Phylloquinone vitamin Ki

Radical pairs of phylloquinone (vitamin Ki) were produced by reaction with A1C13 or by photochemical reaction at 77 K.40 The dipolar splitting (D) of 19 0.5 mT for the photochemically produced radical pair corresponds to a point dipole distance of 5.3 A, which is attributed to a solvent-separated radical pair. For radical pairs generated with A1C13, D --= 11.2 + 0.5 mT (r = 6.3 A), which is consistent with the distance between two phylloquinone radicals coordinated to an Al3+ ion.40... 

Haroon, Y., Shearer, M.J., Rahim, S., Gunn, W.G., McEnery, G., Barkhan, P. 1982. The content of phylloquinone (vitamin Ki) in human milk, cow s milk and infant formula foods determined by high-performance liquid chromatography. J. Nutr., 112, 1105-1117. 

Bolton-Smith CPR, Fenton ST, Harrington DJ, and Shearer MJ (2000) Compilation of a provisional UK database for the phylloquinone (vitamin Ki) content of foods. British Journal of Nutrition 83, 389-99. 

Ergocalciferol (vitamin D2) Cholecalciferol (vitamin D3) n-Tocopherol (vitamin E) a-Tocopherol acetate Phylloquinone (vitamin Ki)... 

Figure 16.10 Biosynthesis of phylloquinone (vitamin Ki) from 1,4-dihydroxynaphthoic acid. The key step that joins the 20-carbon phytyl side chain to the aromatic ring is a Friedel-Crafts-like electrophilic substitution reaction.

Chemical structure (Figure 5). Derivatives of naphthoquinone natural forms contain an unsaturated isoprenoid side chain on C-3 parent compound 2-methyl-1,4-naphthoquinone (menadione, not thought to occur naturally) green plants contain 2-methyl-3-phytyl-l,4-naphthoquinone (phylloquinone, vitamin Ki) with one double bond in the side chain. 

Phylloquinone (vitamin Ki(20)) and also the other K-vitamers are destroyed in alkaline medium and isomerize in daylight. They are easily reduced but are fairly stable toward oxidizing conditions and heat. 

The major source is phylloquinone (vitamin Ki) found in vegetable oils and green leafy vegetables. Menaquinone (vitamin K2) is synthesised by the flora of the large intestine. 

Fig. 4. Branched biosynthetic pathways leading to phylloquinone (Vitamin Ki) and anthraquinones (e.g. lucidinprim-veroside).

MONEGER. 1984. Prenylation and methylation reactions in phylloquinone (vitamin Ki) synthesis in Capsicum annuum plastids. Plant Cell Rep. 3 240-242. 

Figure 8 Thin-layer chromatography of prenylquinones and prenols. Adsorption chromatography on (A) silica gel plates, solvent light petroleum-diethyl ether (9 1), and (B) on silica gel plates impregnated with AgN03, solvent light petroleum-chloroform-acetone (50 10 17) Ki, phylloquinone, vitamin Ki MKa, menaquinone-4 PQ-9, plastoquinone-9 Q-9 and Q-10, ubiquinone-9 and -10 a-T, a-tocopherol a-Ts, a-tocotrienol 3-C, P-carotene GG, geranyl-geraniol (Source From Ref. 18, with permission of the copyright owner).

Y Haroon, DS Bacon, JA Sadowski. Chemical reduction system for the detection of phylloquinone (vitamin Ki) and menaquinones (vitamin K2). J Chromatogr 384 383-389, 1987. 

M Careri, A Mangia, P Manini, N Taboni. Determination of phylloquinone (vitamin Ki) by high performance liquid chromatography with UV detection and with particle beam-mass spectrometry. Fresenius J Anal Chem 355 48-56, 1996. 

The K homologues [1] are a family of 2-methyl-l,4-naphthoquinones possessing cofactor activity for y-glutamylcarboxylase and differ in the side chain attached at C3. Phylloquinone (vitamin Ki) has a phytyl side chain and occurs in green plants. Vitamin K2 includes a group of compounds s)mthesized by bacteria and characterized by a polyisoprene side chain each of them is designated menaquinone-n (MK-n, with n from 4 to 13) according to the number of isoprenyl units. Menadione (vitamin K3), menadiol (vitamin K4), and vitamin Ki(2s) are synthetic forms [1,4]. 

Booth SL, Davidson KW, Sadowski JA. Evaluation of an HPLC method for the determination of phylloquinone (vitamin Ki) in various food matrices. J Agri Food Chem 1994 42 295-300. 

Separation of tocopherols from other fat-soluble vitamins. a-Tocopherol can be readily resolved by TLC on silica gel or alununa from other fat-soluble vitamins (61). On silica gel, it migrates ahead of the D vitamins but more slowly than retinol (vitamin A) and phylloquinone (vitamin Ki). The differentiation of the free tocopherol and its acetate and succinate esters, which are frequently used in pharmaceutical preparations, is also straightforward (61). 

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