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.
Asafetida is a gum resin obtained from the root of Ferula fcetida, Kegel, F. rubricaulis, Boissier (N.O. Umbelliferoe), and probably other species. These plants, like those yielding ammoniacum and galbanum, are large Umbelliferous plants growing in eastern Persia and western Afghanistan. In the cortex of the stem, and especially in that of the root, there are numerous large, schizogenous ducts filled with a milky, gum-resinous emulsion; these when wounded discharge their contents, which then gradually acquire by evaporation a firmer consistence.
Part of the drug is certainly collected in a manner similar to that in which part at least of commercial galbanum is obtained - viz. by laying bare the root of the plant and cutting off the stem close to the crown; the emulsion that flows from the cut surface is allowed to harden, for which purpose the root is protected by a dome-like covering of sticks and leaves; the hardened gum-resin is then scraped off, a slice of the root cut off, and the juice again allowed to exude, and so the process is repeated. Some is probably obtained by incising the stem.
Herat and Kandahar are the centres of the asafetida trade. The drug is exported from Bunder Abbas and other ports on the Persian Gulf, partly also from Bombay, mostly in large tin-lined cases, but a small quantity arrives as a pasty mass in tins or hides.
Asafetida occurs in three forms, viz.: paste, tear and mass (block or lump). Paste and tear are the purer forms, but the bulk of the drug is mass.
The tears, some of which are separate, some more or less agglutinated together, are rounded or flattened, and vary from 1 to 3 cm. in diameter. They are of a dull yellow or sometimes dirty grey colour; some darken on keeping, finally becoming reddish brown, but others retain their original colour for years, thus indicating some difference in the drug. Probably the red variety is derived from F. foetida, the white from F. rubricaulis. When fresh they are usually tough at ordinary temperatures, becoming harder when cooled and softer when warmed. Internally they may be yellowish or milky white, translucent or opaque; the freshly exposed surface, may gradually, pass through a very characteristic change of colour, becoming first pink, then red, and finally reddish brown (F. foetida), or may remain nearly white (F. rubricaulis). The drug has an intense, penetrating, persistent, alliaceous odour, and a bitter, acrid, alliaceous taste.
Mass asafetida consists of the tears agglutinated into a more or less uniform mass and mixed with varying quantities of extraneous substances such as stones, slices of the root, earthy matter, calcium carbonate, calcium sulphate, etc.; it is generally much inferior to the tears.
Asafetida contains no free umbelliferone (compare ' Galbanum'), but yields it when boiled with hydrochloric acid; a reaction which serves to distinguish it from a variety of the drug met with in Bombay yielding no umbelliferone. From galbanum the tears of asafetida may also be distinguished by the green colour the freshly fractured surface assumes when it is touched with nitric acid diluted with an equal volume of water, or by the bright red or brownish red colour with sulphuric acid, changing to violet when the acid is washed off with water.
Asafetida consists principally of volatile oil, resin, and gum.
Good samples yield from 10 to 17 per cent, of volatile oil, from 40 to 64 per cent, of resin, about 25 per cent, of gum, and 1.5 to 10 per cent of ash. The amount of mineral matter in mass asafetida may rise to 60 per cent, or exceptionally even more; fine tears may contain as little as 1.5 per cent.
The resin consists of ferulic acid combined with asaresinotannol; although the drug contains no free umbelliferone, it easily yields that substance by the action of sulphuric or hydrochloric acid on the ferulic acid and on the resorcin produced simultaneously from the resin.
The volatile oil contains pinene together with various disulphides, C7H14S2, C11H10S2, C10H18S2, etc., the percentage of sulphur varying from 17 to 37.
Asafetida is a powerful nervine stimulant, and is used in the nervous disorders of hysteria. It has also a well-marked stimulant action on the bowel, and is employed to expel flatulence and relieve constipation. Much of it is exported to the continent and also to the United States, where is is used on the cattle ranches.