754 XII. VITAMINS K 



o 



H II 



C C 



/• \ / \ 

 HC C CCH3 CH3 CHs 



I II II J. i 



HC C CCHoCH=(CCHoCHoCH=)5CCH3 



V \^ 



Vitamin K2 

 (2-Methyl-3-difarnesyl-l,4-naphthoquinone) 



O 



g h 



/• \ / \ 

 HC C CCH3 



HC C CH 



\- / \ / 



c c 



H II 



o 



Menadione 

 (2-I\Ieth3-l-l,4-naphthoquinone) 



2. The Occurrence of the Vitamins K 



(1) Occurrence in Plants 



The chief natural sources of vitamin Ki are the green leafy plants such as 

 alfalfa, ^'•■^''■'*'' spinach,-^''"' cabbage,^'^''"'*" kale, cauliflower, nettle, and 

 chestnut leaves.^ The inner leaves of the cabbage have been shown to 

 have only about one-fourth of the vitamin K content of the outer leaves.** 

 The tops of carrots are a good source of this vitamin, but very little is 

 present in the roots. ^ Dam and Glavind^'' noted the presence of vitamin K 

 in tomatoes, hempseed, and seaweed, while Almquist and Stokstad^^ found 

 that it was a component of soybean oil. More vitamin K occurs in peas 

 sprouted in the light than in those kept in the dark.*" According to 

 Shinowara et al.,*'^ the berries of the European mountain ash (Sorhus 

 aucuparia, L.) are good sources of the vitamin. Vitamin K has also 

 been found as a component of oat shoots, and to a limited extent in 



39 A. J. Quick, Am. J. Physiol., 118, 260-271 (1937). 

 « H. Dam and J. Glavind, Biochem., J., 32, 485-487 (1938). 

 ^1 H. J. Almquist and E. L. R. Stokstad, /. Nutrition, I4, 235-240 (1937). 

 ^2 G. Y. Shinowara, J. C. DeLor, and J. W. Means, ./. Lab. Clin. Med., 27, 897-907 

 (1942). 



I 



