Structure elucidation of three new diterpene glycosides from Stevia rebaudiana

Three new minor diterpene glycosides were isolated from the commercial extract of the leaves of Stevia rebaudiana and their structures were identified as 13-[(2-O-b-D-glucopyranosyl-b-D-glucopyranosyl)oxy] ent-kaur-15-en-19-oic acid b-D-glucopyranosyl ester (1),13-[(2-O-b-D-glucopyranosyl-3-O-b-D-glucopyranosyl-b-D-glucopyranosyl)oxy]ent-kaur-15-en-19-oic acid b-D-glucopyranosyl ester (2) and 13-[(2-O-b-D-glucopyranosyl-3-O-b-D-glucopyranosyl]- b-D-glucopyranosyl)oxy] 17-hydroxy-ent-kaur-15-en-19-oic acidb-D-glucopyranosyl ester based on extensive spectroscopic data and chemical studies.   Key words: Stevia rebaudiana, compositae, asteraceae, diterpene glycosides, structural characterization, spectral data, acid and enzymatic hydrolysis.