8298
When two 4-trifluoromethyl salicylate derivatives [ 2-acetoxy-4-trifluoromethyl-benzoic acid ( triflusal ) and its deacetylated metabolite 2-hydroxy-4-trifluoromethylbenzoic acid ( HTB )] were compared with aspirin and sodium salicylate as cyclooxygenase-2 (COX-2) inhibitors, we observed that in bacterial lipopolysaccharide-activated human blood , triflusal , aspirin , and HTB , but not sodium salicylate , inhibited COX-2-mediated prostaglandin E2 ( PGE2 ) production (IC50 = 0.16, 0.18, 0.39, and >10 mM, respectively).
 ( protein: cyclooxygenase-2, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: cyclooxygenase-2, None) 