Carnosol and carnosic acid inhibit mPGES-1 activity. A, structures of carnosol (left) and carnosic acid (right). B, concentration-response curves for carnosol and carnosic acid. The effect of carnosol and carnosic acid on mPGES-1 activity was determined under the same conditions as described in the legend to Fig. 1. C, effect of vehicle (DMSO, w/o), ursolic acid, oleanolic acid, rosmarinic acid, and the mPGES-1 control inhibitor MK-886 (10 μM, each) on mPGES-1 activity. Values of 100% correspond to 306 ± 63 ng of PGE2. Data are given as mean + S.E. (n = 3-5). **, p < 0.01 or ***, p < 0.001 versus vehicle (DMSO) control, ANOVA + Tukey HSD post hoc tests.