Phylloquinone

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Phylloquinone

 

(also vitamin K1; chemical name, 2-methyl-3-phytyl-l,4-naphthoquinone), an oil-soluble vitamin. Phylloquinone was first isolated in 1939, by P. Karrer. The vitamin is a light yellow, viscous liquid that is capable of fluorescence and is insoluble in water. Its structural formula is

Phylloquinone is synthesized in the green parts of plants and by microorganisms. In humans and other mammals, it is formed by intestinal microflora. Phylloquinone figures in the biosynthesis of certain blood-coagulation factors, namely prothrombin and factors VII, IX, and X. Like other oil-soluble vitamins, phylloquinone is a constituent of the lipids that form part of biological membranes.

A deficiency of phylloquinone in humans and animals usually derives not from an insufficiency of the vitamin in the food but rather from a disruption of the vitamin’s absorption by the walls of the intestine. The disruption can result either from disorders of the gallbladder and liver (obstructive jaundice, cirrhosis of the liver) or from overdoses of medicines that suppress intestinal microflora. Phylloquinone deficiency leads to hemorrhages and hemorrhagic diathesis, interferes with the metabolism of high-energy compounds, and lowers the activity of many enzymes. Anticoagulants of the coumarin and indandione types inhibit the biosynthesis of phylloquinone.

Phylloquinone is effective in treating those suffering from K1, hypovitaminosis. Vicasol, an analogue of vitamin K1 is used as an antihemorrhagic. In industry, phylloquinone is synthesized from 2-methyl-l,4-naphthoquinone and either phytol or isophytol.

REFERENCES

Lakin, K. M. Lekarstvennaia reguliatsiia svertyvaniia krovi. Moscow, 1971.
Berezovskii, V. M. Khimiia vitaminov, 2nd ed. Moscow, 1973.
Matusis, I. I. Vitaminy i antivitaminy. Moscow, 1975.

R. P. EVSTIGNEEVA