Aconite leaves are obtained from Aconitum Napellus, Linn. (N.O. Ranunculaceae), a perennial plant growing in the mountainous districts of Europe, Asia, and North America, and cultivated in England. Both the fresh leaves and flowering tops of the plant are used. The leaves are stalked, roundish in general outline, and divided down to the leaf-stalk into three segments, each of which is sub-divided into nearly opposite, linear, acute tapering segments, the lower being the longest and somewhat spreading. The blue zygomorphic flowers are arranged in a raceme. The sepals are petaloid, and consist of a hooded or helmet-shaped upper sepal, and four smaller ones. Two of the five petals are hammer-shaped nectaries, concealed in the helmet-shaped sepal, the remaining three being much reduced, and quite inconspicuous. The stamens are indefinite. The fruit consists of three to five follicles.
Constituents.—Aconite leaves contain, when dry, from 0.12 to 0.96 per cent. of total alkaloids. The poisonous alkaloid aconitine is undoubtedly one of these, but the extent to which it occurs, and the nature of the other alkaloids that accompany it, are questions which have not yet been definitely answered. Probably both picraconitine and aconine are present. The leaves also contain aconitic acid and tannin.
Properties.—The properties of aconite leaves and flowering tops are essentially those of the alkaloid aconitine.
- Extractum Aconiti, B.P., 1885.—EXTRACT OF ACONITE.
- Prepared from the fresh leaves and flowering tops of aconite. The alkaloidal strength is very variable, ranging from 0.2 to 0.66 per cent. Dose.—15 to 60 milligrams (1/4 to 1 grain).