Source, Etc

Wormseed consists of the small, unexpanded flower-heads of Artemisia maritima, var. a-Stechmanniana, Besser (N.O. Compositoe). The species has, in numerous varieties, an extremely wide distribution, from the Bay of Biscay to Chinese Mongolia. The variety from which part at least of the drug is obtained, and which, according to some botanists, should be considered a distinct species (A. Cina, Berg), grows in enormous quantities in the deserts of the Kirghiz in Turkestan, especially near the town of Chimkent (which lies to the north of Taschkent and some seventy miles east of the Sir Daria river) where factories have been erected, in which large quantities of santonin are produced from the wormseed collected in the vicinity. Comparatively little of the crude drug is now exported.

The plant is small and woody, with numerous, erect branches about 40 cm. long, on which very small flowerheads are borne. These are stripped from the stems before they expand, and dried. They are collected in July and August by Kirghiz and other tribes and brought to Chimkent.

Wormseed has long been used as an anthelmintic; it was employed in Italy under the name of semenzina (diminutive of semenza = seed) under the belief that it consisted of small seeds. From the word semenzina is derived the name ' semen cinae,' by which the drug is often known; semen contra (another of its names) is an abbreviation of * semen contra vermes.' The drug appears at first sight to consist of a number of small, brownish, ridged seeds the true nature of which becomes apparent when they are dissected.

Description

The flowerheads are of a greenish yellow colour, but turn brown by drying and keeping. They are only about 1.5 mm. long, elongated ovoid in shape, and somewhat angular; their surface is shining and glabrous, or at most only slightly hairy.

The involucre consists of imbricated ovate or lanceolate bracts, furnished with a distinct keel, on each side of which are shining oil-glands; the latter, however, are not easily seen even under a powerful lens. After soaking in water the bracts can be removed with dissecting needles, and in the centre from three to six very minute, unexpanded, tubular florets will be found; they are completely enclosed by the upper bracts of the involucre, and bear minute oil-glands on the lower portion of the corolla. The drug exhales, when crushed, an agreeable, aromatic odour, and possesses a bitter, aromatic, camphoraceous taste. It frequently contains a considerable admixture of fragments of the leaves and very slender flower stalks.

The student should soak the wormseed in water for twenty-four hours, and then dissect a flowerhead with the aid of the dissecting needles and a lens. He should note

(a) The imbricated, keeled, glabrous bracts,

(b) The minute florets enclosed within them,

(c) The characteristic odour and taste.

Constituents

Wormseed contains a volatile oil and two crystalline principles, viz. santonin, to which the anthelmintic property of the drug is due and artemisin. The santonin attains its maximum (2.3 to 36 per cent. - Ehlinger, 1885) in July and August. After flowering it rapidly disappears.

Santonin, C15H1803, forms colourless bitter crystals that are very slightly soluble in water but unite with alkalies, forming soluble salts of monobasic santonic acid, C15H10O4. Exposed to light, santonin assumes a yellow colour (photosantonin).

Santonin is extracted from the flowerheads by treating them with milk of lime, the santonin being converted into soluble calcium santonate. From the filtrate excess of calcium is removed by a current of carbon dioxide, and the calcium salt is converted into the sodium salt by means of sodium carbonate. The liquid is filtered warm and the santonin separated by the addition of sulphuric acid. It is purified by decolorisation with charcoal and recrystallisation from hot alcohol.

Fig. 45.   Flowerhead of Artemisia. A, entire, showing imbricated bracts with external glands: B, cut longitudinally, showing florets. Magnified.

Fig. 45. - Flowerhead of Artemisia. A, entire, showing imbricated bracts with external glands: B, cut longitudinally, showing florets. Magnified.

(Luerssen).

Substitutes, Etc

From time to time a variety of wormseed containing little or no santonin appears on the market; it may be recognised by the more or less hairy nature of the bracts.

Use

Wormseed is now seldom administered, but santonin is often employed as an anthelmintic for round worms which it rapidly expels; it has less effect upon thread-worms and no action on tape worms. It produces remarkable disturbances of vision, objects appearing first blue and then yellow, and the absorbed santonin renders the urine intensely yellow if acid or purplish if alkaline.

Certain other species of Artemisia (e.g. A. gallica, Willdenow) have anthelmintic properties. American wormseed (A. anthelmintica) is cultivated in California.