RQ3, A Natural Rebaudioside D Isomer, Was Obtained from Glucosylation of Rebaudioside A Catalyzed by the CGTase Toruzyme 3.0 L

Qingbin Guo; Tongtong Zhang; Nifei Wang; Yongmei Xia; Zhuoyu Zhou; Jian-Rong Wang; Xuefeng Mei

doi:10.1021/acs.jafc.9b02545

RQ3, A Natural Rebaudioside D Isomer, Was Obtained from Glucosylation of Rebaudioside A Catalyzed by the CGTase Toruzyme 3.0 L

J Agric Food Chem. 2019 Jul 17;67(28):8020-8028. doi: 10.1021/acs.jafc.9b02545. Epub 2019 Jul 1.

Authors

Qingbin Guo^{1

2}, Tongtong Zhang^{1

3}, Nifei Wang², Yongmei Xia^{1

3}, Zhuoyu Zhou^{1

3}, Jian-Rong Wang⁴, Xuefeng Mei⁴

Affiliations

¹ State Key Laboratory of Food Science and Technology , Jiangnan University , Wuxi , Jiangsu 214122 , China.
² State Key Laboratory of Food Nutrition and Safety , Tianjin University of Science and Technology, Ministry of Education , Tianjin 300457 , China.
³ School of Chemical and Materials Engineering , Jiangnan University , Wuxi , Jiangsu 214122 , China.
⁴ Pharmaceutical Analytical & Solid-State Chemistry Research Center, Shanghai Institute of Materia Medical , Chinese Academy of Sciences , Shanghai 201203 , China.

PMID: 31259548
DOI: 10.1021/acs.jafc.9b02545

Abstract

In this study, a monoglucosyl rebaudioside A product was isolated from the mixture of glucosylated rebaudioside A obtained from the most reported and industrial used cyclodextrin glycosyl transferase, Toruzyme 3.0 L (CGTase, Toruzyme 3.0 L). The molecular structure of the monoglucosyl rebaudioside A was characterized using LC-MS/MS and methylation analysis combined with 1D and 2D NMR, indicating that it is 13-[(2-O-(3-α-O-D-glucopyranosyl)-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-D-glucopyranosyl ester (also known as RQ3, which naturally exists in Stevia extract as an isomer of rebaudioside D). This study may help to further understand the reaction mechanism of glucosylation of steviol glycoside assisted by Toruzyme 3.0 L in the aspect of molecule linkage pattern, and also benefit the application of the glucosylated rebaudiosides.

Keywords: NMR; glycosylation; rebaudioside; steviol glycoside; transglucosylation.

MeSH terms

Biocatalysis
Diterpenes, Kaurane / chemistry*
Glucosyltransferases / chemistry*
Glycosides / chemistry*
Glycosylation
Isomerism
Molecular Structure
Tandem Mass Spectrometry

Substances

Diterpenes, Kaurane
Glycosides
rebaudioside D
rebaudioside A
Glucosyltransferases
cyclomaltodextrin glucanotransferase