TERPENOIDS 



257 



=0 



cardenolid 



Some other compounds in this class are digitoxigenin, uzari- 

 genin, xysmalogenin, canarygenin, adynerigenin, and their glycosides. 

 Korte and Korte (1955b) have studied the distribution of these com- 

 pounds, certain related alkaloids, and lower terpenes in the order 

 Contortae with some exceedingly interesting results. Within the order 

 the family Gentianaceae is consistent in having the terpene, gentio- 

 pikrin, present in all forms examined. 



OH 



O + glucose 



gentiopikrin 



The family Menyanthaceae (sometimes classified as a sub- 

 family of the Gentianaceae) are separated from the Gentianaceae by 

 the presence of the bitter principle loganin ( = meliatin) in the former 

 and the absence of gentiopicrin in those members of the Menyan- 

 thaceae examined. 



O 



HOH2C c 



.CH-CH C=CHCH3 



H3COOC 



H2C CHOH 



loganin 



Both families include some species which produce the 

 alkaloid, gentianin [note that Karrer (1958) lists gentianin both as an 

 anthocyanin and as a xanthone, neither compound containing nitro- 

 gen] the structure of which is given below: 



CH=CH2 



Since the Menyanthaceae share a characteristic component 

 of the Loganiaceae, namely, loganin, it may be deduced from these 



