Alstonia consists of the dried bark of Alstonia scholaris, R. Brown (N.O. Apocynaceae), a tree growing in India and the Philippine islands, and of A. constricta, F. Mueller, which grows in Australia, and is known as Australian fever bark or dita bark. The bark of A. scholaris and preparations made therefrom are sanctioned for use in India and the Eastern Colonies, while the use of the bark of A. constricta and its preparations is limited to the Australasian Colonies. The bark of Alstonia scholaris occurs in single quills, or in irregular curved pieces, and varies exceedingly in size and appearance. That from older stems or branches is commonly in small curved or channelled pieces, or quills, and is of a light yellowish-brown colour, rough and irregularly fissured, and spongy externally; internally it is darker. Such pieces break with a short fracture, the section exhibiting a narrow inner portion (cortex and secondary bast), traversed by numerous fine medullary rays, and a spongy outer portion (cork), the extent of which varies in the various pieces of the drug. The bark from young branches bears scattered pale lenticels, and is very fibrous. Both kinds contain numerous pitted sclerenchymatous cells, laticiferous vessels, and prismatic crystals of calcium oxalate, but young bark contains abundant pericyclic fibres which are seldom visible in old bark. The drug has a bitter taste, but no odour. The bark of A. constricta occurs in quills or channelled pieces, often of considerable size. The outer surface is brown or yellowish-brown in colour, and deeply fissured, both longitudinally and transversely, the inner surface being cinnamon-brown in colour, and coarsely striated. The transverse section exhibits an abundant dark brown cork, within which is a yellowish-brown layer (secondary bast); the latter exhibits under the microscope abundant bast fibres, in tangentially arranged groups. The drug has a very bitter taste, and yields a yellowish aqueous infusion, with a well-marked blue fluorescence.
Constituents.—The chief constituents of the bark of Alstonia scholaris are the alkaloids ditamine, echitenine, and echitamine. Ditamine, which is present to the extent of about 0.04 per cent., has the composition C16H19NO2, and has been obtained as a bitter crystalline powder (melting-point, 75°); echitenine, C20H27NO4 (melting-point, 120°), is an amorphous bitter powder; echitamine or ditaine, C22H28N2O4, H2O, is a white powder, the crystals having the formula C22H28N2O4, 4H2O. The following constituents have also been extracted from the bark:—Echicerin, a crystalline non-nitrogenous body; echicaoutchin, an amorphous substance resembling caoutchouc; echitin and echitein, both of which are crystalline, and echiretin, which is amorphous; all these constituents appear to be devoid of marked therapeutic properties. The chief constituents of the bark of Alstonia constricta are the alkaloids alstonine (chlorogenine), C21H20N2O4, 3 1/2 H2O, and porphyrine, C21H25N3O2 (?). It also contains porphyrosine and alstonidine, about which little definite is known. Porphyrine is amorphous and colourless, and shows a blue fluorescence in acid solution.
Action and Uses.—Alstonia is employed in India and the Eastern Colonies for malarial conditions. Its value in this respect cannot be compared with that of cinchona bark, although it produces no bad effects, such as cinchonism. Occasionally it is employed as a bitter tonic and anthelmintic, and as a remedy in chronic diarrhoea. For administration the infusion or the tincture may be used.
- Infusum Alstoniae, I.C.A.—INFUSION OF ALSTONIA.
- Alstonia, bruised, 5; distilled water, boiling, 100. Infusion of alstonia is official in India and the Australasian and the Eastern Colonies, where it is used as a bitter tonic, in malaria and chronic diarrhoea. Dose.—15 to 30 mils. (1/2 to 1 fluid ounce).
- Tinctura Alstoniae, I.C.A.—TINCTURE OF ALSTONIA.
- Alstonia, in No. 20 powder, 12.5; alcohol (60 per cent.), 100. Tincture of alstonia is official in India and the Australasian and Eastern Colonies. It is used chiefly as a bitter. Dose.—2 to 4 mils (1/2 to 1 fluid drachm).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.