Development of a Competition Assay for the Evaluation of the Binding of Human Parotid Salivary Proteins to Dietary Complex Phenols and Tannins Using a Peroxidase-Labeled Tannin

Abstract

Proline-rich proteins (PRP) are secreted by herbivores, including humans, in their parotid saliva into the oral cavity. These PRP have a high affinity for dietary complex phenols and tannins (CPT). The stable complexes formed may then pass through the digestive tract and are excreted. It is postulated that such complexes may modulate both the antinutritional effects and beneficial properties of CPTs. A novel competitive tannin−salivary protein binding assay is described that allows the detailed investigation of binding of tannins to salivary proteins. The assay is based on the competition between an enzyme-labeled tannin [(−)-epigallocatechin conjugated to horseradish peroxidase via a linker molecule] and a test tannin to bind to parotid salivary protein immobilized in the wells of a polystyrene microtiter plate. The binding affinities of a series of flavan-3-ol monomers from tea and a commercial tannic acid preparation were determined. Major differences in the binding affinities of the compounds tested to the salivary proteins were observed. A relationship between the level of tannin galloylation and the affinity of binding to parotid salivary protein is demonstrated. Keywords: Proline-rich proteins; parotid saliva; polyphenol complexation; tannin; flavan-3-ol

Activity, Purification, and Analysis of Condensed Tannins: Current State of Affairs and Future Endeavors

“…2) and flavan-3-ol subunits of CTs increases their ability to bind to and precipitate proteins (Ricardo-da-Silva et al, 1991: Bacon andRhodes, 1998;de Freitas and Mateus, 2001) over their non-galloylated counterparts. 2) and flavan-3-ol subunits of CTs increases their ability to bind to and precipitate proteins (Ricardo-da-Silva et al, 1991: Bacon andRhodes, 1998;de Freitas and Mateus, 2001) over their non-galloylated counterparts.…”

Sorghum phytochemicals and their potential impact on human health

“…Inhibition of intestinal brush-border bound amino acid transporters by sorghum tannins was also reported . There is evidence that the higher DP tannins are more involved in these interactions that the low DP ones (Bacon and Rhodes, 1998;Sarni-Manchado et al, 1999).…”

Prediction of perceived astringency induced by phenolic compounds II: Criteria for panel selection and preliminary application on wine samples

“…The reactivity of polyphenols with proteins has often been used for this purpose (Bacon & Rhodes, 1998;Carvalho, Mateus, & de Freitas, 2004;Edelmann & Lendl, 2002;Glories, 1978;Sarni-Manchado, Cheynier, & Moutounet, 1999). In a previous work (Monteleone, Condelli, Dinnella, & Bertuccioli, 2004) astringency induced by commercial polyphenolic extracts proved to be linearly related to the sampleÕs capability of developing turbidity by reacting with mucin in an in vitro assay.…”