The interaction of lipoic acid with beta-cyclodextrin (beta-CD) has been studied by capillary electrophoresis in aqueous phosphate buffer (20 mm, pH = 9.0) at 20 degreesC, The results allowed us to detect the formation of an inclusion complex with a 1:1 lipoic acid/beta-CD stoichiometry and an association constant of 1645 M-1. The geometry of the inclusion complex in D2O was investigated by means of 2D-ROESY (Rotating-frame Overhauser Enhancement Spectroscopy) NMR experiments, which showed the occurrence of a bimodal complexation of lipoic acid inside the beta-CD cavity. Semi-empirical calculations using the PM3 method show that the orientations of the included lipoic acid are very close in energy, thus confirming the experimental observations.
Titolo: | Capillary electrophoresis, ROESY NMR and molecular modelling study of the inclusion complex beta-cyclodextrin/lipoic acid | |
Autori: | ||
Data di pubblicazione: | 2002 | |
Rivista: | ||
Abstract: | The interaction of lipoic acid with beta-cyclodextrin (beta-CD) has been studied by capillary electrophoresis in aqueous phosphate buffer (20 mm, pH = 9.0) at 20 degreesC, The results allowed us to detect the formation of an inclusion complex with a 1:1 lipoic acid/beta-CD stoichiometry and an association constant of 1645 M-1. The geometry of the inclusion complex in D2O was investigated by means of 2D-ROESY (Rotating-frame Overhauser Enhancement Spectroscopy) NMR experiments, which showed the occurrence of a bimodal complexation of lipoic acid inside the beta-CD cavity. Semi-empirical calculations using the PM3 method show that the orientations of the included lipoic acid are very close in energy, thus confirming the experimental observations. | |
Handle: | http://hdl.handle.net/11577/2467223 | |
Appare nelle tipologie: | 01.01 - Articolo in rivista |