The water-soluble active principles of ergot / by G. barger and H.H. Dale.

  • Barger, George, 1878-1939.
Date:
[1909?]
Catalogue details

Licence: Public Domain Mark

Credit: The water-soluble active principles of ergot / by G. barger and H.H. Dale. Source: Wellcome Collection.

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    9 Further purification was effected by precipitation, in absolute alcoholic solution, with mercuric chloride. Excess of mercury being removed by sulphuretted hydrogen the filtrate yielded, to exhaustive extraction with ether, a powerfully active pressor base, soluble in water, giving an intense Millon reaction, and yielding a crystalline benzoyl-derivative which melted at 167 C.: mixed with an equal weight of synthetic dibenzoyl-p. hydroxyphenylethylamine (M. P. 170°) it melted at 168\5°. The benzoyl-derivative gave, on hydrolysis, a base, of which the physiological action corresponded closely to that of p. hydroxyphenyl¬ ethylamine. The presence of this substance, the identification of which is thus complete, accounts for practically the whole of the pressor activity of watery extracts of ergot, except for such as is due to traces of ergotoxine. The method of standardising such extracts by their effect on the blood pressure, which has been widely used and recommended, is, therefore, practically an estimation of p. hydroxyphenylethylamine. The details of the action of p. hydroxyphenylethylamine have been examined, in another connexion, by one of us in conjunction with Drs Dixon and Taylor,and the results are in course of publication. It may here be mentioned that the action of this substance on the uterus, like that on the vascular system, simulates the action of sympathetic nerves. Its presence in ergot extracts, therefore, accounts, even in the absence of ergotoxine, for that action of ergot which is most familiar in therapeutics. There can be no doubt that the p. hydroxyphenylethylamine and the trace of isoamylamine are formed from tyrosine and leucine respectively: whether they are produced entirely by the ferments of the fungus itself or in any degree by bacterial action during the not sterile process of extraction, is a point on which we hope to procure evidence. In either case the notorious variability of the official liquid extract is readily intelligible.