Cinchona Bark

Cinchona Bark (or Peruvian bark), Cortex Chinae, more correctly Cortex Cinchonae (Pharmacopoeia of the USSR), is obtained mainly from cultivated cinchona trees and only in insignificant quantities from wild-growing cinchonas: Cinchona ledgeriana Moens, Cinchona succirubra Pavon, Cinchona officinalis Hooker fil., and some others; all belong to the family Rubiaceae. Cinchona calisaya, which provides bark with an insignificant quinine content, belongs to the same family. The 7th Pharmacopoeia of the USSR requires Cinchona bark from cultivated Cinchona succirubra Pavon, in which, after drying at 100°, there must be no less than 6.5% alkaloids. Cinchona bark has the appearance of channelled pieces 20–60 cm, rarely up to 1 m long and 2–4 mm thick, gray on the outside, often silvery-white; in places where the periderm has been stripped, it is light brown; it is wrinkled, with lenticels and longitudinal and transverse cracks. The inner surface of the bark is smooth, longitudinally fibrous, and reddish-brown; in young bark, it has a distinctly yellowish tint. The taste of the bark is bitter. Upon sublimation of Cinchona bark powder in a dry test tube, a tar-like mass in the form of tiny carmine-red droplets collects on the cold walls of the test tube (Grahe's test). The alkaloid quinine in Cinchona bark is located in the parenchyma tissue. If the cambial layer of the cinchona tree bark develops particularly abundantly, then in such cases the Cinchona bark is rich in quinine. In practice, this is achieved by partial removal of Cinchona bark from the trunks of cinchonas while preserving the cambium and the phloem closest to it, from which new bark arises.

The homeland of cinchona trees is considered to be South America, where cinchonas grow in the wild in forests on the slopes of the Cordillera mountains between 10° north and 19–22° south latitude, at an altitude of 800–3,000 m. Some tribes of the native population had long known the antipyretic properties of Cinchona bark; they became known to Europeans in 1638, when the wife of the Viceroy of Peru, the Countess del Cinchon, recovered from a fever after taking Cinchona bark. From 1640, Cinchona bark was brought to Europe and quickly gained recognition as the best remedy at that time against marsh fever and spread under the name Pulvis Comitissae (Countess's powder), as well as under the name Pulvis patrium (powder of the holy fathers), and others. In 1820, Pelletier and Caventou isolated an alkaloid from Cinchona bark. In 1865, the English merchant Charles Ledger managed, with the help of a cascarilliero (a collector of Cinchona bark), to obtain seeds of a cinchona that produced excellent bark. Ledger sold the cinchona seeds to Holland, which already possessed 20,000 young cinchonas on its plantations two years later. After that, cinchonas began to be cultivated in Java, Ceylon, India, South America, Mexico, and Jamaica. In the USSR, the cultivation of the cinchona tree is carried out in the Batumi Botanical Garden. In the Sukhumi nursery of the All-Union Institute of Applied Botany and New Cultures (VIR), work has been carried out to convert the perennial culture of the cinchona tree into an annual plant, the mass of which is used to obtain alkaloids. Cinchona bark contains crystalline alkaloids: quinine, quinidine, cinchonine, cinchonidine, homocinchonidine, hydrocinchonine, hydrocinchonidine, cinchonamine, quinamine, conquinamine, hydroquinine, hydroquinidine, chairamine, chairamidine, conchairamine, conchairamidine, aricine, cusconine, concusconine, concusconidine, dicinchonine, homoquinine, diquinidine; amorphous alkaloids: paytine, cuscamine, cuscanoidine, javanine, and others, which are still little studied, a mixture of which, obtained during the industrial extraction of quinine, forms a resinous brown mass called quinoidine; acids: quinic, quinotannic, quinovic; glycosides: alpha- and beta-quinovin; coloring substances: cinchona red, quinic red, quinovit; in insignificant quantities: sugar, wax, starch, phlobaphene, resin, lignoin, humic acids, calcium oxalate, mineral substances.

The medical use of Cinchona bark is determined not only by quinine but also by other components of Cinchona bark, such as quinotannic acid and quinic acid, which have a disinfectant and astringent effect. Wiechowski points out that some malaria patients, whose disease did not respond to treatment with quinine, recovered under the combined influence of all the components of Cinchona bark, administered internally in the form of Pulvis corticis Chinae in divided doses from 10.0 to 30.0 and up to 60.0 per day. Cinchona bark powder is given to patients as a tooth powder, relying on the mechanical, astringent, and disinfectant action of such powder. Infusum Chinae frigide paratum is used as a bitter, as a stomachic, tonic, and strengthening agent; it contains fewer active principles but is better tolerated than a hot infusion. Infusions of Cinchona bark are also used externally for washing the head. Decoctum Cinchonae acidum (7th Pharmacopoeia of the USSR) is used for mouth rinses for scurvy and for putrid softening of the gums; it can also serve for enemas. Extractum Cinchonae (7th Pharmacopoeia of the USSR) is a thick extract obtained with the help of alcohol; Extr. Chinae aquosum of thick consistency and Extr. Chinae fluidum (liquid) are used internally mostly as bitters to act as a stomachic. Tinctura Cinchonae (7th Pharmacopoeia of the USSR) and Tinctura Cinchonae composita (7th Pharmacopoeia of the USSR) are used internally in doses of 1.0–4.0 or in drops mixed with wine or mixtures as a strengthening (stomachic), tonic, and roborant agent. Tinctura Chinae composita is part of Botkin's drops (stomachic). Lit. - see lit. to the article Quinine.