Chemical examination of calabar beans / by Arthur H. Salway.

  • Salway, Arthur H. (Arthur Henry)
Date:
[1911?]
Catalogue details

Licence: In copyright

Credit: Chemical examination of calabar beans / by Arthur H. Salway. Source: Wellcome Collection.

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    the following amounts of extract, dried at 100°, were ob¬ tained : Petroleum (b. p. 35—50°) extracted 0-38 grams = 0'76 percent. Ether Chloroform Ethyl acetate Alcohol Total 0-08 9 9 = 0T6 5 9 0T8 9 9 = 0*36 9 9 0*13 ) 9 = 0-26 9 9 2-32 9 9 = 464 9 9 3-09 9 9 6T8 ) 9 For the purpose of a complete examination of the constituents of the bean 122‘7 kilograms of finely powdered material were extracted by continuous percolation with hot alcohol. After removal of the greater part of the alcohol there remained a reddish-brown extract, amounting to 10J kilograms. This extract, in convenient portions, was mixed with water, and the mixture distilled in a current of steam. The distillate, which contained a very small quantity of essential oil, was extracted with ether, the ethereal solution being washed, dried, and the ether removed. A pale yellow oil possessing a garlic-like odour and amounting to 1*5 grams was obtained. After the above operation there remained in the steam distillation flask a large quantity of fatty oil floating on the surface of a reddish-brown aqueous liquid, which contained a brown, resinous powder in suspension. The fatty oil wras separated, washed well with water, and set aside for subsequent examination, whilst the brown resin was collected and washed with water, the washings being added to the main portion of the aqueous liquid. Isolation of Physostiymine, ^ 15-^21^2^3 • A small portion of the aqueous liquid was, in the first place, extracted successively with ether and amyl alcohol, but these solvents removed only small quantities of gummy material. The whole of the aqueous liquid was then rendered alkaline with an excess of sodium carbonate, and repeatedly extracted with ether until no further alkaloidal substance was removed by this treatment. The ethereal extracts were united, concentrated to a convenient volume, and then carefully shaken with successive portions of 5 per cent, sulphuric acid until the extract became just acid in reaction. The neutral solution of the sulphate of the alkaloid was then treated with an excess of a saturated solution of sodium salicylate, when the salicylate of the alkaloid was precipitated as an almost colourless, crystalline powder. This was collected, washed well with water, and dried in a vacuum desiccator over sulphuric acid. A further quantity of the salicylate of the alkaloid was obtained from the filtrate by rendering it alkaline with sodium carbonate, extract-