Effect Of Quercetin And Epigallocatechin-3-Gallate On Anti-inflammatory Activity In Vitro And In Vivo

Prolonged, exhaustive exercise is associated with significant acute and chronic effects on the immune system of human athletes. Quercetin, a flavonoid ubiquituously found in the human diet, has been highly investigated for its potential use as a performance enhancing nutraceutical. The purpose of this thesis study was to assess quercetin’s anti-inflammatory potential by first testing two of the biologically relevant quercetin conjugates in vitro using lipopolysaccharide (LPS) stimulated human peripheral blood mononuclear cells (PBMCs). This same in vitro model was used to optimize the ratio at which quercetin aglycone and epigallocatechin-3-gallate (EGCG) combined might exert the most potent anti-inflammatory effect. The optimized flavonoid ratio was then utilized in subsequent in vivo testing using an exercising mouse model. Findings from this study indicate that conjugation with either glucuronide or sulfate eliminates quercetin aglycone’s anti-inflammatory effect in vitro. In addition, EGCG failed to synergistically boost quercetin aglycone’s anti-inflammatory effect in the same in vitro model. Nevertheless, a 5:1 ratio of quercetin to EGCG was chosen for subsequent in vivo testing. However, quercetin and cytokine analysis from the plasma of exercised mice failed to demonstrate a requirement for EGCG in either substantiating quercetin’s effect on post-exercise inflammation or improving quercetin’s bioavailability in vivo.