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.
Galbanum is a gum-resin obtained from Ferula galbaniflua, Boissier and Buhse (N.O. Umbelliferoe), and probably from other species.
These plants are, like those yielding ammoniacum, large Umbelliferous plants indigenous to and widely distributed over Persia. Two varieties at least of the drug are well recognised - viz. Persian, which is soft and contains fruit and stalks, and Levant, which is dried and contains slices of the root, seldom fruits or stalks. The latter is the variety at present usually met with.
Like the ammoniacum plants the galbanum plants contain, especially in the cortical portion of the stem and root, numerous schizogenous ducts that secrete a milky gum-resinous fluid.
Part of the drug is apparently obtained by natural exudation from the stem, but part is certainly produced by laying bare the root, cutting the stem off near the crown, and collecting the juice that
Volatile oil ...
Gum and impurities ...
exudes and hardens, successive slices of root being removed at intervals of several days. The former procedure would probably yield the tears that are found in commercial galbanum, whilst the slices of root found in the drug indicate the latter method as the one by which most of the drug is obtained. It is exported chiefly from the Persian Gulf ports.
Galbanum occurs in distinct tears, in small agglutinated masses, and in lump form. The tears are rounded or irregular in form, and, though they vary in size, are usually about as large as, or rather larger than, a pea. Externally they are yellowish brown or orange brown in colour, and often rough and dirty. They are not, like the tears of ammoniacum, hard, but are so soft that they can usually be squeezed flat between the finger and thumb, becoming ductile and sticky. They break easily with a granular, irregular fracture, and are opaque, yellowish, and soft internally. Sometimes the tears are more or less translucent and of a bluish green colour.
Thin transverse slices of the root are commonly found mixed with commercial galbanum; they are usually about 2 or 3 cm. in diameter and frequently bear on one side the dried secretion derived from the freshly cut surface.
The drug has a characteristic, not exactly unpleasant, aromatic odour, and a rather disagreeable, aromatic, and bitter taste. An alcoholic tincture poured into alcoholic solution of ammonia yields a brilliant blue fluorescence, indicating the presence of free umbelliferone.
Galbanum occurs also in lumps, corresponding to lump ammoniacum; these consist of yellowish or bluish green or brownish tears embedded in a brownish mass and mixed with slices of root and various foreign substances.
The student should observe
(a) The soft yellowish brown tears, occasionally bluish green,
(b) The characteristic odour,
(c) The positive result of the test for umbelliferone; and should compare the drug with ammoniacum.
Galbanum consists, apart from extraneous substances, of volatile oil (about 5 to 10 per cent.), resin (about 60 per cent.) and gum (about 20 per cent.), the residue being made up of inorganic matter (about 2 per cent., sometimes much more) and moisture (from 1 to 10 per cent).
Conrady found (1894) in a good specimen of commercial galbanum:
The resin boiled with solution of potassium hydroxide, yielded galbaresinotannol and umbellic (dioxycinnamic) acid; the latter, however, is not contained in the drug itself, but is formed from um-belliferone, the anhydride of umbellic acid which is first split off from the resin and then converted into umbellic acid. The galbaresinotannol was obtained as a brown powder.
Fig. 243. - Transverse section through a portion of the stem of Ferula galbaniflua, showing the distribution and structure of the gum-resin ducts, e, epidermis; c, collenchyma; m, gum-resin ducts; h, wood; mb, bundles in pith; magnified. (Tschirch).
Umbellic acid yields in the cold with solution of potassium hydroxide and chloroform an intense green colour. Umbelliferone when boiled with solution of potassium hydroxide and chloroform yields a similar coloration, as does also galbanum itself. Galbanum also assumes a violet red colour when warmed with hydrochloric acid; the constituent to which this characteristic reaction is due is not known.
Good qualities of the drug should yield about 40 per cent, of substances insoluble in alcohol, about 10 per cent, of moisture, and give on incineration not more than about 7 per cent, of ash.
Galbanum is used chiefly as a stimulant in plasters.