Table 2. Effects of Triterpene Acids from Gum Resins of Boswellia spp. on COX-1 and COX-2 Activity in a Cell-Free Assay (mean ± SEM, n = 3, 4).

compound	COX-1 residual activity at 10 μM	COX-2 residual activity at 10 μM
5	81.9 ± 8.3	n.d.c
6	63.2 ± 4.1	81.8 ± 3.1
7	82.3 ± 1.2	83.4 ± 8.6
8	81.1 ± 6.5	70.1 ± 7.0
9	69.6 ± 3.7	83.4 ± 3.7
13	64.8 ± 9.5	66.3 ± 7.6
17	90.7 ± 7.7	75.8 ± 6.4
indomethacina	41.3 ± 5.2	n.d.
celecoxibb	n.d.	22.4 ± 3.8

^aIndomethacin, 10 μM, reference compound for COX-1.

^bCelecoxib, 5 μM, reference compound for COX-2.

^cn.d. = not determined.