Jalap consists of the dried tubercules of Ipomoea Purga, Hayne (N.O. Convolvulaceae), a climbing plant indigenous to the eastern slopes of the Mexican Andes. It is also official in the U.S.P. The tubercules are collected and then dried in nets over the fire, the larger ones being sliced to facilitate drying. The drug occurs in irregularly, oblong-ovoid, napiform or fusiform roots, from 2.5 to 7.5 centimetres or more in length, the larger roots being cut. Externally they are dark brown, furrowed, and wrinkled, and marked with smaller transverse scars. They are hard and heavy, and break with difficulty, the internal surface being yellowish-grey or dull brown in colour. A transverse section exhibits irregular dark lines, often concentrically arranged, due to the formation of secondary cambium tissue. The taste of the drug is at first sweet, but afterwards acrid and disagreeable. Powdered jalap is characterised by the abundant starch, much of which may be found uninjured by heat; the grains are simple or compound (2 to 4); the former are rounded or ovoid, and measure commonly 8μ to 50μ in length; droplets of gum-resin are also abundant. Calcium oxalate occurs in rosette crystals; sclerenchymatous cells and portions of pitted vessels may also be found, but sclerenchymatous fibres should not be present. The drug yields about 6 per cent. of ash. The following substitutes for true jalap appear in commerce:—Tampico jalap, the root of I. simulans, Hanbury. It may be distinguished by its irregular shape, convoluted surface, and absence of lenticels. It yields about 10 per cent. of resin (tampicin), which is entirely soluble in ether, and is identical with the ether-soluble resin of true jalap (scammonin). Orizaba jalap, also known as male or woody jalap, is the root of I. orizabensis, Ledenois. It occurs mostly as transverse slices, 5 to 10 centimetres long, and 1.5 to 2.0 centimetres thick, or portions of slices of large roots, and shows concentric rings from which coarse fibres protrude; smaller roots may be 2.5 centimetres in diameter and 8 to 10 centimetres long. The drug contains about 17 or 18 per cent. of resin (scammonin or orizabin), which is soluble in ether and identical with the ether-soluble resin of jalap. Large quantities of this root are used for the production of the resin (scammony resin), and it should be observed that the term jalapin is frequently applied in Germany to the ether-soluble resin obtained from scammony and jalap, whereas in England it is applied to the ether-insoluble resin of true jalap.
Constituents.—The tubercules contain resin, sugar, and starch, together with protein, calcium oxalate, etc. The resin, which is the most important of these, varies from 5 to 18 per cent., 8 to 12 per cent. being frequently found. When treated with ether a portion only (5 to 20 per cent.) is dissolved; this appears to be identical with the resin obtained from scammony root and from the root of I. orizabensis, and has been designated scammonin (orizabin). Jalapa, U.S.P., should contain not less than 7 per cent. of total resin, of which not more than 15 per cent. should be soluble in ether. The portion (about 90 per cent.) insoluble in ether is properly named jalapin, but has also been termed convolvulin and jalapurgin. Both resins are glucosidal, and can be hydrolysed by boiling with dilute mineral acid, scammonin yielding scammonolic acid and glucose, and jalapin yielding jalapinol (convolvulinolic acid) and glucose. Part of the starch present has been gelatinised by the heat employed in drying the root.
Action and Uses.—Jalap is a powerful purgative, producing copious watery evacuations. In large doses it causes considerable pain, and its preparations should not be used by those suffering from gastric or intestinal inflammation. Its action is due to the alcohol-soluble resins (see Jalapae Resina). Powdered jalap is too bulky for use in pills, and resin of jalap or extract of jalap is more suitable for this purpose. The latter contains both the gum and resin of the crude drug. Jalap appears to act only in the presence of bile, and the addition of soap increases its purgative power. A tincture and a compound tincture are prepared, the latter especially for use in India and the Colonies.
Dose.—3 to 12 decigrams (5 to 20 grains).
- Extractum Jalapae, B.P.—EXTRACT OF JALAP.
- Jalap, in coarse powder, 100; alcohol, 500; distilled water, 1000. Macerate the drug in the alcohol for seven days, press, filter, and recover the alcohol by distillation, leaving a soft extract, then macerate the marc with the water for four hours, strain through flannel, evaporate the product to a soft extract, mix this with the alcoholic extract, and evaporate the mixture to a firm extract at a temperature not exceeding 60°. Extract of jalap is prescribed in pill form for its hydragogue cathartic action. The spirit-soluble portion of the extract contains the active glucosidal resins. The gummy and sugary matters of the watery extract subdivide the resin and make it more soluble. A little soap may be added to assist the action of the extract. Dose.—1 to 5 decigrams (2 to 8 grains).
- Pilulae Jalapae Compositae, B.P.C.—COMPOUND JALAP PILLS.
- Each pill contains 1 grain of jalap, 2 grains of Barbados aloes, 1/2 grain of colocynth, 1/2 grain of soft soap, and 1/6 grain of oleoresin of ginger. Dose.—1 or 2 pills.
- Pilulae Jalapae et Hydrargyri Subchloridi Compositae, B.P.C.—COMPOUND JALAP AND MERCUROUS CHLORIDE PILLS. Syn.—Compound jalap and Calomel Pills.
- Each pill contains 1 grain of jalap, 1 1/2 grains of Barbados aloes, grain of colocynth, 1/2 grain of soft soap, 1/3 grain of mercurous chloride, and 1/6 grain of oleoresin of ginger. Dose.—1 or 2 pills.
- Pulvis Jalapae, Compositus, B.P.—COMPOUND POWDER OF JALAP. Syn.—Compound jalap Powder.
- Jalap, in powder, 5; acid potassium tartrate, in powder, 9; ginger, in powder, 1. Mix the powders intimately. This preparation is a hydragogue cathartic, employed in dropsy and chronic Bright's disease. Dose.—1 to 4 grammes (20 to 60 grains).
- Pulvis Jalapae Compositus, U.S.P.—COMPOUND POWDER OF JALAP, U.S.P.
- Jalap, in powder, 35; acid potassium tartrate, in powder, 65.
- Tinctura Jalapae, B.P.—TINCTURE OF JALAP.
- Jalap, in No. 40 powder, 20; alcohol (70 per cent.), a sufficient quantity. Add 10 of alcohol to the drug, pack in a percolator, and percolate with more alcohol until the product measures 60; then press the marc, mix the expressed liquid with the percolate, filter after standing for twenty-four hours, and adjust the strength of the tincture, so that the finished product shall contain 1.5 per cent. w/v of jalap resin. Tincture of jalap is used as a hydragogue cathartic to remove fluid from the body, relieve congestion, and lower blood pressure. Mixtures containing this tincture require the addition of one-eighth of their volume of mucilage of tragacanth to suspend the resin. Dose.—2 to 4 mils (1/2 to 1 fluid drachm).
- Tinctura Jalapae, Composita, I.C.A.—COMPOUND TINCTURE OF JALAP.
- Jalap, in No. 40 powder, 8; scammony, in No. 40 powder, 2; turpeth, in No. 40 powder, 1; alcohol (60 per cent.), sufficient to produce 100. Add 10 of the alcohol to the mixed powders to moisten the mixture and complete the percolation process. Compound tincture of jalap is official for use in India, the Eastern Colonies, and the North American Colonies. Mixtures containing this tincture require the addition of one-eighth of their volume of mucilage of tragacanth to suspend the resin. Dose.—2 to 4 mils (1/2 to 1 fluid drachm).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.