410 THIAMINE 



the Vitab Corporation in Emeryville, California, with an activity up to 50 

 units per milliliter. Colman^ and Arnold and Schreffler-^ improved the ex- 

 traction and the taste of the preparation. It is still used today: U. S. 

 Pharmacopeia XIV (1950, p. 515) describes the extract with 0.06 mg. of 

 Bi per millihter. 



2. Low Concentrates from Yeast 



By plasmolysis of yeast, coagulation of the protein material and con- 

 centration of the aqueous solution Light and Frey* developed a method of 

 preparing yeast concentrates with a thiamine content up to 300 units per 

 gram. 



3. High Concentrates from Rice Germs 



A highly improved method for isolating crystalline thiamine from rice 

 polish was published in May 1934 by Williams et al.^ By using a richer source 

 than rice bran or polish, namely rice germs, F. Hoffmann-La Roche Ltd. 

 in Basle, Switzerland (F. Elger, A. J. Frey, and H. M. Wuest) developed a 

 method yielding concentrates with 25,000 to 30,000 units per gram. This 

 product was used in 1935-1937 for the multivitamin preparation Nestrovit 

 (vitamins A, Bi, C, and D in a basis of dried skimmed milk, sugar, and 

 cocoa butter); 1200 to 1500 kg. of rice germs were worked up daily. 



4. Isolation of Crystalline Thiamine from Natural Sources 



The isolation of crystalline thiamine by Jansen and Donath^, by Windaus 

 et al.,'' and by Williams et al} are today only of historical interest. Williams^ 

 gives a good characterization of the efforts in his book: "It is doubtful 

 whether the isolation and identification of any other substance in the 

 history of biochemistry have cost as much labor as have these operations 

 as applied to thiamin. The first gram of the pure vitamin must have cost an 

 aggregate of several hundred thousand dollars" (written in 1938). 



In spite of the improvements of the methods ^'■'^ pure natural thiamine 



2H. B. Coleman. U.S. Pat. 2,369,775 (February 20, 1945). 



3 A. Arnold and C. B. Schreffler, U.S. Pat. 2,390,679 (Deceml)er 11, 1945). 



* R. F. Light and C. N. Frey, U.S. Pat. 2,184,748 (December 26, 1939); British Pat. 

 428,044 (April 30, 1935). 



s R. R. Williams, R. E. Waterman, and J. C. Keresztesy, J. Am. Chem. Soc. 56, 1187. 



1189 (1934); U.S. Pat. 2,049,988 (August 4, 1936). 

 ^ B. C. P. Jansen and W. F. Donath, Proc. Koninkl. Akad. Wetenschap. Amsterdam 



29, 1390 (1926); Mededeel. Diensl Voll-sgezondheid, Ned. -Indie 16, 186 (1926). 

 ' A. Windaus, R. Tschesche, H. Ruhkopf, F. Laquer, and F. Schultz, Nachr. Gc\^. 



Wiss. Gottingen III p. 207 (1932). 



* R. R. Williams, and T. D. Spies, Vitamin Bi (Thiamin) and Its Use in Medicine 

 p. 138. The Macmillan Co., New York, 1938. 



9 A. Seidell, /. Biol. Chem. 82, 633 (1929). 



