Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme that is responsible for formation of important biological mediators called prostanoids, including prostaglandins, prostacyclin and thromboxane. Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain. Drugs, like Aspirin, that inhibit cyclooxygenase activity have been available to the public for about 100 years. Two cyclooxygenase isoforms have been identified and are referred to as COX-1 and COX-2. Under many circumstances the COX-1 enzyme is produced constitutively (i.e., gastric mucosa) whereas COX-2 is inducible (i.e., sites of inflammation). Non-steroidal anti-inflammatory drugs (NSAID), such as aspirin and ibuprofen, exert their effects through inhibition of COX. The main COX inhibitors are the non-steroidal anti-inflammatory drugs (NSAIDs).
Acetaminophen (paracetamol) is a selective cyclooxygenase-2 (COX-2) inhibitor with an IC50 of 25.8 μM; is a widely used antipyretic and analgesic drug.
Paradol is a pungent phenolic substance found in ginger and other Zingiberaceae plants. Paradol is an effective inhibitor of tumor promotion in mouse skin carcinogenesis, binds to cyclooxygenase (COX)-2 active site.
Diflunisal (MK-647) is a salicylate derivative with nonsteroidal anti-inflammatory and uricosuric properties, which is used alone as an analgesic and in rheumatoid arthritis patients. The mechanism of action of diflunisal is as a Cyclooxygenase (COX) Inhibitor.
Naproxen etemesil is a lipophilic, non-acidic, inactive prodrug of naproxen that is hydrolysed to pharmacologically active Naproxen once absorbed. Naproxen is a COX-1 and COX-2 inhibitor with IC50s of 2.2 and 1.3 μg/mL, respectively in cell assay.
Rofecoxib(MK 966) is a potent inhibitor of the COX-2-dependent production of PGE2 in human osteosarcoma cells (IC50= 26±10 nM) and Chinese hamster ovary cells expressing human COX-2 (IC50=18±7 nM).
Ginsenoside Rg3 is the main component of Red ginseng. Ginsenoside Rg3 inhibits Na+ and hKv1.4 channel with IC50s of 32.2±4.5 and 32.6±2.2 μM, respectively. Ginsenoside Rg3 also inhibits Aβ levels, NF-κB activity, and COX-2 expression.
NS-398 is a COX-2 inhibitor. The COX-1 activity is completely unaffected by 100 μM NS-398, whereas the COX-2 activity was concentration-dependently inhibited, the IC50 value being 3.8 μM.
Xanthohumol is one of the principal flavonoids isolated from hops, the inhibitor of diacylglycerol acetyltransferase (DGAT), COX-1 and COX-2, and shows anti-cancer and anti-angiogenic activities.
Ginsenoside C-K, a bacterial metabolite of G-Rb1, exhibits anti-inflammatory effects by reducing iNOS and COX-2. Ginsenoside C-K exhibits an inhibition against the activity of CYP2C9 and CYP2A6 in human liver microsomes with IC50s of 32.0±3.6 μM and 63.6±4.2 μM, respectively.
Flufenamic acid is a member of the NSAID drugs, is a COX inhibitor and prevents formation of prostaglandins, binds to and reduce the activity of prostaglandin F synthase and activate TRPC6.
(-)-Epicatechin inhibits cyclooxygenase-1 (COX-1) with an IC50 of 3.2 μM. (-)-Epicatechin inhibits the IL-1β-induced expression of iNOS by blocking the nuclear localization of the p65 subunit of NF-κB.
