THE LECITHINS 427 



compound from sinapine in 1852. This product is an alkaloid present in 

 white mustard seeds. Howev^er, it was a number of years l^efore this 

 latter derivative was demonstrated to be identical with choline. ^^'^ Ob- 

 viousl.y, Strecker assigned the name to choline because of his belief that it 

 was principally found in bile. 



Choline chloride was synthesized by Wurtz^*^ in 1867 by the condensa- 

 tion of trimethylamine with ethylene chlorohydrin in a sealed tube for 

 24 hours. The same worker later synthesized the free base by treating a 

 concentrated aqueous solution of trimethylamine, (CH3)3N, with ethylene 

 oxide. ^^^ These reactions are illustrated here. 



/CH3 



(CH,),N + CICHjCHgOH HOCH^CH^N-CH, 



CI ' 



Ethylene Choline 



chlorohydrhi chloride 



(CH3)3N+CHj,-CH2 ^HOCHjCHjN-CHj 



Ethylene Choline 



oxide 



Since the pioneer efforts in the isolation and characterization of choline, 

 it has been found that its distribution is widespread in both the animal 

 and the plant kingdom. In fact, it is now believed to be a component of 

 all living cells, although in many cases it may appear only in the combined 

 form. The highest concentrations are in brain, egg-yolk, liver, kidney, 

 heart, and nervous tissue, where it exists ahnost entirely in combination as 

 lecithin. A recent compilation of the choline content of foods by Hawk, 

 Oser, and Summerson^^" shows the following average amounts (in milli- 

 grams per 100 g. food): beef liver, 600; wheat germ, 400; beef kidney, 

 300; peas, 260; rice polishings, 130; beef muscle, 100; pork muscle, 100; 

 potatoes, 100; oats, 40-100; white flour, 50; whole wheat flour, 30; 

 corn, 21; milk, 15. 



The biochemical occurrence of choline has been recently summarized 

 in the monograph of Guggenheim, ^^^ as well as in the shorter reviews of 

 Alberts, ^^- and of Best and Lucas, ^^' Avhile the physiological significance 



1" A. Glaus and C. Kees^, J. prakt. Chem., 102, 24-27 (1867). 



»« A. Wurtz, Coynpt. rend., 65, 1015-1018 (1867). 



1^9 A. Wurtz, Ann., VI, suppl., 116-119, 197-202 (1868). 



"" P. B. Hawk, B. L. Oser, and ^V. H. Summerson, Practical Physiological Chemistry, 

 12th ed., Blakiston, Philadelphia, 1947, p. 1249. 



"^ M. Guggenheim, Die biogenen Amine, 3rd ed., Karger, Basel and New York. 1940, 

 pp. 102, 110, 288-289, 554. 



'" G. G. Alberts, Ergeb. inn. Med. Kinderheilk., 43, 114-148 (1932). 



"3 C. II. Rest and C. C. Lucas. Vitamins and Hormones. 1. 1-58 (1943). 



