Characterization of the fraction components using 1D TOCSY and 1D ROESY experiments. Four new spirostane saponins from Agave brittoniana Trel. spp. Brachypus.
A careful NMR analysis, especially 1D TOCSY and 1D ROESY, of two refined saponin fractions allowed us to determine the structures of four new saponins from a polar extract of the Agave brittoniana Trel. spp. Brachypus leaves. A full assignment of the 1H and 13C spectral data for these new saponins, agabrittonosides A-D (1-4), and one previously known saponin, karatavioside A (5) is reported. Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, ROESY, g-HSQC, g-HMBC and g-HSQC-TOCSY) NMR techniques and ESI-MS. Moreover, the work represents a new approach to structural elucidation of saponins in refined fractions by NMR investigations.
Macías
Francisco A
FA
Grupo de Alelopatía, Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, C/República Saharaui, s/n, 11510 Puerto Real, Cádiz, Spain. famacias@uca.es
Guerra
José O
JO
Simonet
Ana M
AM
Nogueiras
Clara M
CM
D027882:Agave / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification; D013150:Spirostans / Q000737:chemistry* / Q000302:isolation & purification
D010936:Plant Extracts; D012503:Saponins; D013150:Spirostans