Source, Etc

Cevadilla seeds are the ripe seeds of Schoenocaulon officinale, Asa Gray (N.O. Liliaceoe), a tall herbaceous plant growing on the lower mountain slopes near the eastern coast of Mexico, in Guatemala, and in Venezuela. At the time of the Spanish conquest the drug was known to the American Indians as a caustic application to wounds; it came into use in Europe much later as a parasiticide. The seeds are now chiefly used as the source of veratrine.

The plant produces a tall raceme of yellowish flowers, succeeded by small three-celled capsular fruits; as the fruit ripens it separates septicidally into three follicles, which dehisce by their ventral sutures. Each follicle contains from one to six seeds. Formerly the dried fruits were imported, but now chiefly the seeds freed from the thin, brown, papery pericarps.

Description

Cevadilla seeds are long and narrow, glossy dark brown or nearly black and about 6 mm. long, tapering to an acute point. From mutual pressure in the fruits there is usually on one side a longitudinal depression with acute edges; for a similar reason the seeds are slightly curved; the surface is finely wrinkled.

The seeds are inodorous, but have an unpleasant, bitter, and acrid taste; the powder produces violent sneezing.

The student should observe

(a) The dark colour,

(b) The long narrow shape with acute angles,

(c) The acrid taste.

Constituents

The seeds contain several alkaloids of which cevadine, C32H49N09 (also called crystalline veratrine), is the most important and the most toxic; it is easily hydrolysed by alkalies yielding cevine and methylcrotonic acid. Veratridine (also called veratrine) accompanies cevadine in the seeds; it is amorphous and yields veratric acid and verine when hydrolysed. Both cevadine and veratridine are toxic and sternutatory. Other alkaloids of less importance are sabadilline (cevadilline), sabadine, sabadinine, and sabatrine, the latter being said to be only a mixture.

Fig. 101.   Cevadilla seed. a, flower, magnified. 6, stamen, magnified. c, fruit, magnified. d, e, fruit after dehiscence, natural size. f, g, h, i, seeds, natural size; k, l, m, enlarged; n, cut longitudinally. (Luer ssen.)

Fig. 101. - Cevadilla seed. a, flower, magnified. 6, stamen, magnified. c, fruit, magnified. d, e, fruit after dehiscence, natural size. f, g, h, i, seeds, natural size; k, l, m, enlarged; n, cut longitudinally. (Luer-ssen).

Commercial veratrine is a mixture of these alkaloids and consists chiefly of cevadine and veratridine; the former may readily be obtained from it by dissolving in alcohol, adding water until the solution becomes faintly opalescent and setting aside to crystallise.

Keller (1895) found 4.25 per cent. of alkaloid in the seeds.

Uses

Cevadilla seeds (and veratrine) act both internally and externally as a powerful irritant. This primary effect is followed by depression, and, when used externally, loss of sensibility; hence ointment of veratrine is used to relieve neuralgic pains, etc. Veratrine is employed also as a parasiticide, but is seldom administered internally.