NMR Spectral Analysis and Hydrolysis Studies of Rebaudioside N, a Minor Steviol Glycoside of <i>Stevia rebaudiana</i> Bertoni

Abstract

The complete proton and carbon NMR spectral assignments of a diterpene glycoside isolated from the commercial extract of the leaves of Stevia rebaudiana Bertoni, 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] entkaur-16-en-19-oic acid-[(2-O-α-L-rhamnopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl) ester] (1); also known as rebaudioside N, was achieved by the extensive 1D and 2D NMR (1H and 13C, COSY, HMQC, HMBC) as well as mass spectral data. Further, hydrolysis studies were performed on rebaudioside N using acid and enzymatic studies to identify aglycone and sugar residues in its structure.