Vitamin K1 (VK1)

Phylloquinone is a polycyclic aromatic ketone, based on 2-methyl-1,4-naphthoquinone, with a 3-phytyl substituent.It is a fat-soluble vitamin that is stable to air and moisture but decomposes in sunlight. It is found naturally in a wide variety of green plants.It is often called vitamin K₁ or phytonadione. Sometimes a distinction is made with phylloquinone considered natural and phytonadione considered synthetic.

A stereoisomer of phylloquinone is called vitamin k₁ .Its best known mechanism of action is as a cofactor in the formation of coagulation factors II (prothrombin), VII, IX and X by the liver. Vitamin K₁ is commonly used to treat warfarin toxicity, and an antidote for coumatetralyl. It is also required for the formation of anticoagulant factors protein C and S. Vitamin K is also required bone protein formation.