Separation of menaquinone-7 geometric isomers by semipreparative high-performance liquid chromatography with silver complexation and identification by nuclear magnetic resonance. (30th January 2022)

• Record Type: Journal Article
• Authors: Bus, Katarzyna; Sitkowski, Jerzy; Bocian, Wojciech; Zmysłowski, Adam; Ofiara, Karol; Szterk, Arkadiusz
• Is Part Of: Food chemistry. Volume 368(2022)
• Publication Date: 2022-01-30
• Subjects: Menaquinone-7 -- Vitamin K2 -- Dietary supplement -- Geometric isomer -- Argentation chromatography -- Nuclear magnetic resonance -- Density functional theory; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2021.130890
• Languages: English
• ISSNs: 0308-8146

Abstract

Graphical abstract: Highlights: The semipreparative chromatographic method with silver complexation was developed. Theoretical calculations were used to determine energetically preferred complexes. The method was applied for isolation of 17 menaquinone-7 geometric isomers. The nuclear magnetic resonance allowed to identify 13 new components. Abstract: Dietary supplements containing vitamin K2 are often used to prevent osteoporosis, vascular calcification and coronary heart disease. It has been shown that some of these products contain a mixture of menaquinone-7 geometric isomers. Since the geometric shape may influence biological activity, there was a need for a semipreparative method to isolate single compounds for further studies. Here, we present an argentation chromatographic method for the separation of menaquinone-7 isomers and an nuclear magnetic resonance (NMR) methodology for the configuration assignment of isoprenoid side chain. The DFT calculations were performed to determine more energetically favorable complexes between the cis or trans menaquinone-7 isomers and the silver cation. Seventeen components were resolved, and fractions were collected and subjected to NMR study. Structures and chemical shifts for thirteen new compounds were assigned, and the identity of three known compounds was confirmed.