214 



ALKALOIDS 



Morphine, C 17 H 19 N0 3 . 

 Strychnine, C.^H.^NoO,. 

 Quinine, C 20 H 24 CO,: 

 Caffeine or Theine, C 8 H 10 N 4 O,. 



(Trimethyl xanthine, 1.3.7). 

 Theobromine, C 7 H 8 N 4 O 2 . 



(Dimethyl xanthme, 3.7). 



The two latter compounds are important constituents of certain 

 plants tea, mate, coffee and cocoa. They are intimately related 

 in chemical constitution with xanthine, C 5 H 4 N 4 O 2 , found in many 

 animal products and in certain plants ; with guanine, C r) H 5 N 5 O, found 

 in guano and with uric acid, C 5 H 4 N 4 O 3 . The following formulae will 

 illustrate the connection : 



HN CO HN CO 



II II 



OC C NH HN=C C NH 



i ii > co 



HN C NH 



Uric acid. 



HN CO 

 OC C NH 



:CH 



HN- 



HN C N 



Xanthine. 



[ C N 



Guanine. 



HN CO 



OC C N.CH 3 

 ^CH 

 CH a .N C N 



Theobromine. 



CH 3 .N CO 



CH 3 .N 



Theine or Caffeine. 



', The functions of the alkaloids in plants is not known ; as food- 

 stuffs they have no value, but their therapeutic effect is often of great 

 importance. 



(iv) The Cyanogenetic Glucosides. More than a hundred 

 species of plants have been found to contain compounds which readily 

 evolve hydrocyanic acid when distilled with water. In many cases, it 

 has been shown that this is due to the presence in the plant of com- 

 pounds containing glucose, some other organic radicle and hydrocya- 

 nic acid and that the latter is liberated when the compounds are 

 hydrolysed by acids or by enzymes. 



The best known of these cyanogenetic glucosides are 

 Amygdalin, a substance found in bitter almonds and in the seeds 

 of many other plants. This has been proved to undergo the following 

 changes on hydrolysis : 



