Figure 3.

The effects of OQ1 and OQ21 on LPS-induced PGE₂ production and enzyme activity of COX-2. A. RAW264.7 cells were incubated with LPS (0.1 µg·mL⁻¹) and various concentrations of OQ1 or OQ21 for 8 h. The levels of accumulated PGE₂ were determined in the medium by PGE₂ EIA. B. RAW264.7 cells were stimulated with LPS for 8 h to induce COX-2 and washed with fresh media to remove LPS. Cells were further treated with OQ1 or OQ21 for 30 min followed by the addition of arachidonic acid (30 µmol·L⁻¹) as a substrate for COX-2. After 15 min, the levels of PGE₂ in media were determined using PGE₂ EIA. C. After purified COX-1/-2 enzymes were incubated with OQ1, OQ21 or indomethacin (IND) for 30 min, COX activities were measured by colorimetric assessment. Values are means ± SEM (n = 4–5). * represents a significant difference from LPS-treated control by one-way anova followed by Duncan's multiple range test (P < 0.05). OQ1, 6-(4-fluorophenyl)-amino-5,8-quinolinedione; OQ21, 6-(2,3,4-trifluorophenyl)-amino-5,8-quinolinedione; LPS, lipopolysaccharide; PGE₂, prostaglandin E₂; COX, cyclooxygenase.