D’Amelio, N;
Papamokos, G;
Dreyer, J;
Carloni, P;
Navarini, L;
(2015)
NMR Studies of Hetero-Association of Caffeine with di-O-Caffeoylquinic Acid Isomers in Aqueous Solution.
Food Biophysics
, 10
(3)
pp. 235-243.
10.1007/s11483-014-9368-x.
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Abstract
Caffeine hetero-association with 3,5-di-O-caffeoylquinic acid, 3,4-di-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid in aqueous solution has been investigated by one-dimensional (1D) and two-dimensional (2D) high resolution 1H and 13C NMR spectroscopy. Self-association of the di-O-caffeoylquinic acid isomers has been studied as well. Caffeine-di-O-caffeoylquinic acid isomers association constants were measured. The value of the association constant of the caffeine-di-O-caffeoylquinic acid complexes is compatible with previous studies and within the typical range of reported association constants for other caffeine-polyphenols complexes. Structural features of the three different complexes have also been investigated by NMR spectroscopy combined with quantum chemical calculations, and the complex conformation is discussed. Our results show that stacking interactions drive the formation of the complexes and that multiple equilibria are present in the interaction of caffeine with 3,4-di-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid while the complex with 3,5-di-O-caffeoylquinic acid seems to be better defined.
Type: | Article |
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Title: | NMR Studies of Hetero-Association of Caffeine with di-O-Caffeoylquinic Acid Isomers in Aqueous Solution |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1007/s11483-014-9368-x |
Publisher version: | http://dx.doi.org/10.1007/s11483-014-9368-x |
Language: | English |
Additional information: | © The Author(s) 2014 Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. |
Keywords: | Caffeine, Di-O-caffeoylquinic acid isomers, NMR Caffeine, heteroassociation, Density functional theory |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences |
URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1470733 |
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