Sources of the Drug 141 



is pcriniticd as a substitute for C. aiitumualc in India.i^ The stand- 

 ards of the British Pharmacopoeia do not permit the use of C. luteum, 

 because the amount of colchicine in raw material is not high enough. 

 5./-/; Geographical distribution. Figure 5.1 gives the location of 

 the im])ortant" species of the genus Colcliicum, outlining the main 

 areas where species are native. Taxonomists recognize 65 species in 

 this genus,"'* but during the earlier centuries all autumn-flowering 

 species were grouped in the C. autumnaJe type. Actually, the official 

 species is distributed over Europe; line 55 outlines this area on the 

 map (Fig. 5.1) . The majority of species described on the maj) flower 

 in the fall and produce seed in the spring. Another species known to 

 antiquity is C. variegatum, number 61. The distribution of C. luteum. 

 number 1, is the easternmost representative. All are limited to the 

 Northern Hemisphere and none are reported in the Americas. 



5.2: Problems in Pharmacognosy 



Maintaining quality, protecting the consumer, preventing fraud, 

 and regulating traffic become the responsibility of trained pharma- 

 cognosists.16. 19 During earlier centuries, physicians had to use Colchi- 

 cum according to their judgment. At times this duty was a heavy 

 responsibility (cf. Chapter 1). Even today the problem is not com- 

 pletely solved, for it has been discovered that U.S. P. colchicine may 

 contain another compound, desmethylcolchicine.-^ The substance has 

 biological activity; therefore, purification of so-called pure colchicine 

 is recommended if carefully controlled experiments are to be under- 

 taken. 



The preparation of the drug from the fresh state before drying, 

 or through processes of drying, must be correct in order to avoid 

 changes in these complex conq^ounds. Colchicine in solution must 

 not be exposed to sunlight. Slicing, washing, and exposure to insects 

 or bacteria can also introduce changes. 



Four principal techniques are used to evaluate drugs. These are 

 (1) organoleptic, (2) microscopic and microchemical, (3) physico- 

 chemical, and (4) biological methods. Each particular test is de- 

 scribed in the formularies or standard works on assay of drugs. Many 

 of the methods have been applied to colchicine. 



5.3: Plants Containing Colchicine 



One species is famous in every pharmacist's handbook for the 

 jModuction of colchicine. There are )nany other species that have a 

 capacity for synthesizing the conqjound in parts of plants. All species 

 of the genus Colclncum analyzed to date yield colchicine.'''-"'^ An 

 extensive list of ihcm has been collected (Table 5.1). Two genera, 

 Merendera and Cohhicum, have been used interchangeably. Species 



