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The Bark of Alstonia Spectabilis.

Botanical name:


Alstonia bark, the "cortex Alstoniae" of pharmacognosists, is nearly allied to dita bark. This bark, which in Java is called "poelé" comes from the Alstonia spectabilis, R.Br., a species which from its characteristic properties has been named by De Candolle, Blaberopus venenatus. This Alstonia grows in Timor, the Moluccas, and in the eastern parts of Java, especially in the neighborhood of Malang.

Wiggers, on his "Pharmacognosie," ("Pharmakognosie," 5th edit. 1864, p. 358), gives an extremely true description of this bark, to which I would refer.

Poelé bark differs from dita bark not alone by its extraordinarily bitter taste, but also in its anatomical structure. For comparison a specimen of dita bark was obtained, which was apparently stem bark, and a branch bark of the other kind. Herr Professor Ahles, who has examined both barks microscopically, kindly tells me that the difference in the structure of the two barks does not depend alone upon their age, but also upon the peculiarities of the respective plants.

Formerly the poelé bark was used in Java against fever with favorable results, and in Batavia especially it came much into use for this purpose. Apothecary Scharlee ("Geneeskundige Tijdschrift voor Nederl. Indie," vol. x, p. 209, 1863,) there examined this bark and found in it a special alkaloid, which he named "alstonine." This was occasionally prepared in Batavia, but does not appear to have ever come into use either in the hospitals or in private practice.

As the name "alstonine" had already been given to a substance obtained from the Australian Alstonia, I have before proposed that Scharlee's alkaloid might be named "alstonamine." In the following remarks I shall use this name for the alkaloid in question.

Scharlee obtained the alkaloid by extracting the coarsely powdered bark with alcohol, and after previous filtration precipitating the tincture with tannic acid. The white flocculent tannate was washed with water, suspended in alcohol, and decomposed with freshly precipitated lead hydrate. The alcoholic solution, upon evaporation over sulphuric acid, yielded the alkaloid in brilliant oblique rhombs and prisms. In its reactions it presented relatively great similarity to ditamine. But from this alkaloid it differs, as also from echitenine, by its power of easily crystallizing.

Further, that it cannot be echitammoniumhydroxide is evident from the following experiment. Freshly precipitated echitammonium tannate in alcoholic solution was treated with freshly precipitated lead hydrate, but was not decomposed by it. This result is not surprising,. as it is known that echitammoniumhydroxide separates lead hydrate from its combinations.

Consequently, there is in alstonamine an alkaloid differing from the alkaloids of dita bark (this Journal, 1880, p. 620). In order to obtain further information upon the nature of this alkaloid, I undertook an investigation of poele bark. I am indebted for a specimen to Professor Wiggers, who had obtained it some time ago direct from Batavia, possibly from Scharlée himself.

I first prepared an alcoholic extract from 50 grams of powdered bark. This was treated with dilute acetic acid, when a resinous mass was left which contained a considerable quantity of echicerin (this Journal, 1876, p. 370). The clear filtered acetic solution was then supersaturated with soda, shaken with ether, and this treated with acetic acid. After supersaturating this solution with ammonia the-base removed from it by pure ether weighed 0.066 gram. It was found to be identical with ditamine.

The liquid left after treatment with ether was next supersaturated with potassium hydrate and shaken with chloroform. Upon evaporation of the chloroform solution, after washing with water, there remained a brown amorphous residue, which after treatment with hydrochloric acid gave 0.423 gram of echitammonium chloride.

The mother liquor was then again supersaturated with potassium hydrate and shaken with chloroform, which now upon evaporation yielded 0.042 gram of a mixed residue, consisting of an amorphous alkaloid and one crystallizing readily from chloroform. The crystals were concentrically grouped prisms and behaved towards nitric acid like ditamine. The substance was repeatedly dissolved in chloroform and upon evaporation of the solution obtained again unaltered. The small quantity of this substance which I thus obtained, though not sufficient for further experiment, was sufficient to ascertain that it was not ditamine, echitenine or echitammoniumhydroxide. As besides tills no other crystallizable alkaloid could be observed in this alstonia bark, I assume that these crystals were actually Scharlée's alstonamine.

As to the amorphous portion, in which these crystals were imbedded, it corresponded in its behavior with echitenine.

The quantity of bases present in 100 parts poelé bark accordingly amounted to

0.132 Ditamine.
0.808 Echitammoniumhydroxide.
0.080 Echitenine and Alstonamine.

In order, therefore, to obtain a sufficient quantity of alstonamine for a thorough investigation a considerable quantity of poele bark would be required. Unfortunately I have not been able to procure such a quantity, so that I must desist from the further examination of this alkaloid.

One result of especial interest is that the bark in question contains more than six times as much echitammoniumhydroxide as does dita bark, in which I found 0.13 per cent. It may be observed that the action of this alkaloid and its chloride upon the animal organism is similar to that of curare, so that it probably follows that persons who are treated with this bark for the relief of intermittent fever would undergo a more or less powerful poisoning.—Pharm. Jour. and Trans., Nov. 6, 1880, from Ann. d. Chem.

The American Journal of Pharmacy, Vol. 53, 1881, was edited by John M. Maisch.

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