Cyclodextrins as inhibitors of the precipitation of riboflavin-5 '-phosphate due to presence of zinc chloride: A NMR investigation

Several cyclodextrins (CDs) were probed in order to counteract the precipitation of riboflavin-5' phosphate (or flavin mononucleotide, FMN-P) due to the presence of divalent cations, by exploiting Nuclear Magnetic Resonance (NMR) spectroscopy both for quantitative analyses and stereochemical characterizations. Among CDs, beta-cyclodextrin (beta-CD) showed the best solubilizing power in virtue of the formation of a 1-2 FMN-P/beta-CD complex, the stereochemistry of which was ascertained by ROESY (Rotating-frame Overhauser Enhanced SpectroscopY) measurements. (C) 2016 Published by Elsevier B.V.