Ext. Glycyrrh. [Extract of Licorice]
"The commercial Extract of Glycyrrhiza." U. S.
Extractum Liquiritiae; Liquorice, Licorice; Extrait de Reglisse, Fr. Cod.; Sue de Reglisse, Sucre noir, Fr.; Succus Liquiritiae, P.G.; Lakriz, Lakritzensaft, Süssholzsaft, G.; Estratto di liquirizia, Sugo di liquirizia. It.; Extracto acuoso deregaliz, Regaliza en hallos, Sp.
Licorice is an article of export from the north of Spain, particularly Catalonia, where it is obtained in the following manner. The roots of the G. glabra, having been dug up, thoroughly cleansed, and half dried by exposure to the air, are cut into small pieces, and boiled in water until the liquor is saturated. The decoction is then allowed to rest, and, after the dregs have subsided, is decanted, and evaporated to the proper consistence. The extract, thus prepared, is formed into rolls from five to six inches long by an inch in diameter, which are dried in the air, and wrapped in laurel leaves.
The British Pharmacopoeia gives a process for making extract of licorice. The U. S. Pharmacopoeia directs that not less than 60 per cent. of it should be soluble in cold water.
Much licorice is prepared in Calabria, according to Fee, from the G. echinata, which abounds in that country. The process is essentially the same as that just described, but conducted with greater care, and the Italian licorice is purer and more valuable than the Spanish. It is in cylinders, generally somewhat smaller than the Spanish, and usually stamped with the manufacturer's brand. Most of the extract brought to this country comes from Messina and Catania in Sicily and Naples, from Seville and Saragossa in Spain, and from Smyrna in Turkey. Perhaps in no other part of the world is more licorice consumed than in the United States, from four to five thousand tons having been imported annually before 1860; but the article is now made on an extensive scale in this country, very successfully, with the best modern appliances, and of such good quality as to have almost driven the foreign article out of the market. The principal use of Extract of Licorice is in the manufacture of chewing tobacco, that in the form of rolls as sold by the druggists being a comparatively small portion of the whole amount consumed.
Crude Licorice, Licorice Paste, or Licorice Mass, as it is variously termed, is found in the market in cases ranging from two hundred and fifty to four hundred pounds, of a hard pilular consistence and, as its name implies, in a mass, which has been run into the case while hot and then allowed to cool.
Licorice is usually in cylindrical rolls, somewhat flattened, and often covered with bay-leaves. We have seen it abroad and in this market in large cubical masses. When good, it is black, dry, brittle, breaking with a shining fracture, of a peculiar sweet and slightly acrid or bitterish taste, and almost entirely soluble, when pure, in boiling water.
It is described officially as "in flattened cylindrical rolls or in masses, of a glossy black color externally; fracture brittle, sharp, smooth, conchoidal; taste characteristic and sweet. When pulverized it yields a brown powder. Not less than 60 per cent. of Extract of Glycyrrhiza is soluble in cold water. The yield of ash does not exceed 6 per cent." U. S. Neumann obtained 460 parts of aqueous extract from 480 parts of Spanish licorice. It is, however, considerably less soluble in cold water. It is often impure from accidental or fraudulent addition or careless preparation. Starch, sand, the juice of prunes, etc., are sometimes added, and carbonaceous matter, and even particles of copper, are found in it, the latter arising from the boilers in which the decoction is evaporated. In different commercial specimens examined by Chevallier he found from 9 to 50 per cent. of insoluble matter. (J. P. C., xxx, 429.) This is by no means, however, always impurity. In the preparation of the extract by decoction, a portion of matter originally insoluble, or rendered so by decoction, is taken up, and is, in fact, necessary to the proper constitution of the licorice. When this is prepared with cold water, or even with hot water by simple displacement, the extract attracts moisture from the air, becomes soft, and loses the characteristic brittleness of the drug. The additional substances taken up in decoction serve to protect the extract against this change. Delondre has obtained the same result by using steam as the solvent. He prepares from the root an excellent licorice, having all the requisite qualities of color, taste, and permanence, by passing steam, in suitable vessels, through the coarse powder of the root. The vapor thoroughly penetrates the powder, and is drawn off as it condenses. With about 500 lbs. of the root, this treatment is continued for twelve hours, and repeated at the end of five days. The liquors are collected, decanted, clarified with about 4 lbs. of gelatin, and quickly evaporated. After being put into the form of cylinders, the extract is kept for ten days in a drying room, at a temperature of 25° C. (77° F.). A bitter or empyreumatic taste is a sign of inferior quality in licorice. As ordinarily found in commerce, it requires to be purified. (See Extractum Glycyrrhizae Purum; also Glycyrrhizinum Ammoniatum.)
Licorice contains glycyrrhizin, C24H36O9, a glucoside, partly free and partly in combination with ammonia, to which combination the characteristic sweet taste of licorice is due. The glycyrrhizin when boiled with dilute acids decomposes into glycyrrhetin, C18H26O4, and a fermentable sugar.
According to Mellor (A. J. P., 1898, 23, 54, 136) the best process for estimating glycyrrhizin is as follows: The best menstruum with which to treat the commercial powdered extract is a mixture of 40 mils ammonia water, 240 mils of alcohol, and sufficient water to make a liter. After extraction, filter, and precipitate with diluted sulphuric acid. Of twelve samples examined, the highest was a Greek licorice with 27.78 per cent., and the lowest a Spanish with 5.28 per cent. of glycyrrhizin. Of insoluble matter, the highest was a Spanish with 36.52 per cent., and the lowest a Greek with 5.95 per cent. The average yield, however, was strongly in favor of American licorice. In determining the per cent. of glycyrrhizin in the commercial extract, the tobacco manufacturers dissolve 10 Gm. in 100 mils of water, add 200 mils of alcohol, and allow it to stand over night. The insoluble matter will then have mostly settled; the filtrate may be acidulated with sulphuric acid, and the precipitated glycyrrhizin dried and weighed. For an improvement on the foregoing method see Dwier's article in the Analyst for 1913, p. 367, translated from Ann. Falsif., 1913, p. 252; Also Evans' Sons, Lescher and Webb method. Proc. A. Ph. A., 1911, 57 from Chem. Ztg., 1911, No. 92.
The so called refined licorice, found in commerce in small cylindrical pieces not thicker than a pipestem, is prepared by dissolving the impure extract in water without boiling, straining the solution, and evaporating. The object of this process is to separate not only the insoluble impurities, but also the acrid oleoresinous substance which is extracted from the licorice root and is necessarily mixed with the unrefined extract. It is customary to add, during the process, a portion of sugar, gum, flour, starch, or perhaps glue. These additions, or something equivalent, are necessary to obviate the deliquescent property of the pure licorice. According to Delondre, 15 per cent. of gum is the proper proportion, when this substance is used; Geiseler has found sugar of milk to lessen the disposition of the extract to absorb moisture; but he considers the best addition, on the whole, to be very finely powdered licorice root, which should be used in the proportion of 1 part to 16 of the purified extract. (A. J. P., xxviii. 225.) The preparation is sometimes attacked by small worms, probably in consequence of the farinaceous additions. Excellent licorice is prepared in some parts of England, from the root cultivated in that country. The Pontefract cakes are small lozenges of licorice made in the vicinity of Pontefract, England. For methods of assaying extract of licorice, see A. J. P., 1896, 663; also 1898, 23, 136.
Uses.—Licorice has some demulcent property and is a popular addition to various lozenges. In large quantities it is somewhat laxative. Its most important role in medicine, however, is for the purpose of disguising the taste or covering the acrimony of various drugs such as quinine or ammonium chloride. It is also used to impart consistency to pills and troches.
Off. Prep.—Trochisci Ammonii Chloridi, U. S.; Trochisci Cubebae, U. S.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.