Cyclooxygenase enzymatic activity in microglial cells is inhibited by resveratrol treatment. For the COX-1 activity assay (A), cells were left untreated and different concentrations of resveratrol were added for 15 min. After this incubation time, 15 μM of arachidonic acid was added and PGE2 measured after 15 min. For total COX activity assay (COX-1 + COX-2), cells were either left untreated or were stimulated with LPS (10 ng/ml) for 24 h. After removal of medium, cells were treated with different concentrations of resveratrol for 30 min in absence or presence of 15 μM of arachidonic acid. PGE2 in the supernatants was measured by an enzyme immunoassay as described in Materials and Methods. Data are expressed as mean ± S.E.M. Statistical analysis was performed using one-way ANOVA followed by the Student-Newman-Keuls post-hoc test. *p < 0.05 and **p < 0.01 with respect to untreated control (without resveratrol).