Source, Etc

The leaves of the thornapple, Datura Stramonium, Linne (N.O. Solanaceoe), have already been described (p. 46), and the attention of the student has been directed to the white flower and spiny fruit. The latter when ripe is about the size of a walnut, and dehisces septifragally, the four walls separating from apex to base. The fruit is two-celled in its upper part, but, from the presence of spurious dissepiments, four-celled near the base. It contains a large number of seeds, which are collected when ripe.

Source Etc 147Fig. 95.   Thornapple seed. A, showing the pitted surface; B, longitudinal section, showing curved embryo. Magnified. (B, after Moeller.)

Fig. 95. - Thornapple seed. A, showing the pitted surface; B, longitudinal section, showing curved embryo. Magnified. (B, after Moeller).

Description

Stramonium seeds are dull dark brown or, more commonly, nearly black, flattened and distinctly reniform in outline, averaging about 3 mm. in length. The hilum is distinct in the form of a light spot on the concave edge. The seed-coat is marked with distinct, but not sharp, reticulate depressions, and, in addition, is minutely pitted.

If the seed is split parallel to one of the flattened sides, the crook-shaped embryo may be distinguished embedded in an oily endosperm; in transverse section the embryo appears rounded, and will, owing to its curved shape, be cut at two, or possibly three, different points.

The odour of the seeds is scarely perceptible until they are crushed, then it becomes rather disagreeable; the taste is bitterish and oily.

The student should observe

(a) The size, reniform outline, and dark colour,

(b) The reticulated and pitted surface,

(c) The curved embryo embedded in an oily endosperm.

Constituents

In 1833, two years after the discovery of atropine, Geiger and Hesse extracted from stramonium seeds an alkaloid to which they gave the name of daturine. Planta proved this alkaloid to be atropine, and Schmidt subsequently showed that these seeds contain the alkaloid hyoscyamine, associated with a small proportion of atropine and scopolamine (hyoscine). Farr and Wright found English grown seed to yield from 0.16 to 0.28 (average 0.22 per cent.) of alkaloid, but as much as 0.5 per cent, has been recorded. In addition, the seeds contain from 15 to 30 per cent, of fixed oil containing daturic and other acids. The drug yields about 2 per cent, of ash.

Uses

In this respect stramonium seeds resemble stramonium leaves. An extract of the seeds is given in spasmodic affections of the respiratory organs.