The chief constituent of Wormseed is a crystalline principle, Santonin, to which the anthelmintic property of the drug is due. Santonin attains its maximum 2.3 to 3.6 per cent in July and August; after the flowerheads have expanded, it rapidly diminishes in quantity. It is extracted from the flower-heads by treating them with Milk of Lime, the Santonin being converted into soluble calcium santonate. It occurs in colourless, shining, flat prisms, without odour and almost tasteless at first, but afterwards developing a bitter taste. It is sparingly soluble in water, but soluble in alcohol and ether.
Wormseed also contains a crystalline substance, Artemisin, and a yellow volatile oil consisting of Cineol, to which its odour is due.
Medicinal Action and Uses :
Wormseed is one of the oldest and most common anthelmintics, especially for children. In domestic practice the seeds are used powdered, combined with honey or treacle, the dose of the seeds taken thus in substance being 10 to 30 grains. The seeds have also been employed in infusion or decoction, but in these forms their bitterness is a strong objection. As a general rule, however, the crude drug Wormseed is seldom administered, its active constituent Santonin being employed. It acts as a direct poison to parasites, and is used as a remedy for round-worms, which it rapidly expels; it has also an effect on thread-worms to a lesser degree, but has no action on tapeworms. It is usually administered as a powder or in lozenges, not in solution, and is often given with calomel, or compound powder of scammony.
Preparations :
Several cases are on record of fatal poisoning by Santonin, and Santonin rendered yellow by exposure to direct sunlight is sometimes preferred, it being stated to be less poisonous. It is known as yellow Santonin, or Photosantonin.
Even small doses of Santonin will produce remarkable effects on the vision, appreciation of colour being so disturbed that objects appear to have a yellowish tinge, which is sometimes preceded by a faint colour. Santonin may also cause headache, nausea and vomiting, and in large doses, epileptiform convulsions.
