5—8; during the first thirty minutes after solution, when it remained constant. The rotation of colchicine was also observed to vary very appreciably with the concentration, the specific rotation being less in more concentrated solutions when employing chloroform. A determination in aqueous solution yielded the following results: 03543,* made up to 20 c.c. with water, gave a —15°12/ in a 2-dcm. tube, whence [ajD —429-0°. The colchicine from Gloriosa yielded an aurichloride, which formed soft, yellow needles, and melted at 209° after drying over sulphuric acid : 00800 gave 00214 Au. Au = 267. C22H250,N,HAuC14 requires Au = 267 per cent. The above-recorded analysis of the colchicine seems to indicate that the latter still retained a small amount of water of crystallisa¬ tion after drying in a vacuum, and this is probably the case, since the water which was lost was very rapidly reabsorbed on exposure to the air. On drying colchicine at 105°, however, some slight decomposition appeared to occur. The amount of colchicine isolated in the pure state from Gloriosa was 165 grams, which is equivalent to approximately 004 per cent, of the weight of the drug employed. When, however, the dried and ground Gloriosa tubers were assayed for colchicine by the method described in the United States Pharmacopoeia, the amount of alkaloid found was equivalent to 03 per cent, of the weight of the dried tubers. A portion of the aqueous liquid (A) which had been extracted with ether and amyl alcohol was treated with a slight excess of basic lead acetate. A voluminous, yellow precipitate was thus pro¬ duced, which was collected, washed, suspended in water, and de¬ composed by means of hydrogen sulphide. After the removal of * Air-clried