UNIGE document Scientific Article
previous document  unige:10820  next document
add to browser collection
Title

On-line identification of unstable iridoids from Jamesbrittenia fodina by HPLC-MS and HPLC-NMR

Authors
Cogne, A.-L.
Queiroz, E. F.
Marston, Andrew
Mavi, S.
Published in Phytochemical Analysis. 2005, vol. 16, no. 6, p. 429 - 439
Abstract HPLC-UV-MS analysis of the methanol extract of Jamesbrittenia fodina (Wild) O. M. Hilliard (Scrophulariaceae) revealed the presence of different iridoid cinnamic esters; however, isolation of these constituents was prevented by instability problems. HPLC-UV-MS and HPLC-NMR analysis of the mixtures obtained after a tentative isolation indicated that, in the first instance, instability was due to a light-induced cisltrans isomerisation of the cinnamic moieties. Further investigation of related compounds showed an additional instability problem linked to other chemical transformations. A detailed HPLC-NMR-MS study of these fractions demonstrated that the modifications occurred on the rhamnose moiety of these iridoids. It could be concluded that the second type of instability was attributable to transesterification of the cinnamic moiety on the rhamnose unit. The recording of stop-flow HPLC-NMR spectra for specific HPLC peaks permitted the direct monitoring of these transformations. Based on these on-line data, six new unstable aucubin derivatives were efficiently characterised.
Keywords HPLC-NMRHPLC-MSIridoidsAucubin derivativesTrans-acylationJamesbrittenia fodinaScrophulariaceae
Stable URL http://archive-ouverte.unige.ch/unige:10820
Full text
Article (Published version) (315 Kb) - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://doi.wiley.com/10.1002/pca.866
Identifiers
Structures
129 hits and 1 download since 2010-08-24
Update
Export document
Format :
Citation style :