Determine the Occurrence of vitamin K
Vitamin K is found naturally in plants and vitamin K2 is synthesized by the bacteria in the intestines in humans. In nature, only two naphthoquinone derivatives with antihaemorrhagic action - vitamins K1 and K2 have been found so far. In addition, there are a number of synthetic naphthoquinone compounds with vitamin K activity. Of these, especially vitamin K3 (menadione) and some esters of vitamin K4 (menadiol), such as 2-methyl-1,4-naphthohydroquinone dibutyrate are distinguished by valuable therapeutic properties. Other dietary sources include green leafy vegetables, cabbage, lettuce, soyabeans, beef liver and green tea. Egg yolk, milk, butter and cheese also contain vitamin K.