Structural studies on natural sweeteners by NMR spectroscopy and computational methods

Abstract

In the present day, sweet tasting molecules have attracted a lot of attention being subject of escalating sugar-related diseases. The molecular recognition of sweet tasting molecules are known to be highly dependent on their conformation, which is mostly determined by non-bonding interactions with surrounding water molecules and the sweet taste receptor. Yet, the interaction of chemoreception at the molecular level still remains undiscovered. This study aims to elucidate the hydrogen bonding properties of selected sweeteners by employing an unconventional NMR spectroscopy method. The computational studies are integrated with experiments, in order to focus on submolecular events that are assumed to be responsible for the sweet-taste recognition. Our results show distinct hydrogen bonding properties possessed by all the molecules examined. The terminal hydroxyl groups show preference to exchange protons with surrounding water molecules, while internal hydroxy protons tend to form hydrogen bonds. Experimentally observed diastereotopicity of sweet-tasting molecules shows the importance of geometry in the molecular recognition level.