The second isoform is found in sheep placental cotyledones and its microsomal preparations have become a target for the discovery of selective PGHS-2 inhibitors (Johnson et al.
The assay was performed in a microtiter scale with purified PGHS-2 from sheep placental cotyledones (Cayman Chemical) (Johnson et al.
The determination of PGHS-1 inhibition was performed according to the PGHS-2 assay with 0.
The presented assays are performed with purified PGHS-2 from sheep placental cotyledones (Johnson et al.
2]EDTA protects PGHS-2 from inactivation by metalloproteases, but does not interfere with the enzyme activity.
The PGHS-1 and PGHS-2 assays are directly comparable, because both enzymes are purified and from the same species.
Known specific PGHS-2 inhibitors showed better inhibitory effects for PGHS-2 than PGHS-1 e.
They all exhibited inhibitory activity towards PGHS-1 and PGHS-2 in a similar range (Table 2).
At a concentration of 50 [micro]g/ml the lipophilic extracts, n-hexane (50 [+ or -] 6%) and DCM (70 [+ or -] 8%) exhibited good inhibitory activity on PGHS-1 and PGHS-2, however, without a statistical significant selective inhibitory effect on one of the two PGHS isoforms.
Only when the raw material was extracted directly with DCM, the extract showed better PGHS-2 than PGHS-1 inhibitory activity (I[C.
The polyunsaturated fatty acids, linoleic acid and [alpha]-linolenic acid showed better inhibitory activity on PGHS-2 than on PGHS-1.
According to these results, linoleic acid is mainly responsible for the in vitro PGHS-2 inhibitory activity of this extract.