Unambiguous Determination of the Absolute Configuration of Dimeric Stilbene Glucosides from the Rhizomes of Gnetum africanum.
J Nat Prod
; 77(8): 1981-5, 2014 Aug 22.
Article
em En
| MEDLINE
| ID: mdl-25093453
ABSTRACT
Dimeric stilbene glucosides 1-3 [two diastereomers of (-)-gnemonoside A (1a and 1b), (-)-gnemonoside C (2), and (-)-gnemonoside D (3)] as well as a mixture of the two enantiomers of gnetin C (4) were isolated from the rhizomes of Gnetum africanum. The two enantiomers of gnetin C, (+)-4 and (-)-4, were obtained from the aglycones of 1a and 1b, respectively. The configurations of these stilbenoids were investigated by NMR and vibrational circular dichroism (VCD) experiments. The absolute configurations of (-)-1a, (-)-2, (-)-3, and (-)-4 were established as 7aS,8aS by VCD spectroscopy in combination with density functional theory calculations. The antiamyloidogenic activity of the isolated stilbenes was also evaluated versus beta-amyloid fibrils. The four glucosides of gnetin C (1a, 1b, 2, and 3) were found to be the most active compounds, with inhibition percentages of 56, 56, 58, and 54 at 10 µM, respectively.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Estilbenos
/
Fármacos Neuroprotetores
/
Gnetum
/
Glucosídeos
País/Região como assunto:
Africa
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article