Source, Etc

The aconite, monkshood, or wolfsbane, Aconitum Napellus, Linne (N.O. Banunculaceoe), is a perennial herb growing abundantly on the lower mountain slopes of Central Europe. It is cultivated in England as a garden plant as well as for medicinal use, and is found apparently wild in some localities, having probably escaped from cultivation. The drug has only recently been introduced into medicine, but the poisonous properties of aconite have long been known. Both the fresh leaves and flowering tops as well as the dried roots have been used, the latter alone being now official.

The plant should be cut when the flowers are beginning to expand, and the leaves and flowering tops separated from the larger stalks; they are used for the preparation of the juice and green extract of aconite.

Description

The stem, which attains a height of about 1 metre or more, is upright, smooth, and usually simple, terminating in a leafy raceme of bluish flowers.

The lower leaves are petiolate, radiately veined and deeply palmatisected, the three primary divisions extending very nearly, to the petiole; towards the upper part of the plant the petioles become shorter and the lamina less divided. They are of a dark green colour on the upper surface, paler beneath and glabrous, or nearly so.

Fig. 103.   Aconite herb. a, leaf; b, flower; c, d, petals. Three fourths natural size. (Holmes.)

Fig. 103. - Aconite herb. a, leaf; b, flower; c, d, petals. Three-fourths natural size. (Holmes).

The flower is zygomorphous; the calyx consists of five blue petaloid sepals (fig. 103, b), of which the upper (posterior) is shallow helmet-shaped; of the five petals, two only are easily found as hammer-shaped nectaries (fig. 103, c) concealed within the helmet-shaped upper sepal; the other three are small and inconspicuous (fig. 103, d); the stamens are numerous. The fruit consists of from three to five divergent follicles.

The plant has little odour, but produces slowly, when chewed, an unpleasant, acrid, burning taste.

The student should observe

(a) The characteristic shape of the leaf,

(b) The shallow, helmet-shaped sepal,

(c) The characteristic taste.

Constituents

Aconite herb contains certain alkaloidal constituents, but of the exact nature of these and the proportion in which they exist there is no very definite information. The dried leaves have been stated to contain from 0.12 to 0.96 per cent. of total alkaloid, of which a part at least is undoubtedly the highly toxic crystalline alkaloid aconitine, but to what extent other alkaloids are associated with it, and what their nature may be, is not at present known. Probably the non-toxic alkaloids picraconitine and aconine, which have been isolated from the root, are also present in the herb. (Compare ' Aconite Root').

The herb also contains aconitic acid and tannin.

Aconitic acid, C3H3(COOH)3, is a crystalline acid obtained by heating citric acid to 175°, or by heating it with water and sulphuric acid; it is widely distributed throughout the vegetable kingdom.

Uses

Aconite administered internally produces a steady fall in the body temperature, and is therefore given to alleviate certain febrile conditions; it also relieves the pain of neuralgia, and may be used internally or externally. The tincture prepared from the dry root is much more generally used than the green extract or juice made from the fresh herb. (Compare also 'Aconite Root.')

The very poisonous nature of the herb renders care necessary in tasting it.