Minor diterpene glycosides from the leaves of Stevia rebaudiana.
J Nat Prod
; 77(5): 1231-5, 2014 May 23.
Article
em En
| MEDLINE
| ID: mdl-24758242
ABSTRACT
Two new diterpene glycosides in addition to five known glycosides have been isolated from a commercial extract of the leaves of Stevia rebaudiana. Compound 1 (rebaudioside KA) was shown to be 13-[(O-ß-d-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid 2-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl ester and compound 2, 12-α-[(2-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid ß-d-glucopyranosyl ester. Five additional known compounds were identified, rebaudioside E, rebaudioside M, rebaudioside N, rebaudioside O, and stevioside, respectively. Enzymatic hydrolysis of stevioside afforded the known ent-kaurane aglycone 13-hydroxy-ent-kaur-16-en-19-oic acid (steviol) (3). The isolated metabolite 1 possesses the ent-kaurane aglycone steviol (3), while compound 2 represents the first example of the isomeric diterpene 12-α-hydroxy-ent-kaur-16-en-19-oic acid existing as a glycoside in S. rebaudiana. The structures of the isolated metabolites 1 and 2 were determined based on comprehensive 1D- and 2D-NMR (COSY, HSQC, and HMBC) studies. A high-quality crystal of compound 3 has formed, which allowed the acquisition of X-ray diffraction data that confirmed its structure. The structural similarities between the new metabolites and the commercially available stevioside sweeteners suggest the newly isolated metabolites should be examined for their organoleptic properties. Accordingly rebaudiosides E, M, N, O, and KA have been isolated in greater than gram quantities.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Stevia
/
Diterpenos do Tipo Caurano
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Glucosídeos
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article