Jalapa. U. S., Br. Jalap.

Related entry: Scammony - Orizaba Jalap - Resin of Scammony - Pharbitis - Kaladana - Turpeth

"The dried tuberous root of Exogonium Purga (Wenderoth) Bentham (Fam. Convolvulaceae), yielding not less than 7 per cent. of the total resins of Jalap." U. S. "Jalap consists of the dried tubercules of Ipomoea Purga, Hayne." Br.

Radix Jalapae, Radix Ipomoearum; Jalap Tubereux ou officinal, Fr. Cod.; Tubera Jalapae, P. G.; Jalape, Jalapen-knollen, Jalapenwurzel, G.; Gialappa, Sciarappa, It.; Jalapa (Raiz de), Sp.

The precise botanical origin of jalap remained long unknown. It was at first ascribed by Linnaeus to a Mirabilis, and afterwards to a new species of Convolvulus, to which he gave the name of C. Jalapa. The correctness of the latter reference was generally admitted, and, as the Ipomoea macrorrhiza of Michaux, growing in Florida and Georgia, was believed to be identical with the C. Jalapa of Linnaeus, it was thought that this valuable drug, which had been obtained exclusively from Mexico, might be collected within the limits of the United States; but the error of this opinion was soon demonstrated. John R. Coxe, of Philadelphia, received living roots of jalap from Mexico in 1827, and succeeded in producing a perfect flowering plant, of which a description was published by Nuttall (Am. J. M. S., Jan., 1830). The same plant has since been cultivated in various parts of Europe, and has been introduced into the Neilgherry Hills of India, where it grows vigorously. J. H. Balfour (Curtis's Bot. Mag., Feb., 1847) maintains that the plant belongs to the genus Exogonium of Choisy, as defined in De Candolle's Prodromus, being distinguished from Ipomoea by its exserted stamens. Bentham and Hooker, however, do not acknowledge the validity of the various genera into which Ipomoea has been broken up by Choisy (Genera Plantarum, ii). Engler and Pranti have restored the genus Exogonium [E. Purga (Wender.) Benth.] for the plant yielding the root called jalap.

The root of Exogonium Purga (Ipomoea Purga Hayne) is a roundish, somewhat pear-shaped tuber, externally blackish, internally white, with long fibers proceeding from its lower part, as well as from the upper root-stalks. A tuber, produced by Coxe, was, in its third year, between two and three inches in diameter. The stem is round, smooth, much disposed to twist, and rises to a consider-able height upon neighboring objects, about. which it twines. The leaves are petiolate, heart-shaped, entire, smooth, pointed, deeply sinuated at the base and prominently veined on their under surface. The lower leaves are nearly hastate or with diverging angular points. The flowers, which are large and of a lilac-purple color, stand upon peduncles about as long as the petioles. Each peduncle supports two or, more rarely, three flowers. The calyx is without bracts, five-leaved, obtuse, with two of the divisions external. The corolla is funnel-form. The stamens are five in number, with oblong, white, somewhat exserted anthers. The stigma is simple and capitate.

The jalap plant is a native of Mexico, where it is dug during the whole year, and usually dried over the hearths of the Indian huts. It derives its name from the city of Jalapa, in the state of Vera Cruz, in the neighborhood of which it grows, at the height of about 6000 feet above the ocean. The drug is brought from the port of Vera Cruz in bags containing usually between 100 and 200 pounds. The amount of jalap annually invoiced through the Vera Cruz consulate to the United States is about 200,000 pounds. The jalap plant is now successfully cultivated in the government cinchona plantations in India. Analyses of the Indian tubers show that when grown on fresh soil they contain from 16 to 17 per cent. of resin, and that by manuring the percentage is notably increased, even to 22 per cent. It has also been cultivated in Jamaica, South America and Ceylon. The jalap grows freely in the south of England, but the season is too short for the production of seed by it, although the root has yielded 11.97 per cent. of resin. (P. J., Feb., 1869.) For an account of the cultivation of jalap in Madras, see Am. Drug., 1896,127.

Properties.—Jalap is officially described as follows:" Fusiform, irregularly ovoid or pyriform, upper end more or less rounded, lower end slightly tapering, the large roots often incised or cut into pieces; from 4 to 15 cm. in length and from 12 to 60 mm. in diameter; externally dark brown, longitudinally wrinkled or furrowed and with numerous lenticels; hard, compact, not fibrous; when broken, internally dark brown, mealy or waxy, bark from 1 to 2 mm. in thickness outer bundles separated from the outer cortical layer by a distinct, brown cambium zone; odor slight but distinctive, smoky; taste somewhat sweet and acrid. The powder is light brown; starch grains numerous, single or 2- to 3-compound, and more or less swollen, ellipsoidal or ovoid with concentric or excentral lamellae and radiating clefts or fissures, from 0.003 to 0.035 mm. in diameter; calcium oxalate in rosette aggregates from 0.01 to 0.035 mm. in diameter; tracheae short, wide, with simple or bordered pores; lactiferous vessels with' yellowish-brown, resinous masses. Jalap yields not more than 6.5 per cent. of ash." U. S.

"Tubercules dark brown, irregularly oblong, napiform or fusiform, three to eight centimetres or more long, the larger being often incised. Hard, compact and heavy; externally wrinkled, and marked with small transverse scars; internally yellowish-grey to dingy brown. In transverse section irregular, dark, concentric lines; examined microscopically numerous compound starch grains, many of which are gelatinised, cluster-crystals of calcium oxalate, and cells containing a resinous emulsion stained yellow by N/10 solution of iodine; in the wood, pitted vessels and tracheids. Characteristic odor; taste at first sweet but afterwards acrid and disagreeable. Ash not more than 6.5 per cent. Yields not less than 9 or more than 11 per cent. of resin having the properties of Jalap Resin, when treated by the process described under "Jalapae Resina."" Br.

Jalap is usually kept by pharmacists in the state of powder, which is of a yellowish-gray color, and when inhaled irritates the nostrils and throat, and provokes sneezing and coughing. Jalap yields its active properties partly to water, and completely to diluted alcohol.

"Assay.—Pack 10 Gm. of Jalap, in No. 60 powder, in a cylindrical percolator and extract it with alcohol until the percolate measures 100 mils. Transfer 20 mils of the percolate to a separator, add 20 mils of chloroform, mix the liquids, then add 20 mils of distilled water and shake the mixture thoroughly. When the liquids have completely separated, draw off the chloroform into a tared beaker, wash the contents of the separator by rotating with 5 mils of chloroform and draw it off into the beaker. Evaporate the chloroform solution on a water bath, add about 2 mils of alcohol, again evaporate, and then dry the residue to constant weight at 100° C. (212° F.). The weight will be the amount of total resins from 2 Gm. of Jalap." U.S.

Buchner and Herberger supposed that they had discovered a basic substance, which they called jalapin. G. A. Kayser found that the resin of jalap previously discovered by Cadet de Gassicourt consists of two portions, one of which, amounting to seven parts out of ten, is hard and insoluble in ether, the other is soft and soluble in that menstruum. The hard resin he named rhodeoretin, and found to be identical with the jalapin of Buchner and Herberger, By reaction with the alkalies it is converted into an acid, called rhodeoretinic acid. Rhodeoretin is slightly soluble in water, freely so in alcohol, and insoluble in ether, chloroform, or benzene. and the alcoholic solution is precipitated both by ether and water. It is dissolved by solutions of the alkalies, more quickly if heated, and is not precipitated by acids, having become soluble by conversion into the acid above referred to. It purges violently in the dose of three or four grains, and is supposed to be the active principle of jalap. Mayer confirmed and extended the observations of Kayser. He gave the name of convolvulin to Kayser's rhodeoretin, and stated its formula as C₃₁H₅₀O₁₆. This substance is colorless when pure, dissolving easily in ammonia water, and is not reprecipitated by acids, because of its conversion into convolvulinic acid, which is a hydroxide of the glucoside convolvulin. This, on being treated with nitric acid, yields sebacic acid. Convolvulin possesses in a high degree the purgative properties of jalap. A. Kromer (Ph. Z. R., 1894, Nos. 1-7) also made a study of convolvulin. He finds it to be laevo-gyrate, and gives it the formula C_H_O_, which was later changed (Die Glykoside, Van Rijn, 1900, p. 391) and is now given by Hoehnel as C₅₄H₉₆O₂₇, which is deduced from its analysis and decomposition products; alkalies decompose it into one molecule of volatile methylethyl-acetic acid, C₅H₁₀O₂, one molecule of purginic acid, C₂₅H₄₆O₁₂, and one molecule of convolvulinic acid, C₄₅H₈₀O₂₈. (See also A. Pharm., 1901, 373.) This latter is amorphous, yielding a white hygroscopic powder soluble in water and alcohol, insoluble in ether; strong sulphuric acid colors it red or brown-red; by the action of acids one molecule of convolvulinic acid yields five molecules of a glucose and one molecule of convolvulinolic acid, C₁₅H₃₀O₃, which is insoluble in water, melts at 51.5° C. (124.7° F.),is not colored by sulphuric acid, and is isomeric with jalapinolic acid and scammonolic acid, both of which melt at from 63° to 64° C. (145.4°-147.2° F.). Mayer obtained from Ipomoea orizabensis a resin which he called jalapin, which was afterwards shown by Keller to be identical with the resin of scammony. Mayer's jalapin differs from convolvulin in being soluble in ether. The formula of jalapin, according to Samuelson, is C₃₄H₅₆O₁₆. Poleck (A. J. P., 1892, p. 465) continued the investigation of the jalapin from I. orizabensis, and confirmed the identity of it with scammonin, giving it the formula C₃₄H₅₆O₁₆. He suggested that the name of jalapin, which is misleading, should be replaced by orizabin. A. F. Stevenson (N. R., 1879, 359) has studied the two resins found in jalap, and furnishes a tabular statement of the differences between the soft resin jalapin and the hard resin convolvulin, which is given in the following table. For the method of obtaining the resin of jalap pure, see Resina Jalapae.

Power and Rogerson report a chemical examination of Ipomoea purpurea Roth, known as the common morning glory. They conclude that this plant, like many other species of the same genus, contains resins which possess purgative properties, and is thus capable of being used medicinally. (A. J. P., 1908, p. 255.)

Jalap is apt to be attacked by worms, which, however, are said to devour the amylaceous or softer parts, and to leave the resin, so that the worm eaten drug is more powerfully purgative than that which is sound. Thus, out of 397 parts of the former, Henry obtained 72 parts of resin, while from an equal quantity of the latter he procured only 48 parts. Hence, worm eaten jalap should be employed for obtaining the resin, but should not be pulverized, as it would afford a powder of more than the proper strength. The drug is also liable to various adulterations, or fraudulent substitutions, which, however, can usually be detected without difficulty by means of the microscope.

According to Herlant, even in powder it is easy to detect the presence of the root of Mirabilis Jalapa, which is sometimes used as an adulterant to jalap, by the presence of raphides of calcium oxalate.

Tampico Jalap (Purga de Sierra Gorda, Mexican).—This drug closely resembles in appearance, odor, and taste the true jalap, but the tubers are somewhat smaller, more elongated and shrivelled. According to Ambrose Andouard, it is the jalap digite majeur of Guibourt. Through the efforts of Daniel Hanbury, of London, aided by two Prussian officials in Mexico, Hugo Finck, vice-consul at Cordova, and E. Bonecke, consul-general at Mexico, the origin of the drug was traced to the state of Guanajuato, where it grows along the Sierra Gorda, near San Luis de la Paz. In this place it is purchased from the Indians, and conveyed by mules to Tampico, where it enters into commerce. Through the agency of the same gentlemen, Hanbury, after some failures, succeeded in obtaining a living tuber, from which he raised a flourishing plant that proved to be an undescribed species of the genus Ipomoea, differing from I. Purga by its bell-shaped corolla and pendulous flower-buds. To it Hanbury gave the name I. simulans. (A. J. P., July, 1870.) H. Spirgatis, of Konigsberg, obtained a resin by preparing a tincture of the Tampico jalap, evaporating, washing, boiling the residue in water, redissolving in alcohol, and decolorizing by charcoal. He gave it the name of tampicin. Its physical properties are similar to those of the jalap resin. It is brittle, tasteless, inodorous, insoluble in water, soluble in ether and alcohol, and in solution has a feeble acid reaction. By strong alkalies it is changed into a soluble acid which Spirgatis calls tampicic acid. By the action of diluted sulphuric, nitric, or hydrochloric acid, it is converted, slowly if cold, but rapidly with heat, into a peculiar acid called tampicolic, with sugar. For the mode of preparing these acids, and their properties, the reader is referred to an article in N. R., July, 1871, p. 50. The melting point of tampicin is 130° C. (266° F.); its formula is C₃₄H₅₄O₁₄. The percentage of it yielded by the drug varies from a minimum of 10 per cent. (Hanbury) to a maximum of 15 per cent. (Umney). Andouard states that it is purgative.

The average percentage of resin in Jalap has of late years distinctly lessened; indeed this fact has received official recognition. The U. S. P., 1890, required 12 per cent., and the French Codex, 1884, 16 to 18 per cent. Much of the commercial jalap is far below the lowered official standard, and this appears to be due, not, as believed by Fluckiger, to the extraction of the resin from the roots in Mexico, but to the fact that the wild tubers are collected indiscriminately from November to March; the cultivators of India are very careless in their methods. The lowness of the U. S. P. standard (7 per cent.) is to be regretted, especially as the Br. Ph. requires 11 per cent., but it is probably necessary, practically, to meet the commercial conditions. The German Pharmacopoeia of 1900, however, requires 9 per cent. From a compilation by M. I. Wilbert (J. A. Ph. A., 1914, 1286) the range of 173 reported analyses of jalap was from 3.67 per cent. to 21.76 per cent. (For various analyses of commercial Jalap, see U. S. D., 18th ed., also J. P., lxxii, p. 152.)

A comparison of various methods of assay was made by Dr. P. Seidler (Ph. Ztg., 1912, No. 2, 15), who recommends the process of the P. G-.V., which he says can be still further improved.

The question as to possible substitutes for the official species is also growing in importance. Fluckiger pointed out that the seeds of the Ipomoea hederacea (see Kaladana) yield 8 per cent. of resin identical with that obtained from Ipomoea Purga, and the British Pharmacopoeia now recognizes Kaladana and its resin. Shimoyama, of Tokio, has shown that jalap resin can be obtained from the Ipomoea triloba (Pharbitis triloba) of Japan. M. K. Hyrano confirms this, and states that the seeds of the plant have long been used in Japan, under the name of "kengashi" (For details and method of extracting the resin, see P. J., Oct., 1888.)

Jalap should be rejected when it is light, of a whitish color internally, of a dull fracture, spongy, or friable. Powders of calomel and jalap, taken on long voyages to southern climates, are said, when brought back, to have become consolidated, and so far chemically altered as plainly to exhibit globules of mercury. This change is ascribed by Schacht and Wackenroder to a fungous growth. (A. Pharm., xxxix, 239.)

Uses.—Jalap is an active cathartic, operating briskly and sometimes painfully upon the bowels, and producing copious watery stools. The aqueous extract purges moderately, without much griping, and is said to increase the flow of urine. The portion not taken up by water gripes severely. The aqueous extract obtained from jalap, previously exhausted by rectified spirit, is said to have no cathartic effect. Jalap was introduced into Europe in the latter part of the sixteenth or the beginning of the seventeenth century, and at one time ranked among the purgative medicines most extensively employed. It is applicable to most cases in which an active cathartic is required, and from its hydragogue powers is especially adapted to the treatment of dropsy. It is generally given in connection with other medicines, which assist or qualify its operation. In dropsical complaints it is usually combined with potassium bitartrate.

The combination of jalap with calomel has long been popular, in the United States, in bilious fever and other complaints attended with congestion of the liver or portal circle. In overdoses jalap may produce dangerous hypercatharsis. It is said to purge when applied to a wound. Jalapin when taken internally is probably absorbed, but as yet its presence has never been detected in the urine, and it remains uncertain whether it is eliminated or destroyed. Muller (In. Dis., Dorpat, 1885) found traces of it in the blood, and even in the heart, lungs, and spleen of cats poisoned with it.

The dose of jalap, in powder, is from ten to twenty grains (0.65-1.3 G-m.).

Off. Prep.—Pulvis Jalapae Compositus, U. S., Br.; Pulvis Scammonii Compositus, Br.; Resina Jalapae, U. S. (Br.); Tinctura Jalapae, Br., N. F.; Tinctura Jalapae Composita, Br., N. F.; Extractum Jalapae, N. F.; Fluidextractum Jalapae, N. F.; Pilulae ad Prandium (Cole's), N. F.; Pilulae Catharticae Vegetabiles (from Resin), N. F.; Pulvis Hydrargyri Chloridi Mitis et Jalapae, N. F.; Syrupus Sennae Aromaticus, N. F.

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.