After plaunotol stimulation, COX-1 and COX-2 expression were detected with their specific antibodies. When plaunotol was added at 50, 100, and 200 μM, COX-2 expression was stronger than that of controls. On the other hand, there was no significant difference in COX-1 expression between groups with or without the addition of plaunotol (Fig. 3A). The reporter assay indicated that the luciferase activity in the long-type construct but not in short-type was significantly increased after plaunotol treatment (Fig. 3B), which was consistent with the COX-2 expression induced by plaunotol. Moreover plaunotol (50, 100, or 200 μM) significantly increased PGE2 levels in the culture medium compared to the control group (Fig. 4).