180 



PLANT BASES 



[CH. 



Xanthine may be regarded as 2, 6-dioxypurine : 



HN— C=:0 



I I 



0=0 C— NH 



\ 

 CH 



HN— C— N 



It is widely distributed in plants and has been found in leaves of the 

 Tea plant {Thea sinensis), in the sap of the Beetroot (Beta) and in various 

 seedlings. 



Guanine and hypoxanthine can be represented respectively as 

 2-amino, 6-oxypurine and 6- nionoxy purine: 



They usually occur together and have been found in the germinating 

 seeds of the Sycamore (Acer pseudoplatanus), Pumpkin (Cucurhita 

 Pepo), Common Vetch (Vicia sativa), Meadow Clover (Trifolium 

 pratense), yellow Lupin (Lupinus luteus) and Barley (Hordeum vulgare) : 

 also in the juice of the Beet (Beta). 



Adenine is 6-aminopurine. It is represented as: 



N=C— NHo 



HC C- 



N— C- 



-NH 

 \ 



CH 



N 



It has been found in Beet (Beta), Tea leaves (Thea sinensis) and in 

 leaves of the Dutch Clover (Trifolium repens). 



Guanine and adenine are obtained by the hydrolysis of plant nucleo- 

 proteins. 



Caffeine or theine is 1, 3, 7-trimethylxanthine: 



CHgN— C=0 



II 



0=C C— N • CH, 



\ 



CH 



CH. • N— C- 



-N 



