"The tuberous root of Ipomoea jalapa, Nuttall"—(U. S. P.); (Ipomoea purga, Hayne; Ipomoea Schiedeana, Zuccarini; Exogonium jalapa, Baillon; Exogonium purga, Bentham; Convolvulus jalapa, Linné; Convolvulus purga, Wenderoth).
ILLUSTRATIONS: Bentley and Trimen, Med. Plants, 186; Bot. Magazine, Vol. 73, Plate 4280.
Botanical Source.—Jalap has a fleshy, tuberous, pyriform root, with numerous roundish tubercles. The stems are several, smooth, brownish, very slightly rough, with a tendency to twist, twining about surrounding bodies. The leaves are long petioled, the first hastate, the succeeding ones cordate, acuminate, mucronate, smooth, deeply incised at base, and conspicuously veined beneath. Peduncles axillary, 2-flowered, rarely 3, twisted, as long as the petioles. Calyx has no bracts; composed of 5 smooth, obtuse, mucronate sepals. The corolla is funnel-shaped, purple, with a long, somewhat clavate tube, and an undulated limb, with 5 plaits. Stamens 5; filaments smooth, unequal, and longer than the corolla tube; anthers white, oblong-linear, and projecting. Ovary slender, and 2-celled; stigma simple, capitate, and deeply furrowed. Capsule 2-celled; cells 2-seeded; seeds unknown.
History.—It is only within comparatively recent years that any certainty has existed in relation to the plant from which jalap root is obtained. It was first spoken of in 1609, as Bryonia mechoacana nigricans, then it was regarded by Ray as Convolvulus Americanus jalapium dictus, after which Tournefort, being deceived by persons who asserted that they had seen the plant growing, referred it to a species of Mirabilis. Balfour placed it as the Exogonium purga, and Linnaeus named it Convolvulus jalapa, and thus much difference of opinion existed until, in 1827, when Dr. J. R. Coxe, of Philadelphia, succeeded in obtaining perfect flowers from roots of the true plant furnished to him from their native soils, and thus first made its true character known to the scientific world. The name of Ipomoea purga was bestowed upon the plant by Wenderoth and Hayne, but as the authorities of this country have, undoubtedly, the first claim, it may be viewed as fixed that I. jalapa, the name originally given to it by Nuttall, is the official plant.
The jalap plant is found in a deep, rich, vegetable soil, at an elevation of nearly 6000 feet above the level of the sea, growing in Mexico, near Chicanquiaco and Xalapa, from which last named place it is usually exported, and from which it has also obtained its name. It is generally imported in bags, containing 100 or 200 pounds. The root is the official part, and is gathered in all seasons, but principally in March and April, when the young shoots are appearing. The plant may be cultivated in the southern parts of the United States. In 1866, Dr. D. Hanbury planted a root or tuber of Jalap in a garden, near London, and obtained promising results. It is now successfully grown in Jamaica and in India, especially in the Nilgherry hills of that country. According to Warden (1887), the jalap tubers of India are not of first quality. Jalap is a very variable drug, much of it being of an inferior quality. The best kind is that known as the Vera Cruz variety. Several related, and often inferior drugs, e. g., Tampico jalap, have appeared on the market (see Related Species).
Description.—When fresh, the root is black externally, white and milky within, and varies in size according to its age, from that of a walnut to that of a moderate-sized turnip. It is dried in net bags over the fire, sometimes entire, and sometimes in sections. It is often preyed upon by insects which, however, leave its active part untouched, rendering it consequently more energetic. Jalap thus preyed upon is used for procuring the resin, but should not be given internally, except in much smaller doses than for the ordinary root. Jalap is rather difficult to pulverize, but if triturated with cream of tartar, sugar of milk, or other hard salt, the process of pulverization is facilitated, and the powder rendered much finer. When in powder, the color is a pale grayish-brown, and when in contact with the mucous membrane of the air-tube, causes coughing and sternutation, with an increased discharge of saliva. Its solvents are water, alcohol, or spirits. Water takes up a small portion of its cathartic principle, but considerable of an amylaceous and mucilaginous extractive matter. Alcohol dissolves the resin, on which its cathartic virtues depend. Ether only partially dissolves it. Diluted alcohol completely extracts its active properties.
The U. S. P. thus describes good jalap, and gives the method of valuation of same: "Napiform, pyriform, or oblong, varying in size, the large roots incised, more or less wrinkled, dark-brown, with lighter-colored spots, and short, transverse ridges; hard, compact, internally pale, grayish-brown, with numerous concentric circles composed of small resin cells; fracture resinous, not fibrous; odor slight, but peculiar, smoky, and sweetish; taste sweetish and acrid. On exhausting 100 parts of jalap with alcohol, concentrating the tincture to 40 parts, and pouring it into water, a precipitate of resin should be obtained, which, when washed with water, and dried, should weigh not less than 12 parts, and of which not over 10 per cent should be soluble in ether"—(U. S. P.).
Jalap root is seldom adulterated; if light, whitish internally, spongy, friable, and of a dull fracture, it should be rejected. The resin of jalap, met with in commerce, however, is subject to falsification, being adulterated sometimes with guaiac, colophony, and various inert substances. In the case of colophony, freshly rectified oil of turpentine will dissolve out this adulteration, while jalap resin is insoluble in this medium (Tromsdorff).
Chemical Composition.—Analysis of commercial jalap shows the presence of starch, uncrystallizable sugar (19 per cent, Guibourt), gum, coloring matter, a resin, soluble in alcohol, and a soft resin, soluble in ether. From 12 to 18 per cent is the average yield of resin (Pharmacographia), though as high as 22 per cent has been obtained. As stated above, the U. S. P demands 12 per cent of total resin, including not more than 1.2 per cent of ether-soluble resin. The resin of jalap may be obtained by treating the coarsely-chopped roots with water, which removes such constituents as sugar, gum, and coloring matter, and extracting the resin from the roots by means of boiling alcohol, specific gravity 0.880. This resin consists of two distinct resins. One of these, having the odor and acrid taste of jalap, is soft, of acid reaction, and soluble in ether as well as in alkaline solutions; from the latter it is reprecipitated by acids. Prof. Maisch (Amer. Jour. Pharm., 1887, p. 326) considers it a mixture of resins, not deserving a special name until better investigated. The other resin, insoluble in ether, is the purging principle (jalapurgin, Maisch, 1887; convolvulin, C31H50O16, Wm. Mayer, 1856; or C61H108O27, A. Kromer, 1894; rhodeoretin, of G. A. Kayser, 1844; and jalapin, of Buchner and Herberger, 1831). It is hard, white, odorless, and tasteless, while in alcoholic solution it is nauseously acrid. The latter solution is optically laevo-rotatory. Convolvulin (as it is mostly called) is insoluble, or nearly so, in water, ether, chloroform, carbon disulphide, petroleum benzin, oil of turpentine, etc., but dissolves readily in alcohol, acetic acid, acetic ether, in cold nitric acid, And in alkalies; in the case of ammonia being used, the heat of the water-bath effects solution. Upon again acidulating the alkaline solution, no precipitate is formed, owing to the conversion of convolvulin into convolvulic (convolvulinic) acid (C62H106O35, Mayer), an amorphous, white, hygroscopic powder, soluble in water and alcohol, and insoluble in ether. Of this substance convolvulin is the anhydride. Convolvulin, as well as convolvulic acid, are glucosids (Kayser). When convolvulic acid (C28H52O14, A. Kromer, Amer. Jour. Pharm., 1894, p. 197) is treated with the ferment emulsin, or with warm diluted acids, it is decomposed into 2 molecules of sugar (C6H12O6), and crystallizable convolvulinolic acid (C16H30O3, Kromer). The latter is insoluble in water and melts at 46° C. (114.8° F.). Convolulin, treated with the same agents, decomposes into glucose, volatile methyl-ethyl-acetic acid, and convolvulinolic acid; with alkalies, 1 molecule of methyl-ethyl-acetic and 2 molecules of convolvulinic acids are formed. Höhnel (1896), by the same agents, obtained 2 glucosid acids, convolvulinic and purginic acids (see Jahresb. der Pharm., 1896, p. 511). Strong nitric acid oxidizes convolvulin to carbonic and oxalic acids, and a small quantity of sebacic (ipomic) acid (C8H16[COOH]2), a substance which is also one of the products of the dry distillation of oleic fats.
Action, Medical Uses, and Dosage.—Jalap is an irritant and cathartic, operating energetically, occasioning profuse liquid stools with griping, and sometimes sickness at stomach, or even vomiting. Large doses produce violent hypercatharsis, sometimes terminating fatally. When applied to a wound, it is said to induce purgation. Notwithstanding its activity, it is a safe and convenient purgative, much in use among the profession, and is useful in all cases where it is desirable to produce an energetic influence on the bowels, or to obtain large evacuations. In intestinal inflammations it should not be used. United with the bitartrate of potassium, its hydragogue properties are much increased, and thus it proves beneficial in dropsies, as well as in some forms of scrofula. Jalap, however, is suitable for excitable, active conditions, and may be used where a cooling effect is desired, as when it is necessary to evacuate the bowels in febrile disorders. Inflammatory conditions of the biliary apparatus are exceptions to the rule that it should not be used in gastro-intestinal inflammations. When the rectum is impacted with a hard, fecal mass, the expulsion of the latter is facilitated by the purgative action of jalap, which greatly augments the intestinal secretions; all cases of constipation, due to dryness of the mucous membranes, through inactivity of the intestinal glands, are relieved by jalap. The dose for this latter purpose may be 5 grains in the morning, repeated for several days. When a stimulating laxative can not be used in hemorrhoids, jalap may be employed, and it is likewise efficient as a derivative in cerebral disorders. The antibilious physic (which see), or the following modifications (Locke) of it are very useful preparations: (1) Rx Powdered jalap, ℥viii; powdered senna, ℥xvi; powdered ginger, ℥i. Mix. Dose, a full teaspoonful in sweetened water; (2) Rx Jalap, ℥iij; potassium bitartrate, ℥vj; ginger, ℨii. Mix. Dose, 30 to 60 grains, in water, every 3 hours, as a hydragogue cathartic.
It is stated that the aqueous extract of jalap, the root having been previously exhausted of its resin by alcohol, will exert no cathartic influence, but will operate as a powerful diuretic, but I have not been able to procure this effect, though having made a trial in several cases (King). Three grains of jalap, taken an hour before each meal, act as a slight nauseant, destroying a desire for food among persons who are apt to eat too freely. If jalap is digested in ether, its nauseous taste and smell will be wholly removed without lessening its cathartic power. A biscuit is sometimes made for those to whom it is extremely nauseous and disagreeable; 5 drachms of jalap, 30 of sugar, and 4 ounces of flour, are made into 15 biscuits after the usual mode; 1 biscuit is a dose. The tendency of jalap to gripe and nauseate, may be obviated by adding to the dose 1 or 2 grains of camphor, or 3 grains of cloves. The dose of powdered jalap is from 10 to 30 grains (the aqueous extract ought not to be used, except as a diuretic); of the tincture, from 1 to 4 fluid drachms; the resin, or alcoholic extract, is given in from 2 to 8-grain doses, being usually rubbed up with sugar, or in emulsion, for the purpose of lessening its disposition to produce painful irritation of the intestinal mucous membrane. As a hydragogue, 2 drachms of the bitartrate of potassium are added to 10 or 30 grains of pulverized jalap. Convolvulin (rhodeoretin) purges violently in 3 or 4-grain doses, and appears to be the active principle of jalap. Specific jalap, 10 to 20 drops every 4 hours for its specific uses. Though not an anthelmintic, jalap is often given to hasten the expulsion of worm, after agents have been given for their stupefaction or destruction.
Specific Indications and Uses.—Constipation from deficient secretion of intestinal glands; pain and griping in lower bowel; colic, with stercoraceous vomiting; general gastro-intestinal torpor.
Related Species and Drugs.—Several related convolvulaceous tubers of Mexico and Brazil have been employed as purgatives. They are not, however, articles of general commerce.
TAMPICO JALAP.—This is the Mexican Purga de Sierra Gorda, and is derived from the Ipomoea simulans, Hanbury. It much resembles the jalap tuber in appearance, odor, and taste. While it is difficult to distinguish some of the tubers from those of true jalap, most of the Tampico tubers are smaller and more elongated, more corky and shrivelled, and show an absence of little scars crosswise the roots so noticeable in true jalap (Pharmacographia). It yields a resin (10 to 15 per cent). Flückiger obtained 10 per cent of it. It is completely soluble in ether. Spirgatis (1870) named the resin tampicin (C68H10O28). I is converted into tampicic acid (C68H120O34) by means of concentrated alkalies. Acids resolve it into sugar and tampicolic acid (C32H64O6), thus showing its glucosidal character, analogously to that of convolvulin. It has purgative properties.
Ipomoea turpethum, R. Brown; Turpeth root.—This is the Turbith végétal of the French Codex. It is not very similar in appearance to jalap. It contains a resin (4 per cent), of which turpethin, the ether-soluble portion, a glucosid, behaves like resin of jalap in relation to acids and alkalies. Bases convert it into turpethic acid, methyl-crotonic acid, traces of formic, and methyl-ethyl-acetic acids, etc. (see articles by N. Kromer, Oesterr. Zschr. f. Pharmacie, 1895, Nos. 18 to 24).
Ipomoea nil, Roth (Convolvulus nil, Linné; Pharbitis nil, Choisy).—Tropical regions and southern United States. Seeds called kaladana in India, and are slightly purgative. They are black, triangular, with a rounded back, and have a sweetish taste, followed by an acrid sensation. They yield pharbitisin (identical with convolvulin) and a volatile oil. The seeds are roasted and given in powder.
MECHOACAN.—This product, probably of a convolvulaceous plant, comes in gray or whitish circular sections or fragments, somewhat farinaceous, and destitute of the circles of resinous cells. It sometimes occurs as an adulterant of jalap, but its detection is not difficult. It is feebly cathartic.
Ɣ ORIZABA ROOT.—This is variously known as Woody, Light, or Fusiform jalap, Male jalap, Jalap tops or stalks, and is the Mexican Purgo macho. It is derived from the Ipomoea orizabensis, Ledanois. This root is fusiform, and sometimes occurs in commerce in transverse slices, but more frequently in rectangular blocks. Its longitudinal wrinkles are deeper than those of jalap. Its color is also lighter. From the latter it may be known by the radiations on transverse section, and by leaving, when fractured, projecting bundles of fibrous vessels. Chemically, it closely resembles jalap. Its chief constituent is jalapin (C34H56O16, or C68H112O32, Poleck), so named by Mayer (para-rhodeoretin of Kayser), and should not be confounded with the jalapin of Buchner and Herberger, which is convolvulin. Mayer's jalapin differs from convolvulin in that ether and acetone freely dissolve it. Poleck (1892) proposes for it the name orizabin, as Prof. Maisch has done in 1887. Alkalies change it into water-soluble jalapic acid (C68H118O35, or H2C17H28O9, Poleck). Diluted acids convert it into sugar and jalapinol (C32H62O7), insoluble in water; probably identical with jalapinolic acid (C32H60O6, or C16H30O3, Poleck, 1892), obtainable from scammony resin. Jalapin (orizabin) is oxidized by nitric acid to carbonic, isobutyric, and ipomic acid, the latter an isomer of sebacic acid (compare convolvulin). Jalapin (Mayer's) has been shown by Spirgatis to be identical with scammonin, both in chemical and purgative qualities, a fact more recently confirmed by Th. Poleck (see Jahresb. der Pharm., 1892, p. 80).
Ipomoea pandurata, Meyer (Convolvulus panduratus, Linné); Wild potato.—This plant, likewise known as Wild jalap, Man in the Ground, Mechameck, Man of the Earth, etc., has a perennial, very large, tapering root, with several stems from the same root, from 4 to 8 feet long, round, slender, purplish, smooth or nearly so, trailing or twining. Leaves 2 or 3 inches long, about the same width, broadly cordate at base, acuminate, entire, or wavy, alternate, sometimes panduriform, smooth, deep-green above, paler beneath, on long petioles. Flowers white, dull-purple toward the base, large, opening in the forenoon; peduncles axillary, longer than the petioles, cymose, branching at the top, several-flowered. Corolla large, campanulate, 2 or 3 inches long. Calyx smooth, 5-parted, naked; sepals ovate-oblong stamens white, the length of the tube; anthers oblong. Style white, thread-like; stigma capitate, bilobed. Capsule oblong, 2-celled, 4-seeded, without intermediate partitions (L.—W.—G.).
Wild potato is indigenous to the United States, growing in light and sandy soils, from Connecticut and west New York, southward and westward, and flowering from June to August; it rarely grows North, but is found in some parts of South America. The root is the medicinal part, it is very large, being from 2 to 8 feet in length, and from 2 to 4 or 5 inches in diameter, branched at the bottom, brownish-yellow externally, whitish and lactescent internally, furrowed lengthwise, and of a disagreeable odor and bitter, rather acrid taste; about 75 per cent in weight is lost in drying. It is generally met with in transverse, circular sections, which are somewhat tawny externally, whitish with diverging lines internally, and not readily powdered; the powder is somewhat grayish. Water or alcohol extracts its active properties, but diluted alcohol or spirits are its best solvents. It contains resin, bitter-extractive, sugar, starch, gum, a body resembling tannic acid, etc. The resin is purgative. It consists of an acid, and a nonacid portion. It is a glucosid, and exists to the extent of 1.5 per cent.
The active principles of this plant are unknown. It possesses mild cathartic properties, acting gently in doses of from 40 to 60 grains of the powdered root. The infusion taken in wineglassful doses every hour, has been effective in dropsy, strangury, and calculous affections. It seems also to exert an influence over the lungs, liver, and kidneys, without excessive diuresis or catharsis. The saturated tincture is more energetic than the powdered root, decoction, or extract. It is asserted that the Indians can handle rattlesnakes with impunity after wetting their hands with the milky juice of this root.
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.