Habitat. E. Mexico, in damp, rich, shady woods; cultivated in India. Syn. True Jalap, Vera Cruz Jalap, Radix Jalapae; Fr. Jalap - tubereux - officinal; Ger. Tubera Jalapae, Jalaoenwurzel. Jalaoenknollen. Jalape. Ex-o-go'ni-um. L. fr. Gr.
offspring - i. e., parts of generation (stamens, pistil) exserted - extended above corolla.
Pur'ga. L. fr. purgo, purgare, to purge, cleans, purify - i. e., its cathartic action on the system.
Jal'a-pa. L. named after Jalapa or Xalapa, a city in Mexico, whence imported.
Jal'ap. Formerly jal'op, English abbreviation from Jalapa.
Plant. - Perennial twining herb; stems numerous, slender, twisted, furrowed, smooth, purplish, 3.6-6 M. (12-20°) long, twining around neighboring objects; leaves exstipulate, 10-12.5 Cm. (4-5') long, cordate, entire, smooth, pointed, under side paler, prominently veined, on long petioles; flowers Sept.-Nov., purple, salver-shaped, tube 5 Cm. (2') long, limb 5-7.5 Cm. (2-30 wide, in 3-flowered cymes, stamens exserted (exogonium). Root, fusiform, irregularly ovoid, pyriform, upper end more or less rounded, lower slightly tapering, 4-15 Cm. (1 3/5 - 6') long, 12-60 Mm. (½-2 2/3') thick; large roots often incised, cut into pieces; dark brown, longitudinally wrinkled or furrowed, numerous lenticels; hard, compact, non-fibrous; internally dark brown, mealy or waxy; bark 1-2 Mm. (1/25 - 1/12') thick, outer bundles separated from outer cortical layer by distinct, brown cambium zone; odor slight, distinctive, smoky; taste somewhat sweet, acrid. Powder, light brown; microscopically - numerous starch grains, .003-.035 Mm. (1/8325 - 1/725') broad, calcium oxalate rosette aggregates, tracheae, laticiferous vessels with brownish resinous masses. Solvents: diluted alcohol extracts virtues completely; water or alcohol alone only partially, each taking out a portion of purgative property, the alcoholic solution being more griping than the aqueous. Dose, gr. 5-20 (.3-1.3 Gm.).
Adulterations. - False Jalap roots (Ipomoea simulans, I. oriza-bensis), and roots of allied species; immature jalap roots, collected at improper times and containing very little resin; jalap roots deprived of resin by soaking in alcohol, becoming sticky to the touch, darker internally and thereby easily recognized; roots of other species of
Exogonium and Ipomoea genera; mealy jalap, resembling the true root, but with mealy fracture and very few resin cells.
Commercial. - Plant resembles our Morning-glory, demands rich forest-loam and a climate suitable to Cinchona; grows on the eastern slope of the Mexican Andes, 1,500-2,400 M. (5,000-8,000°) elevation, flourishes well in the Neilgherry, India, and is cultivated in Jamaica. It is trained upon trellises and various supports, and not disturbed
Fig. 322. - Exogonium purga.
until 3 years old and only thereafter every third year. Roots are dug in all seasons (hence varying appearance and strength), but chiefly in the spring, when young shoots appear, and in the autumn (best), after aerial stems have decayed, then washed, placed into nets and dried by holding over fire (there being no sunshine during the rainy season), which imparts a slight smoky odor and hydrates much of the starch; prior to desiccation the very large pieces are divided into halves, quarters, or transversely that tends to make it less desirable; after drying it is put into bags (100-200 pounds; 45-90 Kg.) and shipped from Vera Cruz.
.. Constituents. - Resin 7-15-22 p. c., starch, gum 15 p. c, sugar 2 p. c., bassorin, coloring matter, ash 5-G.5 p. c.
Fig. 323. - Jalap tubers, small sized: 1, fusiform; 2, pear-shaped; 3, date-shaped;
Resin. - Consists of: 1. Jalapin (probably identical with scammo-nin), 4-10 p. c, soft, waxy, soluble in ether, alkalies, reprecipitated by acids, and medicinally inert. 2. Jalapurgin, rhodeoretin, convolvulin, C62H100O32, 90-96 p. c, a white, odorless glucoside, hard, insoluble in ether, soluble in alkalies, more of an irritant than jalapin, and the chief active constituent; converted by alkalies into jalapurgic (convolvul(in)ic acid, which is soluble in water), C28H52O14, by warming with diluted acids or emulsion into glucose, volatile methyl-ethyl-acetic acid, C5H10O2, and convolvulic acid, and this latter by continued action into glucose and crystalline convolvulinolic acid, C16H30O3; the name jalapin has unfortunately been assigned to both resins.
Preparations. - 1. Pulvis Jalapoe Compos-itus. Compound Powder of Jalap. (Syn., Pulv. Jalap. Co., Pulvis Purgans - Cathar-ticus or Jalapae tartaratus; Fr. Poudre de Jalap composee; Ger. Jala-penpulver mit Weinstein.)
Manufacture: 35 p. c. Triturate together jalap 35 Gm., potassium bitartrate 65 Gm.; mix thoroughly, pass through No. 60 sieve. It is light brown; microscopically - numerous angular, rectangular fragments slowly soluble in water or hydrated chloral T. S., strongly polarizing light with display of colors (potassium bitartrate), numerous
Fig. 324. - Jalap tuber: transverse section.
starch grains, .003-035 Mm. (1/8325-1/725') broad, few fragments of jalap with laticiferous vessels and parenchyma having tracheae and rosette aggregates of calcium oxalate. Dose, gr. 15-60 (1-4 Gm.).
2. Resina Jalapoe. Resin of Jalap. (Syn., Res. Jalap.; Br. Jalapae Resina; Fr. Resine de Jalap; Ger. Jalapenharz.)
Manufacture: Macerate, percolate 100 Gm. with alcohol until the percolate when dropped into water only produces slight turbidity (250 Ml. (Cc.)), reclaim alcohol until percolate reduced to 25 Gm., and add this, constantly stirring, to water 300 Ml. (Cc.), let precipitate subside, decant supernatant liquid, wash precipitate twice by decantation, each time with water 100 Ml. (Cc), drain, dry on water-bath. It is in yellowish-brown masses, fragments, breaking with resinous, glossy fracture, translucent at edges, or yellowish-brown powder, slight, peculiar odor, somewhat acrid taste, permanent, soluble in alcohol, insoluble in carbon disulphide, benzene, fixed or volatile oils; alcoholic solution faintly acid. Tests: 1. Shake occasionally for an hour in a stoppered flask 1 Gm. with 10 Ml. (Cc.) of chloroform, evaporate filtrate, dry residue - should weigh .3 Gm. 2. Dissolve in ammonia water (5) - solution not gelatinous on standing; acidify with hydrochloric acid - only slight turbidity (abs. of rosin, guaiac, resins). Impurities: Rosin, guaiac, aloin, acid resins, orizaba, other resins, water, soluble substances. Dose. gr. 1-5 (.06-.3 Gm.).
Prep.: 1. Piluloe Catharticoe Compositoe, resin of jalap 1/3 gr. (.02 Gm.).
Unoff. Preps.: Abstract (alcohol), dose, gr. 2-5 (.13-3 Gm.). Extract (alcohol), dose, gr. 2-10 (.13 - .6 Gm.). Fluidextract (alcohol), dose, eij-10 (.13 - .6 Ml. (Cc.))- Tinctura Jalapoe 20 p. c. (67 p. c. alcohol), dose, 3ss-l (2-4 Ml. (Cc.)). Tinctura Jalapoe Composita, 12.5 p. c, + resin of scammony 3 p. c, 67 p. c. alcohol q. s., dose, 3ss-l (2-4 Ml. (Cc.)).
Properties. - Hydragogue cathartic, diuretic. Has no effect until the duodenum is reached, where with the bile it forms a purgative compound that stimulates vascularity, peristalsis, and profuse secretion from intestinal glands, with no action on biliary flow; usually acts in 4 hours. It is less irritating than gamboge, podophyllum, or scammony, but occasionally gripes, nauseates, and vomits. Often given to children for worms, as it has little taste and a safe action. Excessive doses produce dangerous hypercatharsis. Jalapurgin (convolvulin) in large doses is likewise an active irritant or poison.
Uses. - Dropsy, constipation, in febrile and inflammatory affections, head troubles; was introduced into Europe early in the 17th century, and is even now quite popular, being combined usually with calomel, cream of tartar, etc.