23567-23-9Relevant articles and documents
New procyanidin B3-human salivary protein complexes by mass spectrometry. Effect of salivary protein profile, tannin concentration, and time stability
Perez-Gregorio, Maria Rosa,Mateus, Nuno,De Freitas, Victor
, p. 10038 - 10045 (2014)
Several factors could influence the tannin-protein interaction such as the human salivary protein profile, the tannin tested, and the tannin/protein ratio. The goal of this study aims to study the effect of different salivas (A, B, and C) and different tannin concentrations (0.5 and 1 mg/mL) on the interaction process as well as the complex's stability over time. This study is focused on the identification of new procyanidin B3-human salivary protein complexes. Thus, 48 major B3-human salivary protein aggregates were identified regardless of the saliva and tannin concentration tested. A higher number of aggregates was found at lower tannin concentration. Moreover, the number of protein moieties involved in the aggregation process was higher when the tannin concentration was also higher. The selectivity of the different groups of proteins to bind tannin was also confirmed. It was also verified that the B3-human salivary protein complexes formed evolved over time.
Unambiguous assignments for free dimeric proanthocyanidin phenols from 2D NMR
De Bruyne, Tess,Pieters, Luc A. C.,Dommisse, Roger A.,Kolodziej, Herbert,Wray, Victor,Domke, Tobias,Vlietinck, Arnold J.
, p. 265 - 272 (1996)
Characterization of proanthocyanidin oligomers proceeds commonly through investigation of NMR data of their peracetates or methyl ether acetates, in conjunction with FAB-mass spectrometry and circular dichroism. Since such an approach is unsuitable in bioassay-guided isolations, we applied two dimensional NMR techniques for the identification of dimeric proanthocyanidins. This afforded not only a powerful probe for distinction between the different procyanidin isomers, but also allowed full assignments, even for both major rotameric forms, whenever present, without the need for derivatisation. Moreover, discrimination between the crucial 6- and 8- protons and carbons was achieved after addition of traces of cadmium nitrate, resulting in the separation of the broad phenolic signals into sharp singlets. As an example of the general strategy followed in the assignment and combination of data of the different spectra available, complete analysis of underivatised procyanidin B3 or catechin-(4α → 8)-catechin is discussed for the first time.
Molecular Interaction between Salivary Proteins and Food Tannins
Silva, Mafalda Santos,García-Estévez, Ignacio,Brand?o, Elsa,Mateus, Nuno,De Freitas, Victor,Soares, Susana
, p. 6415 - 6424 (2017/08/18)
Polyphenols interaction with salivary proteins (SP) has been related with organoleptic features such as astringency. The aim of this work was to study the interaction between some human SP and tannins through two spectroscopic techniques, fluorescence quenching, and saturation transfer difference-nuclear magnetic resonance (STD-NMR). Generally, the results showed a significant interaction between SP and both condensed tannins and ellagitannins. Herein, STD-NMR proved to be a useful tool to map tannins' epitopes of binding, while fluorescence quenching allowed one to discriminate binding affinities. Ellagitannins showed the greatest binding constants values (KSV from 20.1 to 94.1 mM-1 KA from 0.7 to 8.3 mM-1) in comparison with procyanidins (KSV from 5.4 to 40.0 mM-1 KA from 1.1 to 2.7 mM-1). In fact, punicalagin was the tannin that demonstrated the highest affinity for all three SP. Regarding SP, P-B peptide was the one with higher affinity for ellagitannins. On the other hand, cystatins showed in general the lower KSV and KA values. In the case of condensed tannins, statherin was the SP with the highest affinity, contrasting with the other two SP. Altogether, these results are evidence that the distinct SP present in the oral cavity have different abilities to interact with food tannins class.
