Cinchona bark, quinine from

Epiquinidine, (9Ry-6 -Methoxycinchonan-9-ol a -(6-methoxy -4 -quinolyl) -5 -vinyl -2 -quinucl idinemethanol 6-melhoxy -c-(5-vinyl -2 -quinuchdinyl) -4 -qu inolinemerha -no], CjoH NPj mol wt 324.41. C 74.04%, H 7.46%. N 8.64%, O 9-86%. Occurs in cinchona bark, lsoln from qui-noidine Dtrscher], Thron, Ann. 521, 48 (1938). By epinter -ization of quinine or quinidine Rabe, Hoter. J. Prakt. 

QuinidJne. Quinidine, an alkaloid obtained from cinchona bark (Sinchona sp.), is the dextrorotatory stereoisomer of quinine [130-95-0] (see Alkaloids). The first use of quinidine for the treatment of atrial fibrillation was reported in 1918 (12). The sulfate, gluconate, and polygalacturonate salts are used in clinical practice. The dmg is given mainly by the oral (po) route, rarely by the intravenous (iv) route of adniinistration. It is the most frequentiy prescribed po antiarrhythmic agent in the United States. The clinical uses of quinidine include suppression of atrial and ventricular extrasystoles and serious ventricular arrhythmias (1 3). 

Quinine Derived from the bark of the Cinchona tree, quinine was used to treat malaria. 

At the turn of the nineteenth century, methods became available for the isolation of active principles from crude drugs. The development of chemistry made it possible to isolate and synthesize chemically pure compounds that would give reproducible biological results. In 1806, Serturner (1783-1841) isolated the first pure active principle when he purified morphine from the opium poppy. Many other chemically pure active compounds were soon obtained from crude drug preparations, including emetine by Pelletier (1788-1844) from ipecacuanha root quinine by Carentou (1795-1877) from cinchona bark strychnine by Magendie (1783-1855) from nux vomica and, in 1856, cocaine by Wohler (1800-1882) from coca. 

Quinine is a natural alkaloid obtained from cinchona bark. 

A number of naturally occurring pharmacologically active alkaloids possess quinoline and isoquinoline skeleton. For examples, papaverine from Papa-ver somniferum is an isoquinoline alkaloid and quinine from Cinchona barks is a quinoline alkaloid that has antimalarial properties. 

Cinchona and its alkaloids, particularly quinine, have been used for many years in the treatment of malaria, a disease caused by protozoa, of which the most troublesome is Plasmodium falciparum. The beneficial effects of cinchona bark were first discovered in South America in the 1630s, and the bark was then brought to Europe by Jesuit missionaries. Religious intolerance initially restricted its universal acceptance, despite the widespread occurrence of malaria in Europe and elsewhere. The name cinchona is a mis-spelling derived from Chinchon. In an often quoted tale, now historically disproved, the Spanish Countess of Chinchon, wife of the viceroy of Peru, was reputedly cured of malaria by the bark. For... 

The alkaloid quinine occurs naturally in the bark of the Cinchona tree. Apart from its continued usefulness in the treatment of malaria, it can also be taken for the relief of nocturnal leg cramps (see Chapter 22). 

Alkaloids containing quinoline as the principal nucleus include anemonine from Anemone tha-lietroides, galipine from Angostura bark (Galipea officinalis), and the cinchona alkaloids, quinine, quinidine, cinchonine, and cinchonidine (Figure 11.8). 

Quinine sulfate, the classic drug, the salt of an alkaloid obtained from cinchona bark, has been superseded by newer drugs in most parts of the world. It is only a fairly good suppressant, even in toxic dosage, and is so rapidly eliminated that it must be given at very frequent intervals to maintain its effects. When used to check an established attack, it achieves the control of parasitemia in 96 h that chloroquine accomplishes in little more than 72 h, and its effects on fever and most other symptoms also lag (Figure 22.3). 

Quinine is a naturally occurring alkaloid obtained from Cinchona bark, with a mechanism of action similar to that of chloroquine. Quinine is very useful in treating chloroquine-resistant Plasmodium falciparum. In toxic doses, it may cause cinchonism characterized by tinnitus, headache, nausea, and visual disturbances. 

Natural sources are still important sources of lead compounds and new drugs. However, the large diversity of potential natural sources in the world makes the technique of random screening a rather hit or miss process. The screening of local folk remedies (ethnopharmacology) offers the basis of a more systematic approach. In the past this has led to the discovery of many important therapeutic agents, for example, the antimalarial quinine from cinchona bark, the... 

In 1763 the use of willow tree bark was reported in more specific terms by Reverend Edward Stone in a lecture to the Royal Society in London. He used its extracts to treat the fever resulting from malaria (then common in Britain there are some marshes in the UK where the malarial mosquito still persists). He also found that it helped with the agues , probably what is now called arthritis. Other common medicines of the time included opium to relieve pain and Peruvian cinchona bark for fevers (it contained quinine). 

Although the development of trace analysis is considered to have begun with studies related to the determination of trace elements, from the pharmaceutical point of view, the beginning of this field of science should be sought in the analysis of dmgs and especially in the search for active compounds in different t3 pes of pharmaceutical decoctions, tinctures, and macerations. Isolation of opium and later morphine from poppy juice, or isolation of quinine from cinchona tree bark, were nothing other than preparation and concentration of a sample before performing trace analysis [1-3]. 

Quinine (C2oH24N202) is the most important alkaloid derived from cinchona bark. It is used as an antimalarial drug. For quinine pK = 5.1 and pKb2 = 9.7 (pKb = —log Kb). One gram of quinine will dissolve in 1900.0 mL of water. Calculate the pH of a saturated aqueous solution of quinine. Consider only the reaction Q +- H20. QH+ +- OH- described by pKb] where Q = quinine. 

Quinine (5) isolated from Cinchona bark was one of the hrst antimalarials discovered, and it became a model for the discovery and development of some of the most successful anti-malarial agents, chloroquine and its successors. However, the... 

Quinidine. Derived from cinchona bark (minor alkaloid), the anti-malarial agent quinine being a major alkaloid... 

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