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.
The sweet flag or sweet sedge, Acorus Calamus, Linne (N.O. Aroideae), is a native of Eastern Europe and Central
Asia, but has become widely diffused by cultivation. It has established itself in England as a wild plant on the edges of lakes and streams. In dry summers large quantities are collected in East Prussia and Galicia.
The rhizome has long been esteemed as a most valuable medicine in India, whence probably its use spread to Europe.
Fig. 212. - Sweet Flag rhizome. A, upper surface, showing leaf-scars. B, under surface, showing root-scars. Natural size.
The long, creeping, horizontal rhizome is collected in the autumn, trimmed, cut into pieces 10 cm. or more in length, and dried. Sometimes it is partially deprived of the outer cork layer by peeling or scraping; but this is inadvisable, as the peeled rhizomes yield less volatile oil than the unpeeled.
The rhizome commonly occurs in pieces varying from 5 to 15 cm. or more in length and from 1 to 2 cm. in thickness. They are covered with a thin brownish cork and are much shrunken bearing deep longitudinal wrinkles. They are marked on the upper surface with large triangular leaf-scars that encircle the rhizome, springing from each side alternately. To these scars the fibrous leaf-traces are sometimes attached. The under surface bears an irregular zigzag line of small raised root-scars that are circular and exhibit a central stele surrounded by a narrow cortex. The rhizome produces an occasional slender lateral branch which is distinctly marked with the scars of leaves and roots.
The scraped rhizome is of a pale brownish buff colour, has a roughish surface, and bears less conspicuous scars of leaves and roots.
The drug breaks with a short corky fracture, and is pale brown, or nearly white, and spongy internally. The section exhibits a large stele separated by a yellowish line from a thick cortex of similar appearance. Both stele and cortex are traversed by numerous small, oval, scattered, fibro-vascular bundles.
Fig. 213. - Sweet Flag rhizome. Transverse section, magnified 3 diam. a, cortex; v, endodermis b, stele; y, vascular bundles. (Berg).
The freshly fractured surface has an agreeable aromatic odour. The taste is disagreeably bitter and pungent.
The student should observe
(a) The large triangular leaf-scars,
(b) The zigzag line of root-scars,
(c) The spongy texture,
(d) The bitter, pungent taste.
Sweet flag rhizome contains from 1.5 to 3.5 per cent. of an aromatic volatile oil, the chief aromatic constituent of which is asaryl aldehyde. It contains also an amorphous bitter principle, acorin, yielding by oxidation acoretin and by treatment with acids or alkalies volatile oil and sugar. Certain alkaloidal substances (choline, trimethylamine) appear also to be present, but they require further investigation. The drug contains an abundance of starch and a little tannin.
The drug has stimulant and tonic properties; it has been used for ague and for atonic dyspepsia.