Cambogia (U. S. P.)—Gamboge.
"A gum-resin obtained from Garcinia Hanburii, Hooker filius"—(U. S. P.). (Garcinia Morella, Desrousseaux, var. pedicellata, Hanbury).
COMMON NAMES: Gamboge, Camboge, Gutti, Gummi-resina gutti, Cambodia, Gutta gamba.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 33.
Botanical Source and History.—This plant differs from that of Garcinia Morella (G. pictoria), described below, in having pedicellate male flowers. It has glossy leaves resembling those of the laurel, and bears yellow flowers.
Gamboge was first brought to Europe by Admiral Van Neck, in 1603, who gave a specimen of it to Prof. Clusius, of Leyden (Amer. Jour. Pharm., 1837). In relation to the plant from which this gum-resin is derived, there was formerly much confusion. By some it was laid down as coming from Stalagmitis cambogioides, upon the authority of Murray, but Dr. Graham has satisfactorily determined that there is no such plant in existence. It was then supposed to be derived from trees of Ceylon, which produce gum-resins agreeing closely or entirely with the official gamboge (the Garcinia Cambogia and the Hebradendron cambogioides, which last was supposed to be the tree from which it was principally collected), though on merely presumptive evidence. The latter tree is not now recognized under the name Hebradendron, but is regarded by botanists as identical with Garcinia Morella of Desrousseaux. Hanbury also regards the G. elliptica, Wallich, as identical, the product of which is certainly identical with commercial gamboge. The matter was best presented by Mr. Hanbury, who investigated the subject, finding that the gum was the product of a variety of the above mentioned Garcinia Morella of Desrousseaux (Garcinia pictoria, Roxburgh; Hebradendron cambogioides, Graham), and to that variety he gave the name Garcinia Morella, var. pedicellata, on account of its pedicellate, male flowers. The younger Hooker, however, regarded it as sufficiently distinct from the Garcinia Morella to entitle it the rank of a species, and accordingly gave it the title, Garcinia Hanburii (see Hanbury, "On the species of Garcinia which affords Gamboge in Siam," Tr. Linn. Soc., Vol. 24, p. 487).
The Garcinia Morella, Desrousseaux, is a moderate-sized tree, with opposite petiolate, obovate-elliptical, coriaceous, smooth, entire, abruptly-acuminate, shining leaves, which are dark-green above and paler beneath. The flowers are unisexual, sessile, and axillary; the calyx membranous and persistent, consisting of 4 sepals; the corolla is 4-petaled, while the fruit is a pleasant, saccharine, quadrilocular berry, about the size of a cherry, crowned with a sessile stigma, containing 1 seed in each division (L). In order to obtain the gum-resin incisions are made into the tree, or a large slice is pared from the bark, from which the juice flows thick, viscid, and bright-yellow, which is scraped off and dried in the sun. If left on the tree, it speedily concretes into dry tears or irregular masses. It is more generally collected, however, by making incisions into the bark, into which bamboo joints are inserted to catch the oozing fluid, which subsequently solidifies. It is removed from the bamboo by slowly rotating them over a fire until the water has dried out sufficiently to allow the receptacle to be detached from the hardened gamboge. The first process described is that by which the Ceylon gamboge is collected. The best kinds are the pipe gamboge and Ceylon gamboge, which last is seldom found in our country. The pipe gamboge consists of cylindrical pieces, often cohering together, forming irregular masses weighing several pounds. Lump or cake gamboge occurs in masses of several pounds weight; it differs from the best pipe gamboge in containing between 5 and 10 per cent of starch, and fragments of wood, twigs, and air cells. Gamboge is used in painting as a yellow pigment, known in Europe as gummigutt. It is collected in Siam and Cochin-China, and principally in Cambodia, and sent to Singapore, Saigon, and Bangkok, from which places it is imported into this country.
Description.—Gamboge, to meet the official demands, should conform to the following description and tests: "In cylindrical pieces, sometimes hollow in the center, 2 to 5 Cm. (3/4 to 2 inches), in diameter, longitudinally striate on the surface; fracture flattish-conchoidal, of a waxy luster, orange-red; in powder bright yellow; inodorous; taste very acrid; the powder sternutatory. Gamboge is partly soluble in alcohol and in ether. When triturated with water it yields a yellow emulsion, and forms, with solution of potassium or sodium hydrate, an orange-red solution, from which, on addition of hydrochloric acid, a yellow resin is precipitated. Boiled with water, gamboge yields a liquid which, after cooling, does not become green with iodine T.S. (absence of starch)"—(U. S. P.). Ether and water when used alternately, dissolve the whole of pure gamboge. Alcohol dissolves all the resin, leaving the gummy matter, and ammoniated alcohol forms a solution with it which is not changed by water.
Chemical Composition.—Gamboge consists mainly of resin (71.6 to 74.2 per cent), gum (21.8 to 24 per cent) moisture (4.8 per cent), traces of starch and woody fiber (Christison). The resin has the nature of an acid (gambogic acid), and is the active principle of the gum. Its specific gravity is 1.221. It forms soluble salts with alkalies, and insoluble precipitates with salts of heavy metals; this class of compounds has been called gambogiates. The resin is obtained by extracting gamboge with ether (whereby the gum is left behind), and evaporating the solution to dryness. It occurs in brittle masses of a deep orange color, insoluble in water, but soluble in alcohol, ether, chloroform, carbon disulphide, and caustic alkali, with which it forms an orange-red solution, from which acid again precipitates the yellow resin. Gambogic acid imparts a perceptible yellow hue to 10,000 times its weight of spirit or water (C.).
Pereira gives the following as the tests for distinguishing gamboge: "Gamboge emulsion becomes transparent and deep-red on the addition of potassa, forming gambogiate of potassium. Digested in alcohol or ether, gamboge yields orange-red tinctures (solutions of gambogic acid). The ethereal tincture dropped on water yields, on the evaporation of the ether, a thin, bright-yellow, opaque, film or scum (gambogic acid), soluble in caustic potash. The alcoholic tincture dropped into water, yields a bright, opaque, yellow emulsion, which becomes clear, deep red, and transparent, on the addition of caustic potash. The gambogiate of potassium (obtained by any of the above processes), gives, if the alkali be not in excess, with acids, a yellow precipitate (gambogic acid); with acetate of lead, a yellow precipitate (gambogiate of lead); with sulphate of copper, brown (gambogiate of copper); and with the salts of iron, dark brown (gambogiate of iron)."
Hlasiwetz and Barth (1866), in fusing the purified resin of gamboge with potassium hydroxide, obtained several acids, among them acetic, pyro-tartaric (C5H8O4), and isuvitinic (C6H4CH2[COOH]2) acids; also phloroglucin (C6H3[OH]3). The vapor given off during fusion had the odor of balm and lemons. The presence of wax has also been indicated by Hurst, in 1889 (Flückiger).
Action, Medical Uses, and Dosage.—In large doses gamboge is a powerful irritant, causing gastro-enteritis and death; it is said to produce diffuse inflammation of the cellular tissue, when applied beneath the skin. On account of its severity of action, and its liability to cause serious symptoms, it is seldom employed sing as a purgative; yet when combined with other cathartics it forms a safe and excellent physic. It may, however, be safely administered alone in moderate doses, by reducing it to a state of fine division with other comparatively inert powders, as sulphate or bitartrate of potassium. It thus operates effectually as a hydragogue, without occasioning much tormina or constitutional exhaustion. In medicinal doses, it is a drastic, hydragogue cathartic, causing nausea, griping, and copious watery stools, on which account it is often used in dropsy, in combination with squills, cream of tartar, etc. It has also been used for the expulsion of tapeworm, in torpor of the bowels, dysmenorrhoea, etc. Two grains of sulphate of quinine combined with 1 1/4 grains of gamboge, and administered 3 times a day, have been highly recommended in cases of long-continued constitutional debility, with constipation. United with an alkali, it proves diuretic.
Its use is contraindicated in gastritis, enteritis, during pregnancy, menorrhagia, hemorrhoids, in excited, irritable, or diseased uterus, and where there is irritation or disease of the urinary organs. When taken in large doses, or when it acts with severity, the best remedy to counteract its dangerous effects is a solution of some alkaline substance, as sodium bicarbonate, to be followed by general treatment if inflammatory symptoms be present. Dose, in pill, powder, or alkaline solution, from 1 to 15 grains; the larger doses given in small quantities, and repeated at short intervals until it operates.