Effects of quercetin and epigallocatechin gallate on the inflammatory response of stimulated human peripheral blood mononuclear cells (PBMC)

Abstract

This study evaluated the ability of epigallocatechin gallate enriched green tea extract (EGCG) to augment quercetin's (Q) inhibition of lipopolysaccharide (LPS)‐induced pro‐inflammatory cytokine secretion in vitro. PBMCs isolated from healthy male adults (n=5) were incubated for one hour with either 25 μM of Q or 5 μM of EGCG alone or in combination, followed by 23 hours of LPS (0.1 μg/ml) stimulation. Inflammatory effects were assessed by quantifying concentrations of three cytokines (TNF‐α, IL‐6, and IL‐1β) in cell supernatant using a chemoluminescence based solid‐phase sandwich immunoassay (Meso Scale Discovery, Gaithersburg, MD, USA). Q alone or in combination with EGCG significantly decreased TNF‐α (P=0.012 and 0.006, respectively), IL‐6 (P<0.001 and P=0.001, respectively), and Il‐1β (P=0.013 and 0.006, respectively), however Q combined with EGCG did not significantly differ from Q alone. In conclusion, EGCG did not effectively augment the anti‐inflammatory effects of Q on LPS‐stimulated cytokine production by PBMC in vitro.