Cyclooxygenase inhibitory activity of ginsenosides from heat-processed ginseng

Ginsenosides, from heat-processed ginseng, and sapogenins were evaluated for their inhibitory effects on the enzyme catalytic activities of cyclooxygenases-1 and -2 (COX-1 and -2). The ginsenosides, 20(S)-Rg3, Rg5, and Rk1, inhibited COX-2 activity, but did not affect the enzyme activity of COX-1. Protopanaxatriol (PPT) moderately inhibited both COX-1 and -2. The ginsenosides, 20(R)-Rg3, Re, and protopanaxadiol (PPD) showed a minimal effect on COX-1 and -2 activities. Taken together, ginsenosides Rg3 (20S-form), Rg5 and Rk1 showed selective inhibitory activity on COX-2 by behaving as an inhibitor of the enzyme–substrate reaction.