A comparative study of the effects of quercetin and its glucuronide and sulfate metabolites on human neutrophil function in vitro.

Exposure of neutrophils to either lipopolysaccharide (LPS) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) is associated with changes in the expression of cell adhesion molecules and elevation of intracellular calcium ions. Although dietary flavonoids are reported to possess anti-inflammatory properties, little is known regarding the effect of their metabolites. We have investigated the effects of quercetin and its major metabolites on LPS and fMLP-stimulated human neutrophils using concentrations comparable to those reported in feeding studies on human volunteers.