48 THE SIMPLER NATURAL BASES 



fore to some extent more akin to the alkaloids. As it is however very 

 similar to stachydrine, and as it has moreover been found in a number 

 of species belonging to widely different natural orders, its inclusion 

 here may be justified. Trigonelline was discovered by Jahns [1885] 

 in the seeds of Trigonella foenum graecum (the Fenu greek). It has 

 also been obtained from the seeds and seedlings of Pisum sativum 

 (Schulze and Winterstein [1910]) ; from the seeds of Phaseolus vulgaris, 

 Cannabis sativa, Avena sativa (Schulze [1896 ; Ch. IV, choline], Stro- 

 phanthus hispidus, and 5. Kombe, Thorns [1898, I, 2 ; Ch. IV, choline] 

 and Coffea arabica, Polstorff [1909, 2; Ch. IV, choline]); from the 

 tubers of Stachys tuberifera and from potatoes (Schulze [1904 ; Ch. IV, 

 choline]); from the roots of Scorzonera hispanica and the tubers of 

 Dahlia (Schulze and Trier [1912, I ; section on betaine]). It is generally 

 present in very small quantity and will doubtless be found to occur in 

 many more species. 



Nicotinic acid, from which trigonelline is formed by methylation, 

 occurs in rice polishings (Suzuki, Shimamura and Odake [1912], 

 Funk [1913] ; both references in Ch. VII, vitamine, oryzanin). When 

 this acid is given to dogs, trigonelline appears in the urine (Acker- 

 mann [1912, l]). 



The constitution of trigonelline was established by Jahns [1887]. 

 CH CH 



CH/^j C . CO CH/^C . COOH 



CH" ^'CH * CH^JCH 



N O N 



^ 3 



On heating with concentrated hydrochloric acid to 270 nicotinic (/?- 

 pyridine-carboxylic) acid was formed and trigonelline was shown to be 

 identical with the " methylbetain " of nicotinic acid, previously synthe- 

 sised by Hantzsch [1886]. 



Trigonelline is physiologically inert; given subcutaneously, O'I2 

 grm. had no effect on frogs, nor O'5 grm. on rabbits (Jahns [1887]; 

 compare also Kohlrausch [1909, 1911; section on betaine]). The 

 methylation of nicotinic acid to trigonelline in the dog, discovered by 

 Ackermann [1912, i], is similar to the methylation of pyridine to 

 methylpyridinium hydroxide (see the next section). 



Other Pyridine Bases. 



Although they are not betaines, other derivatives of pyridine may be referred to here. 

 For pyridine derivatives formed in putrefaction see Chapter I, p. 17. 



His [1887] showed that when pyridine acetate is given by the mouth to dogs, about 

 one quarter may be recovered from the urine as the quaternary base, methyl -pyridinium 

 hydroxide. 



