Chemical Composition—Stenhouse[698] discovered in broom tops two interesting principles, Scoparin, C₂₁H₂₂O₁₀, an indifferent or somewhat acid body, and the alkaloid Sparteine, C₁₅H₂₆N₂, the first soluble in water or spirit and crystallizing in yellowish tufts, the second a colourless oily liquid heavier than water and sparingly soluble in it, boiling at 288° C.
To obtain scoparin, a watery decoction of the plant is concentrated so as to form a jelly after standing for a day or two. This is then washed with a small quantity of cold water, dissolved in hot water and again allowed to repose. By repeating this treatment with the addition of a little hydrochloric acid, the chlorophyll may at length be separated and the scoparin obtained as a gelatinous mass, which dries as an amorphous, brittle, pale yellow, neutral substance, devoid of taste and smell. Its solution in hot alcohol deposits it partly in crystals and partly as jelly, which after drying are alike in composition. Hlasiwetz showed (1866) that scoparin when melted with potash is resolved, like kino or quercetin, into Phloroglucin, C₆H₆O₃, and Protocatechuic Acid, 2 C₇H₆O₄.
The acid mother-liquors from which scoparin has been obtained when concentrated and distilled with soda, yield besides ammonia a very bitter oily liquid, Sparteine. To obtain it pure, it requires to be repeatedly rectified, dried by chloride of calcium, and distilled in a current of dry carbonic acid. It is colourless, but becomes brown by exposure to light; it has at first an odour of aniline, but this is altered by rectification. Sparteine has a decidedly alkaline reaction and readily neutralises acids, forming crystallizable salts which are extremely bitter. Conine, nicotine, and sparteine are the only volatile alkaloids devoid of oxygen hitherto known to exist in the vegetable kingdom.
Mills[699] extracted sparteine simply by acidulated water which he concentrated and then distilled with soda. The distillate was then saturated with hydrochloric acid, evaporated to dryness, and submitted to distillation with potash. The oily sparteine thus obtained was dried by prolonged heating with sodium in a current of hydrogen, and finally rectified per se. Mills succeeded in replacing one or two equivalents of the hydrogen of sparteine by one or two of C₂H₅ (ethyl). From 150 lb. the (dried?) plant, he obtained 22 cubic centimetres of sparteine, which we may estimate as equivalent to about ½ per mille.
Stenhouse ascertained that the amount of sparteine and scoparin depends much on external conditions, broom grown in the shade yielding less than that produced in open sunny places. He states that shepherds are well aware of the shrub possessing narcotic properties, from having observed their sheep to become stupified and excited when occasionally compelled to eat it.
The experiments of Reinsch (1846) tend to show that broom contains a bitter crystallizible principle in addition to the foregoing. The seeds of the allied Cytisus Laburnum L. afford two highly poisonous alkaloids, Cytisine and Laburnine, discovered by A. Husemann and Marmé in 1865.
Uses—A decoction of broom tops, made from the dried herb, is used as a diuretic and purgative. The juice of the fresh plant, preserved by the addition of alcohol, is also administered and is regarded as a very efficient preparation.
SEMEN FŒNI GRÆCI.
Semen Fœnugræci; Fenugreek; F. Semences de Fenugrec; G. Bockshornsamen.
Botanical Origin—Trigonella Fœnum græcum L., an erect, sub-glabrous, annual plant, 1 to 2 feet high, with solitary, subsessile, whitish flowers; indigenous to the countries surrounding the Mediterranean, in which it has been long cultivated, and whence it appears to have spread to India.