Preparation, Stability, and Compositions of the Crystals of Reduced Riboflavins

Article abstract of DOI:10.1246/bcsj.64.1093

Green crystals were obtained after a reduction of riboflavin (RF) with Na2S2O4.These crystals were gradually oxidized to RF when stored in air, even at -10 deg C.The emission spectra and X-ray powder diffraction analyses of the green crystals clearly showed different patterns from those of RF.The ESR spectra and number of the reduced species determined by the titration with KMnO4 supported the formation of an RF-flavosemiquinone radical (1:1) complex.Reduced riboflavin tetrabutyrate prepared according to the same procedure was too unstable for dioxygen to obtain spectroscopic data.