Source, Etc

The marshmallow, Alihoea officinalis, Linne (N.O. Malvaceae), is not uncommon in moist or marshy places in southern England, and is widely distributed in similar situations in central and southern Europe. Our supplies are derived from plants cultivated in Germany, France, and Belgium.

The roots are collected in the autumn from plants about two years old, trimmed, deprived of their cork by scraping, and dried. Sometimes the root is also split longitudinally, or cut into transverse slices.

Description

The roots as met with in commerce are generally in straight, tapering, whitish pieces about 15 or 20 cm. in length, and attaining 2 cm. or more in diameter at their upper extremity. They are usually obscurely quadrangular or rounded, with a few broad and deep longitudinal wrinkles. The surface is softly fibrous from the presence of bast fibres that have been liberated by the scraping, and bears brownish scars of lateral roots. The bark, which can readily be removed in long strips, is tough and fibrous, but the wood breaks with a short granular fracture; internally the root is whitish and starchy. It can easily be cut, and the transverse section exhibits a bark of moderate thickness, separated by a yellow sinuate cambium line from the wood. Both bark and wood possess a radiate structure that is more distinct when the surface of the section is moistened; numerous cells containing a translucent mucilage then also become visible.

The drug has a faint but characteristic odour, and a mawkish, mucilaginous taste. To improve its appearance it is sometimes limed, but this sophistication can easily be detected by rinsing the drug with 1 per cent, hydrochloric acid, filtering, and adding excess of sodium carbonate, when the liquid should remain clear.

The student should observe

(a) The fibrous bark,

(b) The yellow cambium line,

(c) The radiate structure of the wood,

(d) The presence of mucilage; and should compare the root with

Belladonna root, which closely resembles unpeeled marsh mallow root, but may be distinguished by the non-fibrous nature of the bark, by the absence of mucilage, and by the scarcely radiate structure of the wood.

Constituents

The principal constituent is mucilage, of which the root is said to contain as much as 25 to 35 per cent., but these figures require confirmation. The drug contains also an abundance of starch together with asparagin and a substance allied to lecithin. Asparagin, C4H8N203, is the amide of aspartic (amidosuccinic) acid, and is found in many plants, especially in marshmallow root and in etiolated plants.

Uses

Marshmallow root is used as an emollient and demulcent.

Fig. 159.   Marshmallow root. Transverse section. Magnified. (Moeller.)

Fig. 159. - Marshmallow root. Transverse section. Magnified. (Moeller).