166 THE PLANT BASES 



Theobromine is 3, 7-dimethylxanthine: 



HN— C--0 



I I 

 0=C C— NCH, 



^ 



[CH. 



CHs-N— C— N 



It occurs in the fruit of the Cocoa plant {Theohroma Cacao), in 

 leaves of the Tea plant {Thea sinensis) and in the Kola nut {Cola 

 acuminata). 



Guanine and hypoxanthine can be represented respectively as 

 2-aniino, 6-oxypurine and 6-monoxypurine: 



HN— C^O HN— C=0 



I 1 



H,N— C C— NH 



^ 



N— C— N 



Guanine 



HC C— NH 



CH 



N— C— N 



Hypoxanthine 



They usually occur together and have been found in the germinating 

 seeds of the Sycamore {Acer pseiidoplatanus), Pumpkin {Cticurbita 

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

 pratense), yellow Lupin {Lupinus luteus) and Barley {Hordeum vidgare): 

 also in the juice of the Beet {Beta). 



Adenine is 6-aminopurine. It is represented as: 



N=c— NH2 



I I 

 HC C— NH 



CH 



-N 



It has been found in Beet {Beta), Tea leaves {Thea si^wnsis) and in 

 leaves of the Dutch Clover {Trifolium repens). 



Guanine, hypoxanthine and adenine are all obtained by the hydro- 

 lysis of plant nucleoproteins. 



