CINCHONA 267 



hydrocinchonidine, quinamine, and homocinchonidine. (For a com- 

 plete list see Henry, c Plant Alkaloids,' 1913, p. 130.) 



In addition to the alkaloids, many cinchona barks also contain 

 a very bitter amorphous glucoside, quinovin ; a crystalline organic 

 acid, quinic or kinic acid, also found in coffee, in the whortleberry 

 (Vaccinium Myrtillus, Linne), and other plants ; a particular tannin, 

 cinchotannic acid, which by oxidation rapidly yields a dark-coloured 

 phlobaphene, cinchona red ; starch, calcium oxalate, &c. 



The amount of total alkaloid present in cinchona barks is subject 

 to great variation. Quilled red bark from India averages about 

 6-5 per cent. ; that from Java is richer, yielding about 8'25 per cent. 

 Calisaya quills afford about 6 or 7 per cent, and pale bark about 6 per 

 cent. Ledger bark from Java is the richest of all, yielding from 

 5 to 10 or even more per cent, of total alkaloid. Root-bark is the 

 richest, and stem-bark is better than branch-bark. The relative 

 value of a bark is, however, determined by the proportion of 

 quinine it contains. 



Quinine was first isolated by Pelletier and Caventou in 1820, after 

 Gomez in 1811 had produced from cinchona a crystalline combination 

 of quinine and cinchonine. It occurs in the largest proportion in 

 Ledger bark, the highest recorded yield being 14-5 per cent. 

 This, however, is quite exceptional, the quinine in commercial 

 Ledger bark averaging from 3'0 to 8'0 per cent. Bolivian cultivated 

 calisaya contains from 3'0 to 4'0, and cultivated C. officinalis about 

 3*0 per cent. Indian red bark contains about 1*5 per cent, of quinine, 

 but that from Java is richer, attaining as much as 5 per cent. 



Cinchonine is found in small quantity in most of the cinchona 

 barks, especially O. lancifolia and some specimens of G. succirubra, 

 this alkaloid is frequently more abundant in the root-bark than in 

 the stem-bark. 



Quinidine, discovered by Henry and Delondre in 1833, seldom 

 exceeds 0*5 per cent, in any bark ; it occurs chiefly in certain varieties 

 of G. Calisaya. 



Cinchonidine, isolated in 1847 by Winckler, is found more generally 

 distributed and in much larger proportion than quinidine. The 

 cultivated G. succirubra at present exported from India contains as 

 a rule more cinchonidine than quinine, from 3 to 4 per cent, being 

 frequently present. 



All these alkaloids exist, according to de Vrij, combined with 

 cinchotannic acid in the parenchymatous tissue of the bark. 



Uses. The cinchona barks are far too bulky for use as antiperiodics 

 and antipyretics if quinine can be obtained. They are therefore 

 given only as bitter stomachics and tonics. The amount of tannin 

 contained in them indicates that they may be used when an astringent 

 effect also is desired. 



