Chemical Composition—The bitter taste and highly poisonous action of nux vomica are chiefly due to the presence of Strychnine and Brucine. Strychnine, C₂₁H₂₂N₂O₂, was first met with in 1818 by Pelletier and Caventou in St. Ignatius’ Beans, and immediately afterwards in nux vomica. It crystallizes from an alcoholic solution in large anhydrous prisms of the orthorhombic system. It requires for solution about 6700 parts of cold or 2500 of boiling water; the solution is of decidedly alkaline reaction, and an intensely bitter taste which may be distinctly perceived though it contain no more than ¹/₆₀₀₀₀₀ of the alkaloid. The best solvents for strychnine are spirit of wine or chloroform; it is but very sparingly soluble in absolute alcohol, benzol, amylic alcohol, or ether. The alcoholic solution deviates the ray of polarized light to the left.
Strychnine is not restricted to the fruit of the plant under notice, but also occurs in the wood and bark.[1596] It is moreover found in the wood of the root of Strychnos colubrina L., and in the bark of the root of Strychnos Tieute Lesch., both species indigenous to the Indian Archipelago.
The discovery of Brucine was made in 1819 by the same chemists, in nux vomica bark, then supposed to be derived from Brucea ferruginea Héritier (B. antidysenterica Miller), an Abyssinian shrub of the order Simarubeæ. The presence of brucine in nux vomica and St. Ignatius’ Bean was pointed out by them in 1824. Brucine, dried over sulphuric acid, has the formula C₂₃H₂₆N₂O₄, but it crystallizes from its alcoholic solution with 4 OH₂. In bitterness and poisonous properties, as well as in rotatory power, it closely resembles strychnine, differing however in the following particulars:—it is soluble in about 150 parts of boiling water, melts without alteration a little above 130° C. In common with its salts, it acquires a dark red colour when moistened with concentrated nitric acid.
The proportion of strychnine in nux vomica appears to vary from ¼ to ½ per cent. That of brucine is variously stated to be 0·12 (Merck), 0·5 (Wittstein), 1·01 (Mayer) per cent.
A third crystallizable base, called Igasurine, was stated in 1853 by Desnoix to occur in the liquors from which strychnine and brucine had been precipitated by lime. Schützenberger’s investigations (1858) are far from proving the existence of “igasurine.”[1597]
In nux vomica, as well as in St. Ignatius’ Beans, the alkaloids, according to their discoverers, are combined with Strychnic or Igasuric Acid; Ludwig (1873), who prepared this body from the latter drug, describes it as a yellowish-brown amorphous mass, having a strongly acid reaction and a sour astringent taste, and striking a dark green with ferric salts. We have ascertained the correctness of Ludwig’s observations.
Nux vomica dried at 100° C. yielded us when burnt with soda-lime 1·822 per cent. of nitrogen, indicating about 11·3 per cent. of protein substances. By boiling ether, we removed from the seeds 4·14 per cent. of fat; Meyer[1598] found it to yield butyric, capronic, caprylic, caprinic and other acids of the series of the common fatty acids, and also one acid richer in carbon than stearic acid. Nux vomica also contains mucilage and sugar. The latter, which according to Rebling (1855) exists to the extent of 6 per cent., reduces cupric oxide without the aid of heat. When macerated in water, the seeds easily undergo lactic fermentation, not however attended with decomposition of the alkaloids. The stability of strychnine is remarkable, even after ten years of contact with putrescent animal substances.
Commerce—Large quantities of nux vomica are brought into the London market from British India.[1599] The export from Bombay in the year 1871-72 was 3341 cwt., all shipped to the United Kingdom.[1600] Madras in 1869-70 exported 4805 cwt.; and Calcutta in 1865-66, 2801 cwt. The quantity imported into the United Kingdom in 1870[1601] was 5534 cwt.
Nux vomica is stated by Garnier (l.c. page 429, note) to be largely exported from Cambodja to China.
Uses—Tincture and extract of nux vomica, and the alkaloid strychnine, are frequently administered as tonic remedies in a variety of disorders.