Alstonia. Br. Alstonia.
"Alstonia is the dried bark of Alstonia scholaris, E. Br., and also of Alstonia constricta, F. Muell." Br. Dita Bark; Australian Fever Bark; Bitter Bark.
Under Alstonia the British Pharmacopoeia recognizes the dried barks of Alstonia scholaris (L.) R. Br. (Echites scholaris L.), of India and the Philippine Islands, and Alstonia constricta F. Muell., of Australia, two apocynaceous trees whose barks are quite dissimilar in appearance, and, as far as our present knowledge goes, contain different alkaloids. These barks are respectively described as follows:
"Bark of Alstonia scholaris usually in irregular fragments, three to twelve millimetres thick; texture somewhat spongy, fracture short and coarse; external layer unevenly rough and fissured, brownish-grey with occasional blackish spots; internal layer bright buff. Transverse section shows numerous small medullary rays in inner layer. Almost odorless; taste bitter. Bark of Alstonia constricta usually in curved pieces or quills about sixty millimetres wide, and twelve millimetres thick. Periderm from two and a half to six millimetres thick, rusty brown, strongly rugose, with large deeply fissured reticulations. Bark internally cinnamon-brown, with strong, coarse longitudinal striae. Transverse section shows dark-brown periderm covering the inner orange-brown tissues, in which numerous small shining particles can be seen with a lens. Fracture short and granular in outer layers, fibrous in inner. Slight aromatic odor; taste very bitter." Br.
From the bark of Alstonia scholaris M. Gruppe extracted an uncrystallizable, hygroscopic, bitter principle, ditaine. (J. P. C., 4e ser., xviii, 225; xix, 84; P. J., Aug., 1875.) Harnack (Ber. d. Chem. Ges., 1878) first obtained ditaine in pure crystallized form, and gave it the formula C20H30N2O4. O. Hesse (P. J., Oct. 23, 1880) finds in dita the following principles: three alkaloids: ditamine, O16H9O2N, the relative amount of which he estimates at 0.04 per cent.; echitamine, C22H28O4N2 + H20 (identical, according to Hesse, with Harnack's ditaine); and echitenine, C20H27O4N. Of these, the second is the strongest base, and resembles ammonia in its chemical characters; Hesse considers it with one molecule of water to form the hydroxide of a strong basic radical, echitammonium, C22H29O4N2. The solutions of echitammonium hydroxide are so strongly basic that they precipitate the hydroxides of copper, iron, aluminum, and lead, and decompose sodium and potassium chlorides, liberating the corresponding hydroxides. Hesse considers echitammonium the most strongly basic of all the alkaloids. Hesse also obtained by extraction with petroleum benzin echicaoutchin, echiretin, echicerin, echitin, and echitein, of which the three last mentioned are crystalline.
From Alstonia constricta, F. V. Müller and A. Rummel obtained alstonine. Oberlin and Schlagdenhauffen found in 1879 another alkaloid, alstonicine. Hesse subsequently analyzed the bark and found alstonine, the chlorogenine of a former investigation, which has the composition C21H20O4N2, prophyrine, C21H25O2N3, and alstonidine. The alkaloids and their salts in acidulated solutions show decided blue fluorescence.
Uses.—This drug has been used for many years in Australia and the Philippine Islands in the treatment of malarial and other fevers, as well as a simple bitter. The alkaloid ditaine has been scientifically studied by Harnack (A. E. P. P., 1877, xvii, p. 126), who finds that it has a paralyzing effect upon the endings of the motor nerve similar to that produced by curara. In large dose it also paralyzes the cardio-inhibitory nerves and lowers blood pressure. There is nothing in this study, which is, as far as we know, the only scientific investigation of the drug which has been made, to explain any action in malaria. Nevertheless some of the clinical reports, especially from the eclectic physicians, have been extremely laudatory, vaunting it even as a substitute for quinine.
Dose, two to four grains (0.13-0.25 Gm.).