Figure 4: Four different flavonoids inhibited nitric oxide production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. (a) Cells were treated with or without 1 μg/mL LPS and 0–12.5 μg/mL quercetin, kaempferol, galangin, or curcumin as indicated for 24 h and cell viability was evaluated on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results are expressed as percentages of no-treatment control (NC) values (100%). (b) Nitric oxide production rates in the media were evaluated on Griess reagent assay. Results are shown as percentages of the LPS only values (100%). #P < 0.05 compared to NC; *P < 0.05 compared LPS only.