Another constituent of cubebs is Cubebin, crystals of which may sometimes be seen in the pericarp even with a common lens. It was discovered by Soubeiran and Capitaine in 1839; it is an inodorous substance, crystallizing in small needles or scales, melting at 125°, having a bitter taste in alcoholic solution; it dissolves freely in boiling alcohol, but is mostly deposited upon cooling; it requires 30 parts of cold ether for solution, and is also abundantly soluble in chloroform. We found this solution to be slightly lævogyre; it turns red on addition of concentrated sulphuric acid. If the solution of cubebin in chloroform is shaken with dry pentoxide of phosphorus, it turns blue and gradually becomes red by the influence of moisture. Cubebin is nearly insoluble in cold, but slightly soluble in hot water. Bernatzik (1866) obtained from cubebs 0·40 per cent. of cubebin, Schmidt (1870) 2·5 per cent. The crystals, which are deposited in an alcoholic or ethereal extract of cubebs, consist of cubebin in an impure state. Cubebin is devoid of any remarkable therapeutic action. Its composition, according to Weidel (1877) answers to the formula C₁₀H₁₀O₃; by melting it with caustic potash, cubebin is resolved as follows:—
| C₁₀H₁₀O₃ · 5 O = | CO₂ | · C₂H₄O₂ · | C₆H₃(OH)₂COOH. |
| Acetic Acid. | Protocatechuic Acid. |
The resin extracted from cubebs consists of an indifferent portion, nearly 3 per cent., and of Cubebic Acid, amounting to about 1 per cent. of the drug. Both are amorphous, and so, according to Schmidt, are the salts of cubebic acid. Bernatzik however, found some of them, as that of barium, to be crystallizable. Schulze (1873) prepared cubebic acid from the crystallized sodium-salt, but was unable to get it other than amorphous. The resins, the indifferent as well as the acid, possess the therapeutic properties of the drug.
Schmidt further pointed out the presence in cubebs, of gum (8 per cent.), fatty oil, and malates of magnesium and calcium.
Commerce—Cubebs were imported into Singapore in 1872 to the extent of 3062 cwt., of which amount 2348 cwt. were entered as from Netherlands India. The drug was re-shipped during the same year to the amount of 2766 cwt., the quantity exported to the United Kingdom being 1180 cwt., to the United States of America 1244 cwt., and to British India 104 cwt.[2199] In the previous year, a larger quantity was shipped to India than to Great Britain.
Uses—Cubebs are much employed in the treatment of gonorrhœa. The drug is usually administered in powder; less frequently in the form of ethereal or alcoholic extract, or essential oil.
Bernatzik and Schmidt, whose chemical and therapeutical experiments have thrown much light on the subject, have shown that the efficacy of cubebs being dependent on the indifferent resin and cubebic acid, preparations which contain the utmost amount of these bodies and exclude other constituents of the drug, are to be preferred. They would reject the essential oil, as they find its administration devoid of therapeutic effects.
The preparations which consequently are to be recommended, are the berries deprived of their essential oil and constituents soluble in water, and then dried and powdered; an alcoholic extract prepared from the same, or the purified resins.
Adulteration—Cubebs are not much subject to adulteration, though it is by no means rare that the imported drug contains an undue proportion of the inert stalks (rachis)[2200] that require to be picked out before the berries are ground. Dealers judge of cubebs by the oiliness and strong characteristic smell of the berries when crushed. Those which have a large proportion of the pale, smooth, ripe berries, which look dry when broken, are to be avoided.
We have occasionally found in the commercial drug a small, smooth two-celled fruit, of the size, shape, and colour of cubebs, but wanting the long pedicel. A slight examination suffices to recognize it as not being cubebs. We have also met with some cubebs of larger size than the ordinary sort, much shrivelled, with a stouter and flattened pedicel, one and a half times to twice as long as the berry. The drug has an agreeable odour different from that of common cubebs, and a very bitter taste. From a comparison with herbarium specimens, we judge that it may possibly be derived from Piper crassipes Korthals (Cubeba crassipes Miq.), a Sumatran species.