# Discovery of Novel Minor Steviol Glycoside from the Stevia rebaudiana: Structural Characterization and Proposed Biosynthetic Pathway of Rebaudioside D17

## TL;DR

A new steviol glycoside, Rebaudioside D17, was discovered in Stevia leaves, offering insights into natural sweetener diversity and biosynthesis.

## Contribution

The discovery of Rebaudioside D17 and its unique β-1→4 glycosidic linkage expands the structural diversity of steviol glycosides.

## Key findings

- Rebaudioside D17 was isolated and characterized using advanced NMR and mass spectrometry techniques.
- A proposed biosynthetic pathway links Rebaudioside D17 to Rebaudioside E19 and Rebaudioside U3.
- The compound's unique glycosidic linkage suggests new possibilities for sweetener development.

## Abstract

A novel steviol glycoside, Rebaudioside D17, was identified from the leaf extract of Stevia rebaudiana Bertoni. This compound features a rare β-1→4 glycosidic linkage between two glucose units at the C19 position, distinguishing it from its structural isomer, Rebaudioside D. The aim of this study was to isolate and characterize Rebaudioside D17 and investigate its biosynthetic origin. The compound was isolated and structurally characterized using comprehensive NMR spectroscopy including 1H, 13C, COSY, NOESY, Heteronuclear Single Quantum Coherence–Distortionless Enhancement by Polarization Transfer (HSQC-DEPT), Heteronuclear Multiple Bond Correlation (HMBC), Heteronuclear Single Quantum Coherence–Total Correlated Spectroscopy (HSQC-TOCSY), along with mass spectrometry analysis. A tentative biosynthetic pathway is proposed, involving Rebaudioside E19, a putative intermediate bearing the same β-1→4 glycosidic linkage at C19. Rebaudioside E19 may serve as a common precursor to both Rebaudioside D17 and Rebaudioside U3, a minor steviol glycoside previously reported in Stevia rebaudiana leaf extract, which also contains the same β-1→4 glycosidic linkage. The discovery of Rebaudioside D17 expands the known diversity of steviol glycosides and provides new insights into glycosylation patterns in Stevia rebaudiana, which may support the development and production of novel sweeteners with improved sensory and physicochemical properties.