Identification of natural epimeric flavanone glycosides by NMR spectroscopy

Recently advanced analytical technology has provided evidence of the existence of stereoisomers of many natural products. Particularly, flavanones which might have two different configurations at C-2 exist in many food additives, e.g., citrus fruits. In this study, the possible stereoisomers of flavanone glycosides were identified by NMR spectroscopy. Based on NMR spectra of common flavanone glycosides such as naringin, hesperidin, and neohesperidin, the two existing diastereomeric forms of the molecules could clearly be distinguished. The 1H NMR resonances of two diastereomers of each flavanone glycosides investigated in this study were fully assigned with the assistance of diverse 2D NMR spectroscopy methods.