Sweet diterpenic glycosides balance of a new cultivar of Stevia rebaudiana (Bert.) Bertoni: Isolation and quantitative distribution by chromatographic, spectroscopic, and electrophoretic methods

Abstract

A dichloromethane fraction and a ultrafiltered water extract of leaves of a new cultivar of Stevia rebaudiana were submitted to separated downstreaming fractionation in silica gel columns. Non-glycosylated and glycosylated pairs for stigmasterol and β-sistosterol were obtained from the former. Stevioside and rebaudioside-A were resolved from the second hydrophilic extract. The structures of these natural compounds were then confirmed through gas chromatography coupled to mass spectrometry and hydrogen/carbon nuclear magnetic resonance. The main sweetener glycoside pair, following scaled-up water extraction, and sugar derivatives downstreaming by membrane filtration and ionic resin exchange, was analyzed by thin layer densitometered chromatography, high-pressure liquid chromatography, and capillary electrophoresis. Thus, an unusual sweetener ratio on the behalf of rebaudioside-A, a glycoside almost devoid of bitter after-taste, was found for a new Stevia cultivar (UEM-320) as compared to other native cultivars, where the bitterer stevioside was the major diterpenic glycoside.