resin drug plant mexico
JALAP, a cathartic drug consisting of the tuberous toots of Exogonlum Purga, Benth., a convolvulaceous plant growing on the eastern declivities of the Mexican Andes at au elevation of 5000 to 8000 feet above the level of the sea, more especially about the neighbourhood of Chiconquiaco, and near San Salvador on the eastern slope of the Cofre de Perote. In these localities, where the temperature varies during the day from 60° to 75° Fahr. (15° to 24° C.), and rain falls almost every day, it flourishes in the deep rich soil of shady woods. Jalap has been known in Europe since the beginning of the 17th century, and derives its name from the city of Jalapa in Mexico, near which it grows, but its botanical source was not accurately determined until the year 1829, when Dr Coxe of Philadelphia published a description and coloured figure taken from living plants sent him two years previously from Mexico. The Jalap plant has slender herbaceous twining stems, with alternately-placed cordate acuminate leaves sharply pointed at the basal angles, and salver-shaped deep purplish-pink flowers. The underground stems are slender and creeping ; their vertical roots enlarge and form turnip-shaped tubers, which, as they do not bear leaf organs on their surface, are sometimes called tubercules. The roots are dug up in Mexico throughout the year, and are suspended to dry in a net over the hearth of the Indians' huts, and hence acquire a smoky odour. The large tubers arc often gashed to cause them to dry more quickly. In appearance they vary from spindle-shaped to ovoid or globular, and in size from a pigeon's egg to a man's fist. Externally they are brown, and marked with small transverse paler scars, and internally they present a dirty white resinous or starchy fracture. The ordinary drug is distinguished in commerce as Vera Cruz jalap, from the name of the port whence it is shipped. The average annual imports into Great Britain have been estimated at 180,000 lb.
Jalap has been cultivated for ten years past in India, at Ootacamund, and grows there as easily as a yarn, often producing clusters of tubers weighing over 9 lb ; but these, as they differ in appearance from the commercial article, have not as yet obtained a place in the English market. They are found, however, to be rich in resin, containing 18 per cent. In Jamaica also the plant has been grown, at first amongst the cinchona trees but more recently in new ground, as it was found to exhaust the soil. The 1880 crop of jalap in Jamaica amounted to 14,294 lb, and sold in the fresh state for £62, 3s. 8d. Some of it was exported to the London market.
Jalap owes it properties to jalapin, a resin which is present in it to the extent of 12 to 18 per cent. According to Mayer'. its composition is C„H„010. Jalapin is soluble in alcohol, but insoluble in ether and bisulphide of carbon. Jalap also contains in small quantity convolvulin, a resin soluble in ether, homologous with jalapin, and of the composition C34H550„. It yields also about 19 per cent. of sugar according to Guibourt, and starch, gum, uncrystallizable sugar, and colouring matter.
Besides Mexican or Vera Cruz jalap, a drug called Tampico jalap has been imported during the last few years in considerable quantity. It has a much more shrivelled appearance and paler colour than ordinary jalap, and lacks the small transverse scars present in the true drug. It differs also in containing in the place of jalapin a resin identical with the convolvulin above mentioned, and with the para-rhodeoretin of Kayser, which exists in it to the extent of 11 per cent. This kind of jalap, the Purga de Sierra Gorda of the Mexicans, was traced by Hanbury to Iponxxa simulans, Hanbury. It grows in Mexico along the mountain range of the Sierra Gorda in the neighbourhood of San Luis de la Paz, from which district it is carried down to Tampico, whence it is exported. A third variety of jalap known as woody jalap, male jalap, or Orizaba. root, or by the Mexicans as Purgo macho, is derived from Ipomma orizabensis, Ledanois, a plant of Orizaba. The root occurs in fibrous pieces, which are usually rectangular blocks of irregular shape, 2 inches or more in diameter, and are evidently portions of a large root. It is only occasionally met with in commerce. The resin contained in it is identical with that found in Tampico jalap.
According to Dr W. Rutherford, jalap acts as a powerful hepatic and intestinal stimulant. It is used as a hydragogue cathartic in combination with cream of tartar in dropsy, and in all cases where it is desirable to cause copious watery evacuation, also as a vermifuge. Buchheim asserts that jalap is only purgative when combined with bile, in which the resin is soluble.