Novel enzymatic elimination method for the chromatographic purification of ginsenoside Rb(3) in an isomeric mixture

BACKGROUND: The separation of isomeric compounds from a mixture is a recurring problem in chemistry and phytochemistry research. The purification of pharmacologically active ginsenoside Rb(3) from ginseng extracts is limited by the co-existence of its isomer Rb(2). The aim of the present study was to develop an enzymatic elimination-combined purification method to obtain pure Rb(3) from a mixture of isomers. METHODS: To isolate Rb(3) from the isomeric mixture, a simple enzymatic selective elimination method was used. A ginsenoside-transforming glycoside hydrolase (Bgp2) was employed to selectively hydrolyze Rb(2) into ginsenoside Rd. Ginsenoside Rb(3) was then efficiently separated from the mixture using a traditional chromatographic method. RESULTS: Chromatographic purification of Rb(3) was achieved using this novel enzymatic elimination-combined method, with 58.6-times higher yield and 13.1% less time than those of the traditional chromatographic method, with a lower minimum column length for purification. The novelty of this study was the use of a recombinant glycosidase for the selective elimination of the isomer. The isolated ginsenoside Rb(3) can be used in further pharmaceutical studies. CONCLUSIONS: Herein, we demonstrated a novel enzymatic elimination-combined purification method for the chromatographic purification of ginsenoside Rb(3). This method can also be applied to purify other isomeric glycoconjugates in mixtures.