Glycyrrh. (Licorice Root, Licorice, Liquorice Root]
"The dried rhizome and roots of Glycyrrhiza glabra typica Regel et Herder, known in commerce as Spanish Licorice, or of Glycyrrhiza glabra glandulifera Regel et Herder, known in commerce as Russian Licorice (Fam. Leguminosae). Preserve powdered and whole Glycyrrhiza in tightly-closed containers to which a few drops of chloroform or carbon tetrachloride are added from time to time to prevent attack by insects." U S. "Liquorice Root is the peeled root and peeled subterranean stem of Glycyrrhiza glabra, Linn., and other species of Glycyrrhiza." Br.
Glycyrrhizae Radix, Br.; Radix Glycyrrhiza Hispanicae. Spanish Licorice Root; Reglisse, Fr. Cod.; Racine de Reglisse, Bois doux, Racine douce, Bois de Reglisse, Fr.; Radix Liquiritiae, P. G.; Spanisches Süssholz, Spanische Süssholzwurzel, Süssholzwurzel, G.: Liquirizia, It.: Regalia (Raiz de), Orozus, Palo dulce, Sp.
Glycyrrhiza glabra has a perennial root, which is round, succulent, tough, and pliable, furnished with sparse fibers, rapid in its growth, and in a sandy soil penetrates deeply into the ground. The stems are herbaceous, erect, slightly branching, and usually four or five feet in height. The leaves are alternate, pinnate, consisting of several pairs of ovate, blunt, petiolate leaflets, with a single leaflet at the end, of a pale-green color, and clammy on their under surface. The flowers are violet or purple, formed like those of the pea, and arranged in axillary spikes supported on long peduncles. The calyx is tubular and persistent. The fruit is a compressed, smooth, acute, one-celled legume, containing from one to six small kidney-shaped seeds. There are two very distinct varieties of the plant yielding the root: in the typical form, or var. typica, the underground portion is spreading, producing slender rhizomes. This plant grows best on sandy soil near streams, usually not being found more than fifty meters from a body of water. It is indigenous to southern Europe and southwestern Asia, and is cultivated in England, Germany and Austria and has been grown on an experimental scale in the United States. The second variety, var. glandulifera, has been sometimes designated as a distinct species, because the entire plant is pubescent or roughly glandular. The underground portions are not spreading and it produces a large fusiform root. This variety is indigenous to southeastern Europe and in western Asia. It is also cultivated to some extent in Russia. Asiatic licorice, known as "Chuntschir," is obtained from G. uralensis Fisch. The plant is found in Siberia, Turkestan and Mongolia, and it is claimed that the root is of better quality and is but little inferior to the best Russian licorice. (Pharm. Journ. Russ., 1908, p. 1063; also P. J., 1908, lxxxi, 164.)
It is probable that a portion of the root from Italy and Sicily is the product of G. echinata, which grows wild in Apulia. This species is also abundant in the south of Russia, where, according to Hayne, sufficient extract is prepared from it to supply the whole Russian empire. Large quantities of licorice root are now imported for the purpose of making the extract. The annual imports of licorice root in the United States is enormous. Between 75,000,000 and 100,000,000 pounds are annually imported from Turkey and about half of this quantity from Russia. The U. S. Department of Agriculture has had Spanish licorice under cultivation in South Carolina and the plant thrives in various localities in this country. It is said that the soil and climatic conditions in the Coachella Valley of California are ideal for the growing of the licorice plant. Ozmun describes the plantation of licorice in Turkey and the Levant and the manner of harvesting and handling this article. The licorice plant has been cultivated according to precedence of date in Spain, Italy, Greece, The Ottoman Empire, Russia, China, Turkestan and Persia. (See Proc. A. Ph. A., 1905, p. 273, A. J. P., 1907, p. 39; Oil, Paint and Drug Sep., 1906, p. 37, and 1908, p. 22.)
A species of Glycyrrhiza, G. lepidota Pursh., grows abundantly about St. Louis, in the State of Missouri, and flourishes from Colorado to New Mexico, westward into Nevada and Northern California and northward to Washington. It is probably the same as the licorice plant mentioned by Mackenzie as growing on the northern coast of this continent. Nuttall states that its root possesses in no inconsiderable degree the taste of licorice, and M. L. McCullough found it to contain 6.39 per cent. of crude glycyrrhizin, in contrast with 7.18 per cent. in the official species. (A. J. P., 1890.) Schneider reports that G. lepidota glutinosa Pursh., a native of California, is much like G. glabra and can no doubt be substituted for the true licorice. (Pacific Pharm., II, p. 144.)
Properties.—The two varieties are described in the U. S. Pharmacopoeia as follows:
"Spanish Licorice (also known as Italian, Levant, Persia, Turkish, or Arabian Licorice)—Nearly cylindrical, upper portion more or less knotty; usually in pieces from 14 to 20 cm. or more in length and from 5 to 20 mm. in thickness, externally yellowish-brown or dark brown, longitudinally wrinkled, the thinner rhizomes often having prominent alternate buds, the thicker rhizomes having distinct corky patches; fracture coarsely fibrous; internally lemon-yellow, radiate; bark from 1 to 3 mm. in thickness; wood porous, in narrow wedges, rhizome with small pith; odor distinctive; taste sweetish and slightly acrid. Under the microscope, transverse sections of pieces of the older rhizome of Spanish Licorice show a periderm of numerous layers of yellowish-brown cork cells, a phellogen and one or more rows of cells of the phelloderm, the cells showing a tendency to collenchymatous thickenings and with occasional monoclinic prisms of calcium oxalate; a middle bark of starch-bearing parenchyma and whitish groups of bast-fibers surrounded with crystal-fibers; inner bark with a very characteristic radial arrangement of phloem and medullary rays, the phloem consisting of wedges of small groups of bast-fibers and parenchyma, separated by an almost continuous, obliterated sieve tissue, the cells of the latter being very irregular in outline and with thick, highly refracting walls; medullary rays from 1 to 8 cells wide; wood characterized by broad wedges consisting of large tracheae with yellowish walls, small compact groups of wood-fibers and starch-bearing parenchyma alternating with the broad medullary rays; pith composed of parenchyma, the cells being large, more or less polygonal in outline and containing numerous starch grains, or prisms of calcium oxalate. In sections of roots the pith is absent.
"Russian Licorice.—Nearly cylindrical, somewhat tapering, sometimes split longitudinally, from 15 to 30 cm. in length and from 1 to 5 cm. in diameter; when deprived of the outer corky layer, it is externally pale-yellow; fracture coarsely fibrous; internally lemon-yellow; wood radially cleft; odor distinct; taste sweetish. Under the microscope, transverse sections of the rhizome and roots of Russian Licorice somewhat resemble those of Spanish Licorice, but the cork cells are absent.
Powdered Glycyrrhiza is pale brownish-yellow (Spanish Licorice) or pale yellow (Russian Licorice); starch grains numerous, mostly single and elliptical or oval, and from 0.002 to 0.02 mm. in diameter; tracheae mostly with bordered pores; wood- and bast-fibers numerous, strongly lignified, very long, much attenuated at the ends and about 0.01 mm. in width; crystal-fibers with monoclinic prisms of calcium oxalate, the latter from 0.01 to 0.02 mm. in diameter, occasional fragments of reddish-brown cork cells occur in Spanish Licorice, but are practically absent in the Russian Licorice. Add 10 Gm. of powdered Glycyrrhiza to 100 mils of distilled water, allow the mixture to macerate for fifteen minutes with occasional stirring; and then heat it for one-half hour on a water bath. Filter the mixture and add through the filter enough water to make the filtrate measure 100 mils; not less than 0.2 Gm. of residue remains on evaporating 10 mils of this filtrate and drying it at 100° C. (212° F.). Glycyrrhiza yields not more than 7 per cent. of ash." U. S.
"When 5 grammes are macerated with 50 millilitres of chloroform water for twenty-four hours, shaken occasionally and filtered, 10 millilitres of the filtrate evaporated in a flat-bottomed dish yield not less than 0.200 gramme of residue dried at 100° C. (212° F.). Ash not more than 6 per cent." Br.
Formerly commerce was chiefly supplied with licorice root by Italy and Spain, but the amount coming from these sources is at present probably not more than 10 per cent. of the whole, the greater portion coming from Southern Russia, a large amount from Anatolia and Syria, and a little from Turkey and Persia. The Spanish variety has been most esteemed, but, according to H. N. Rittenhouse, the peeled Russian licorice is richer in glycyrrhizin and extractives than is any other variety, and is in fact the most valuable. Russian licorice is usually very large, quite sweet, but at the same time rather more bitter and acrid than is the Spanish variety. Licorice root is often worm eaten and more or less decayed; such root should be rejected, as should also the small fibrous roots often shipped from Spain. The best pieces are large, bright yellow internally, and have the layers and the bark distinct. Rusby has stated that he has seen ground licorice imported which apparently consisted of the peelings of Russian licorice. (Ph. Era, 1909, p. 634.)
A character said by Rothrock (A. J. P., 1884) to be diagnostic is the occurrence of crystal fibers adjoining the wood and bast fibers. These are recognized in the official description of the powdered drug. In the Russian root the parenchymatous wood-cells are larger than in the Spanish. The powder is of a grayish-yellow color, when the root is pulverized without being deprived of its epidermis; of a pale sulphur-yellow, when the epidermis has been removed. Bobiquet found the following ingredients in licorice root: (1) a peculiar transparent yellow substance, called glycyrrhizin, of a sweet taste, scarcely soluble in cold water, very soluble in boiling water, with which it gelatinizes on cooling, thrown down from its aqueous solution by acids, readily soluble in cold alcohol, insusceptible of the vinous fermentation, yielding no oxalic acid by the action of nitric acid, and therefore wholly distinct from sugar; (2) a crystallizable principle named agedo'ite by Robiquet, but subsequently proved to be identical with asparagin; (3) starch; (4) albumen; (5) a brown acrid resin; (6) a brown nitrogenous extractive matter; (7) lignin; (8) salts of calcium and magnesium, with phosphoric, sulphuric, and malic acids. Flückiger states that a small amount of tannin is also always contained in the root, or rather its bark. The chief constituent, glycyrrhizin, C44H63NO18, Gorup-Besanez (Ann. Ch. Ph., 118) considered to be a glucoside, as on boiling with diluted acids it breaks up into glycyrrhetin and an uncrystallizable sugar capable of fermentation. Roussin (J. P. C., July, 1875) found that the sweet taste of the root was not owing to the free glucoside, but to its compound with ammonia.
Habermann (Ann. Ch. Ph., 197) found that glycyrrhizin-ammonia was the acid ammonium salt of glycyrrhizic acid, a nitrogenous acid, and gave the formula C44H62NO18.NH4 for it. He succeeded in extracting from the commercial "ammoniacal glycyrrhizin," glycyrrhizic acid, which may be considered to be the active constituent of licorice. It was obtained by dissolving the crude glycyrrhizin in glacial acetic acid at a boiling temperature, rapidly filtering, again treating the crystalline parts of the filtrate in the same manner, and finally purifying by repeated crystallizations from 90 per cent. alcohol. Its properties are peculiar, and account to a great extent for the singular behavior of liquid licorice preparations. With water, in which the substance is but little soluble at ordinary temperature, it forms a transparent, faintly yellow jelly. On mixing 1 Gm. of the body with 100 mils of water, the mixture after a few hours becomes so jelly-like that the open vessel may be inverted without losing any substance. It is insoluble in ether, but slightly soluble in absolute alcohol (even boiling), more so in alcohol of 90 per cent., and especially so when hot. Its solubility increases with the decrease of the percentage of alcohol. The apparent glucosidal character of glycyrrhizic acid Habermann explains by the fact that it breaks up on boiling with diluted sulphuric acid into glycyrrhetin and parasaccharic acid, according to the reaction: C44H63NO18+2H2O = C32H47NO4 + 2C6H10O8.
(Ann. Ch. Ph., cxcvii; N. R., Sept., 1879.) By fusing glycyrrhizin with potassium hydroxide, Weselsky and Benedikt (Ber. d. Chem. Ges., 1876) obtained paraoxybenzoic acid.
For methods of quantitatively determining glycyrrhizin, see Ext. Glycyrrh., p. 452.
Uses.—Powdered licorice root is used for various pharmaceutical purposes as in the preparation of pills, either to give due consistence or to cover their surface and prevent them from cohering, and as a diluent of powdered extracts, etc. As a remedial agent it has been almost entirely replaced by the extract.
Off. Prep.—Extractum Glycyrrhizae, U. S., Br.; Extractum Glycyrrhizae Purum, U. S.; Fluidextractum Glycyrrhizae, U. S. (Br.); Mistura Glycyrrhizae Compositus (from Extract), U. S.; Pulvis Glycyrrhizae Compositus, U. S., Br.; Elixir Glycyrrhizae Aquosum (from Fluidextract), N. F.; Elixir Glycyrrhizae Aromaticum (from Fluidextract), N. F.; Fluidglyceratum Glycyrrhizae, N. F.; Mistura Ammonii Chloridi (from Pure Extract), N. F.; Syrupus Glycyrrhizae (from Fluidglycerate), N. F.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.