Synthesis, Characterization, and Cellular Uptake of a Glycylglycine Chelate of Magnesium

Human chronic latent magnesium deficiency is estimated to impact a substantive portion of the world's population. A number of magnesium compounds have been developed to combat this deficiency; however, none are ideal due to issues of solubility, absorption, side effects (e.g., laxation) and/or formulation. Here, we describe the pH-dependent synthesis, chemical characterization (inductively coupled plasma and thermal analysis, infrared and nuclear magnetic resonance (1D and 2D) spectroscopies, and electrospray mass spectrometry) and in vitro uptake (in a cell model of the large intestine (CaCo-2 cells)) of a magnesium complex of the glycine dimer (HG₂). Results demonstrate that the HG₂ ligand assumes a tridentate coordination mode with an N₂O donor set and an octahedral coordination sphere completed with coordinated waters. The magnesium:HG₂ complex exhibits significant solubility and cellular uptake.