Fig. 2.

Effects of QG on LPS-induced extracellular release of NO (A) and PGE₂. (B) in RAW264.7 macrophage cells. RAW264.7 cells were pretreated with indicated concentrations of QG for 1 hr before incubation with LPS (200 ng/ml) for 24 hrs. The level of nitrite and PGE₂ were measured using Griess reagent and ELISA assay, respectively. QG significantly suppressed LPS-induced extracellular secretion of NO and PGE₂. (C) Effect of QG on the viability of RAW264.7 cells. No significant cell death was observed with QG concentrations used in the present study. The data were obtained from three independent experiments and expressed as mean ± SD (n=3). ^*p<0.05 and ^**p<0.01 indicate statistically significant differences from treatment with LPS alone. QC and Q stand for quercetin-3-O-β-D-glucuronide and quercetin, respectively. Quercetin was used as a reference. Examination of quercetin at 100 μM concentration was not done due to the decreased cell viability.