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CINCHONA

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Originally appearing in Volume V06, Page 370 of the 1911 Encyclopedia Britannica.
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CINCHONA , the generic name of a number of trees which belong to the natural See also:

order See also:Rubiaceae. Botanically the genus includes trees of varying See also:size, some reaching an See also:altitude of 8o ft. and upwards, with See also:evergreen leaves and See also:deciduous stipules. The See also:flowers are arranged in panicles, See also:white or pinkish in See also:colour, with a pleasant odour, the calyx being 5-toothed See also:superior, and the corolla tubular, 5-lobed and fringed at the margin. The stamens- are 5, almost concealed by the tubular corolla, and the ovary terminates in a fleshy disk. The See also:fruit is an ovoid or sub-cylindrical See also:capsule, splitting from the See also:base, and held together at the See also:apex. The numerous seeds are See also:flat and winged all See also:round. About 40 See also:species have been distinguished, but of these not more than about a dozen have been economically utilized. The See also:plants are natives of the western mountainous regions of See also:South See also:America, their See also:geographical range extending from o° N. to 22° S. See also:lat.; and they flourish generally at an See also:elevation of from 500o to 8000 ft. above See also:sea-level, although some have been noted growing as high up as I I,000 ft., and others have been found down to 2600 ft. The trees are valued solely on See also:account of their bark, which See also:long has been the source of the most valuable febrifuge or antipyretic See also:medicine, See also:quinine (q.v.), that has ever been discovered. The earliest well-authenticated instance of the medicinal use of cinchona bark is found in the See also:year 1638, when the countess of Chinchon (hence the name), the wife of the See also:governor of See also:Peru, was cured of an attack of See also:fever by its See also:administration. The medicine was recommended in her See also:case by the corregidor of Loxa, who was said himself to have practically experienced its supreme virtues eight years earlier. A knowledge of the bark was disseminated throughout See also:Europe by members of the Jesuit brotherhood, whence it also became generally known as See also:Jesuits' bark.

According to another account, this name arose from its value having been first discovered to a Jesuit missionary who, when prostrate with fever, was cured by the administration of the bark by a South See also:

American See also:Indian. In each of the above instances the fever was no doubt See also:malaria. The procuring of the bark in the dense forests of New See also:Granada, See also:Ecuador, Peru and See also:Bolivia is a See also:work of See also:great toil and hardship to the Indian cascarilleros or cascadores engaged in the pursuit. The trees grow isolated or in small clumps, which have to be searched out by the experienced cascarillero, who laboriously cuts his way through the dense See also:forest to the spot where he discovers a See also:tree. Having freed the See also:stem from adhering parasites and See also:twining plants, he proceeds, by beating and cutting oblong pieces, to detach the stem bark as far as is within his reach. The tree is then felled, and the entire bark of stem and branches secured. The bark of the smaller branches, as it dries, curls up, forming " quills," the thicker masses from the stems constituting the " flat " bark of See also:commerce. The drying, packing and transport of the bark are all operations of a laborious description conducted under most disadvantageous conditions. The enormous medicinal See also:consumption of these barks, and the wasteful and reckless manner of procuring them in America long ago, caused serious and well-grounded See also:apprehension that the native forests would quickly become exhausted. The See also:attention of See also:European communities was See also:early directed to the See also:necessity of securing steady and permanent supplies by introducing the more valuable species into localities likely to be favourable to their cultivation. The first actual See also:attempt to See also:rear plants was made in See also:Algeria in 1849; but the effort was not successful. In 1854 the Dutch See also:government seriously undertook the task of introducing the trees into the See also:island of See also:Java, and an expedition for that purpose was fitted out on an adequate See also:scale.

Several hundreds of See also:

young trees were obtained, of which a small See also:pro-portion was successfully landed and planted in Java; and as the result of great attention the cultivation of cinchona plantations in that island became highly prosperous and promising. The desirability of introducing cinchonas into the See also:East Indies was urged in a memorial addressed to the East See also:India See also:Company between 1838 and 1842 by See also:Sir See also:Robert See also:Christison and backed by Dr See also:Forbes See also:Royle; but no active step was taken till 1852, when, again on the See also:motion of Dr Royle, some efforts to obtain plants were made through consular agents. In the end the question was seriously taken up, and Sir Clements R. See also:Markham was appointed to See also:head an expedition to obtain young trees from South America and convey them to India. The transference of the plants was attended with considerable difficulty, but in 1861 under his superintendence a See also:consignment of plants was planted in a favourable situation in the Nilgiri Hills. For several years subsequently additional supplies of plants of various species were obtained from different regions of South America, and some were also procured from the Dutch plantations in Java. Now the culture has spread over a wide See also:area in See also:southern India, in See also:Ceylon, on the slopes of the Himalayas, and in See also:British See also:Burma, and has become widely spread through the tropics generally. The species grown are principally Cinchona officinalis, C. Calisaya, C. succirubra, C. pitayensis, and C. Pahudiana, some agreeing with certain soils and climates better than others, while the yield of alkaloids and the relative pro-portions of the different alkaloids differ in each species. The See also:official " bark " of the British See also:Pharmacopoeia is that of Cinchona succirubra or red bark. It is imported in the See also:form of quills or recurved pieces, with a rough See also:brown See also:outer See also:surface and a deep red inner surface, forming a reddish brown odourless See also:powder, which has a See also:bitter, astringent See also:taste.

The British Pharmacopoeia directs that the bark, when used to make the various medicinal preparations, shall contain not less than 5 nor more than 6% of See also:

total alkaloids, of which at least one-See also:half is to be constituted by quinine and cinchonidine. The preparations of this bark are four: a liquid See also:extract, standardized to contain 5% of total alkaloids; an See also:acid infusion; a See also:tincture standardized to contain 1% of total alkaloids; and a See also:compound tincture which must possess one-half the alkaloidal strength of the last. The only purpose for which these preparations of cinchona bark should be used is as tonics; and even when this is the desired See also:action there are many reasons why the See also:alkaloid should be preferred, even though the See also:recent introduction of standardization removes one of the See also:chief objections to their use. The See also:pharmacology of red bark, dependent-as it is almost entirely upon the contained quinine, will not here be discussed (see QUININE). But the See also:composition of cinchona bark is a See also:matter of importance and See also:interest. The bark contains, in the first See also:place, five alkaloids, of which all but quinine may here be dealt with. Quinidine, C2aH24N202, is isomeric with quinine, from which it differs in crystallizing in prisms instead of needles, in being dextro- and not laevo-rotatory, and in being insoluble in See also:ammonia except in much excess. Cinchonine has the See also:formula C19H22N20, quinine being methoxy cinchonine, i.e. C,9H21(OCH,)N20. It occurs in inodorous, bitter, colourless prisms; unlike the two alkaloids already named, does not yield a See also:green colour with See also:chlorine See also:water and ammonia; is dextro-rotatory; not fluorescent, and practically insoluble in ammonia and in See also:ether. A See also:fourth alkaloid, cinchonidine, is isomeric with cinchonine, which yields it when boiled with amyl alcoholic potash, but is laevo-rotatory, slightly soluble in ether, and faintly fluorescent. When red bark is extracted with dilute hydrochloric acid, the product filtered, and excess of See also:sodium See also:hydrate added thereto, quinine and ,quinidine are precipitated: on concentrating the See also:mother liquor, cinchonine falls down, and on further concentration with addition of still more See also:alkali, cinchonidine is thrown out.

Yellow bark, which is not official, yields 3 % of quinine, and See also:

pale bark about to % of total alkaloids, of which hardly any is quinine, cinchonine and quinidine being its chief constituents. The various forms of bark also yield a very small quantity of an unimportant alkaloid, conquinannine. In addition to the above, red bark contains quinic acid, C7H1206, which is closely allied to benzoic acid and is excreted in the urine as hippuric acid. There also occurs chinovic acid, derived from a See also:glucoside chinovin, which occurs as such in the bark. Besides a trace of volatile oil which gives the bark its characteristic odour, and cinchona red (the bark pigment). there occurs about 2% of eincho-tannic acid, closely allied to tannic acid and giving the bark its astringent See also:property. Cinchona is never used, however, in order to obtain an astringent action. The importance of recognizing the complex and inconstant composition of cinchona bark lies, as in so many other instances, in this—that the physician who employs it can have only a very imperfect knowledge of the See also:drug he is using. The latest work on the action of these alkaloids has shown that cinchonine has a tendency to produce-See also:convulsions in certain patients, and that this action is a still more marked feature of cinchonidine and cinchonamine. Even small doses administered to epileptics increase the number of their attacks. They will probably be classified later among the convulsive poisons. The use of cinchona bark and its preparations, now that definite active principles can be readily obtained and precisely studied, is almost entirely to be deprecated. Quinidine is almost as powerful an antidote to malaria as quinine; cinchonidine has about two-thirds the See also:power of quinine, and cinchonine less than one-half.

End of Article: CINCHONA

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