Fig 4. Mole fractions of polyphenols bound to human saliva proteins as assessed by single comparative qHNMR measurements.

Aliquots (10 μL, 2.5 mmol/L) of the polyphenolic compounds EC, EGC, ECG, EGCG, methyl gallate, rutin, and saccharin were each mixed with pooled and centrifuged, non-stimulated saliva (990 μL). As crude saliva was previously blended with phosphate buffer in a 9:1 ratio (v/v), the total saliva content was 89.1%. Samples lacking saliva served as references. Error bars denote the standard deviation obtained from two independent measurements of biological replicates, integrating all distinct, non-overlaid proton signals of each ligand (see methods for a list of consulted proton resonance signals and S2 Table for the data points behind means). Saccharin showed no binding (n.b.) with human saliva.