180 ASCORBIC ACID 



O O 



II II 



C - 



I I 



CH2OH • CHOH— HC C=0 



\ / 



o 



Dehydroascorbic acid 

 (oxidized form) 



II. Chemistry 



FRED SMITH 



A. ISOLATION OF l-ASCORBIC ACID 



In the seventeenth century it was known that sailors at sea for long peri- 

 ods frequently developed the disease called scurvy, and as far back as the 

 middle of the eighteenth century this was traced to the fact that fresh fruit 

 and vegetables were not included in the diet. Furthermore, it was estab- 

 lished that lemon juice was an excellent remedy for the disease. At that 

 time, of course, nothing was known of accessory food factors or vitamins; 

 and little further progress took place until it was found that guinea pigs 

 were also subject to the disease of scurvy as well as man^"^ Thereafter it 

 became possible to evaluate the antiscorbutic power of various natural 

 products,^ and controlled experiments with these animals provided the nec- 

 essary means of tracing the active antiscorbutic principle during the early 

 attempts at its concentration. 



Much of the early and, consequently, the most difficult work on the con- 

 centration of the antiscorbutic factor or vitamin C was carried out by Zilva, 

 who was endeavoring to isolate the active principle from lemons.^' ^ After 

 removal of the greater proportion of extraneous material such as fiber and 

 citric acid, the active constituent was precipitated by adding basic lead 

 acetate, a procedure used today in the isolation of vitamin C from natural 

 products. The lead complex was then decomposed with hydrogen sulfide, 

 and upon evaporation of the solution there was obtained a sirupy product 

 which showed a high degree of antiscorl)utic activity. Although such con- 



1 A. Hoist, J. Hijg. 7, 619 (1907). 



2 A. Hoist and T. Frohlich, J. Hyg. 7, 634 (1907). 

 » A. Hoist and T. Frohlich, Z. Hyg. 72, 1 (1912). 



* H. Chick and E. M. Hume, Trans. Roy. Soc. Trop. Med. Hyg. 10, 141 (1916-1917); 



Proc. Roy. Soc. (London) B90, 44 (1917-1919). 

 6 A. Harden and S. S. Zilva, Biochem. J. 12, 259 (1918). 

 8 S. S. Zilva, Biochem. J. 17, 416 (1923); 18, 186 (1924); 19, 589 (1925). 



