Vitamin K2 (Menaquinone-7)

Vitamin K2 as menaquinone-7 (MK-7), CAS 2124-57-4, molecular formula C46H64O2, molecular weight 649.0, is a menaquinone carrying a seven-unit isoprenoid side chain in the all-trans (all-E) configuration. Like phylloquinone it serves as the cofactor for gamma-glutamyl carboxylase, the enzyme responsible for carboxylating vitamin K-dependent Gla proteins such as osteocalcin and matrix Gla protein. Only the all-trans isomer is biologically functional, which is why the USP monograph for Menaquinone-7 sets the assay at not less than 96.0% and not more than 101.0% of all-trans MK-7, with menaquinone-6 limited to not more than 2.0%; cis-isomer content is therefore the single most important quality parameter when comparing offers. Two routes of manufacture are supplied. Fermentation-derived MK-7 is produced by culturing Bacillus subtilis var. natto and is inherently all-trans; chemically synthesised MK-7 is also available where cost or non-soy origin is the deciding factor, and is controlled to the same isomeric limits. Pure MK-7 is a pale yellow to yellow crystalline or waxy solid melting at about 54 °C, practically insoluble in water and soluble in chloroform, ethyl acetate and methanol. Because the neat material is potent and heat-sensitive, it is traded almost entirely as standardised dilutions: 0.1%, 0.2%, 1.0% and 2.0% powders carried on microcrystalline cellulose, maltodextrin or acacia gum for tablets, capsules, sachets and gummies, and 1.0–5.0% suspensions in medium-chain triglyceride oil for softgels, drops and emulsions. Cyclodextrin-complexed and coated powder grades with improved resistance to alkaline minerals are available where MK-7 is blended alongside calcium or magnesium salts. MK-7 has been reviewed under the EU novel food framework and is the subject of FDA GRAS notifications, and buyers are supplied with the documentation needed for their own dossiers. Each lot is released with an HPLC certificate of analysis stating all-trans content, cis-isomer and MK-6 levels, appearance, loss on drying, particle size, residual solvents, heavy metals and microbiology, together with MSDS, non-GMO, allergen, halal and kosher declarations where the grade permits. Material is protected from light and oxygen throughout filling and export packing.