Background: Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most
widely used therapeutics; they are competitive inhibitors of cyclooxygenase (COX), the enzyme
which mediates the conversion of arachidonic acid to inflammatory prostaglandins.
Objective: In this study, new benzodioxol derivatives with different core cycles and functional
groups (i.e., aryl acetate, aryl acetic acid and diazepine) were designed, synthesized, identified and
evaluated for their analgesic and anti-inflammatory activity, as a preliminary screening study to
identify the most potent and more selective groups.
Methods: The synthesized compounds were identified using FTIR, HRMS, 1H-NMR and 13C-NMR,
and evaluated for their inhibitory activity against ovine COX-1 and COX-2 using an in-vitro
cyclooxygenase (COX) inhibition assay kit.
Results: Six compounds were synthesized as a preliminary screening study to identify which was the
most potent and more selective group towards COX-2 versus COX-1, compared to ketoprofen as nonselective NSAIDs. The compounds have three different groups: aryl acetate, aryl acetic acid and
diazepine. The results showed that the most potent compound against the COX-1 enzyme
was 4b (which has diazepine and 2-chlorophenyl) with IC50 = 0.363 µM, and the selectivity ratio of 4b
was found to be better than ketoprofen. In contrast, compound 4a (which has diazepine and 3-
chlorophenyl) was the most selective with a COX-1/COX-2 ratio value of 0.85 in comparison with a
ketoprofen ratio value of 0.20.
Conclusion: In general, the synthesized library has moderate activity against both enzymes (i.e.,
COX-1 and COX-2). Moreover, all six compounds have better COX-2 inhibition selectivity compared
to the commercial drug ketoprofen.