4.10. COX Inhibitory Assay

The ability of the (AJ) EO to prevent the conversion of arachidonic acid to PGH2 by bovine COX-1 and human recombinant COX-2 was assessed using a COX inhibitor screening assay kit (Item No: 560131, Cayman Chemical, Ann Arbor, MI, USA) according to manufacturer’s guidelines. The 50% inhibitory concentration (IC₅₀) of COX-1/COX-2 activity of the tested samples was determined, with the assay run, in duplicate, with two concentrations (350 and 50 µg/mL). A standard curve of eight concentrations of prostaglandin, a non-specific binding sample, and a maximum binding sample was used, as instructed in the kit manual, to determine the inhibition of the sample plant, applying the generated multiple regression best-fit line. The percentage inhibition of the two concentrations was used to calculate the IC₅₀ [69,70].