SO treatment inhibits PGE2 production and COX-2 expression among LPS-treated RAW264.7 cells. (A) The chemical structure of SO. (B, D) Inhibitory activity of SO or indomethacin on PGE2 production was assessed among LPS-treated RAW264.7 cells (1 × 106 cells/ml) through the detection of PGE2 release into the culture medium with an EIA kit. (C) The viability of SO-treated RAW264.7 cells (1 × 106 cells/ml) was determined through MTT assay. (E) The mRNA level of COX-2 among SO/LPS-treated RAW264.7 cells (1 × 106 cells/ml) was determined by semiquantitative (Left panel) and real-time (Right panel) PCR. Similar inhibitory patterns were observed in two repeat experiments. ##P < 0.01 compared to the normal group and *P < 0.05 or **P < 0.01 compared to control groups. Normal group: no-treatment group. Control group: LPS alone group.