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.
Scammony root is obtained from Convolvulus Scammonia Linne (N.O. Convolvulaceoe), a twining plant indigenous to the eastern Mediterranean countries, and resembling the common bindweed but much larger. It produces a root, often of very considerable size, from which a number of slender aerial stems spring. The root, which yields by incision the gum-resin scammony, is collected and dried. It is exported from Odessa, Batoum, etc.
Scammony root is usually simple and often of large size. Small roots measure about 12 mm. in diameter and 15 to 30 cm. in length, but larger specimens attain as much as 8 or 10 cm. in thickness and a metre in length; they are nearly cylindrical in shape, tapering gradually towards the tip but slightly enlarged at the crown, and there rugged from the remains of aerial stems. The drug is of a greyish brown colour, hard, heavy, and woody, rough and furrowed externally, and often spirally twisted. Lateral rootlets occasionally spring from it and commonly split into fibrous strands. It breaks with an irregular fracture, from which short fibres (strands of wood) project. Internally the root is whitish, and the transverse section, when smoothed, exhibits an abnormal and characteristic structure. There is no distinct central wood, but the root exhibits instead several not very well-defined circles, in each of which a central portion containing groups of vessels can be distinguished from a surrounding parenchymatous portion; in the latter numerous dark points (resin cells) can be discerned with a lens. The root is invested with a thin bark, which however is not very conspicuous.1 The whole of the parenchymatous tissue contains starch.
Fig. 181. - Portion of a small Scammony root. Natural size.
The root has a characteristic odour distinctly recalling that of jalap, and especially noticeable when the surface is freshy cut; the taste is sweetish and slightly acrid. The student should observe
(a) The large size and greyish brown colour,
(b) The characteristic jalap-like odour,
Fig. 182. - Scammony root. Transverse section. (Pharmaceutical Journal).
1 For further anatomical details see Planchon and Collin, Les Drogues simples, i. 623.
(c) The remarkable structure of the transverse section,
(d) The presence of resin cells; and should compare the root with belladonna, which is usually smaller, darker externally, odourless, and has an entirely different structure.
Scammony root contains from 3 to 13 (average about 9) per cent. of a glucosidal resin which can be isolated by mixing a strong tincture with water, washing and drying the precipitated resin. The latter should be entirely, or almost entirely (97 per cent.) soluble in ether, and in this respect differs from the resin obtained in a similar manner from jalap, which is only partially (not more than 10 per cent.) soluble in that menstruum. The resin is extremely complex in composition and consists to a large extent of the glucosides and methyl-pentosides of jalapinolic acid and its methyl ester. The methylpentose obtained by the hydrolysis of the resin appears to be rhamnose and not identical with that from the resin of Orizaba root (see p. 355). The resin is hydrolysed by potassium hydroxide or barium hydroxide with production of methylbutyric, tiglic, formic, valeric, jalapinolic and other acids together with rhamnose. Jalapinolic acid has also been termed scammonolic acid. The resin also contains a small percentage of fat (palmitin, stearin, olein, linolin, etc).
The British Pharmacopoeia (1914) requires not less than 75 per cent. of the resin to be soluble in ether; the difference between this figure and that given above is due to the fact that the Pharmacopoeia permits the use of Orizaba root in the production of the resin, and that Orizaba resin is less soluble in ether (65 to 70 per cent.). When scammony resin is boiled with solution of potassium hydroxide, and the solution acidified, turbidity only, due to the fat in the resin, is produced; most other resins produce a distinct precipitate.
Scammony root contains also a little sucrose and reducing sugar, starch, β-methylaesculetin (see p. 343), dihydroxycinnamic acid, a phytosterol, the alcohol ipuranol and a trace of volatile oil. The starch occurs in grains of characteristic appearance, an important fact, as it is sometimes necessary in examining scammony to distinguish the starch of the scammony root from other starches that may possibly have been fraudulently added.
Scammony root is employed only as a source of scammony resin, which can be more economically prepared from the root than from the expensive gum-resin. Much of the commercial resin is, however, at present obtained from Orizaba root (male or woody jalap, Mexican scammony; compare p. 355).