This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Ammoniacum is a gum-resin exuded from the flowering and fruiting stem of Dorema Ammoniacum, D. Don (N.O. Umbelliferoe), and probably other species, distributed throughout Persia and extending into southern Siberia.
The drug is collected chiefly in central Persia.
The stems of the ammoniacum plants contain, especially in the cortex, numerous, large, schizogenous ducts full of a milky secretion. In the summer, when the plant is fruiting, it is visited by numbers of beetles, which puncture the stem and cause an abundant exudation of the secretion in the form of milky drops, some of which harden on the stem, whilst others drop on to the ground. It is collected, sorted, and exported from the Persian Gulf ports.
Ammoniacum occurs in commerce in two forms - viz. tear ammoniacum and lump ammoniacum, the former being alone official.
The tears are small, rounded or nodular masses varying usually from 0.5 to 3 cm. in diameter. When fresh they are of a pale dull yellow colour, which, however, darkens by keeping. They are hard and brittle when cold, but soften when warmed. Internally the tears are opaque, and vary in colour from milky white to pale brownish yellow, the freshly fractured surface having a waxy lustre. The drug has a characteristic but not alliaceous odour, and a bitter, acrid taste. Triturated with water it forms a white emulsion, which is coloured deep orange red by a solution of chlorinated soda, yellow by solution of potash, and, transiently, faintly violet by ferric chloride. The latter reaction, although not strong, should be noted, as it depends upon the presence of a constituent (salicylic acid) that is absent from other similar gum-resins, and is characteristic therefore of ammoniacum; a more distinct coloration is obtained by shaking the emulsion with asbestos, filtering clear and adding to the filtrate a drop of solution of ferric chloride.
Lump ammoniacum consists of agglutinated, whitish, yellowish grey or bluish grey tears, mixed with varying quantities of extraneous substances, such as stones, dirt, stems and other debris of the plant and occasionally the broad, flat mericarps of the fruit, the presence of which indicates the time at which the drug has been collected. The substance of the tears agrees with the description of the tears already given.
Good qualities of lump ammoniacum consist of tears varying in size from a pea to a hazel-nut or even larger, with a little intervening dark-coloured ground substance, and but few pieces of stem, fruits, etc. Intermediate forms composed of more or less agglutinated tears also occur.
If about 1 gramme of the drug is boiled for a few minutes with 20 c.c. of equal volumes of hydrochloric acid and water, and the solution filtered into water made strongly alkaline with ammonia, no blue fluorescence should be developed. This reaction indicates the absence of umbelliferone (which, in alkaline solution, exhibits a strong blue fluorescence) and distinguishes Persian ammoniacum from galbanum, asafetida, and African ammoniacum, all of which yield umbelliferone. Free umbelliferone may also be tested for by adding an alcoholic tincture of ammoniacum to an alcoholic solution of ammonia.
The student should observe
(a) The clean, hard tears, which do not crumble between the fingers, (6) The characteristic odour,
(c) The positive result of the test for salicylic acid,
(d) The negative result of the test for umbelliferone; and should compare the drug with selected tears of galbanum, which are much softer, have a distinctive odour, and yield a positive result with test for umbelliferone.
Ammoniacum consists of volatile oil 0.1 to 1.0 per cent., resin (about 65 to 70 per cent.), gum (about 20 per cent.), moisture (2 to 12 per cent.), ash (1 per cent.), and insoluble residue (3.5 per cent.).
Luz (1893) found that the resin could be separated into two portions, one consisting of a resene not attacked by caustic alkalies, and the other and larger portion decomposed by long-continued boiling with solution of caustic potash into salicylic acid and a resin-alcohol, ammoresinotannol, which was obtained as a brownish powder. The resin chiefly consists therefore of ammoresinotannol combined with salicylic acid.
The gum is allied to acacia gum.
Luz was unable to detect sulphur in either the volatile oil or the resin, although that element had previously been reported present in ammoniacum.
The drug contains also traces of free salicylic acid, which is the source of the violet colour produced when ferric chloride is added to an aqueous emulsion.
Good qualities of the drug yield about 3 per cent, of ash and 65 per cent, of resin.
Ammoniacum is a stimulant, and, being excreted by the bronchial mucous surfaces, stimulates and disinfects the secretion. It is used as a disinfectant expectorant in chronic bronchitis with profuse discharge, and in plasters as a stimulant to the skin.
The official or Persian ammoniacum is distinguished from African ammoniacum, said to be obtained in Africa from Ferula communis, Linne, var. brevifolia, by the orange red colour it yields with solution of chlorinated soda, and also by yielding a negative result with the tests for umbelliferone.