A Series of COX-2 Inhibitors Endowed with NO-Releasing Properties: Synthesis, Biological Evaluation, and Docking Analysis (original) (raw)
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Proceedings of the National Academy of Sciences, 2000
All nonsteroidal antiinflammatory drugs (NSAIDs) inhibit the cyclooxygenase (COX) isozymes to different extents, which accounts for their anti-inflammatory and analgesic activities and their gastrointestinal side effects. We have exploited biochemical differences between the two COX enzymes to identify a strategy for converting carboxylate-containing NSAIDs into selective COX-2 inhibitors. Derivatization of the carboxylate moiety in moderately selective COX-1 inhibitors, such as 5,8,11,14-eicosatetraynoic acid (ETYA) and arylacetic and fenamic acid NSAIDs, exemplified by indomethacin and meclofenamic acid, respectively, generated potent and selective COX-2 inhibitors. In the indomethacin series, esters and primary and secondary amides are superior to tertiary amides as selective inhibitors. Only the amide derivatives of ETYA and meclofenamic acid inhibit COX-2; the esters are either inactive or nonselective. Inhibition kinetics reveal that indomethacin amides behave as slow, tight-binding inhibitors of COX-2 and that selectivity is a function of the time-dependent step. Site-directed mutagenesis of murine COX-2 indicates that the molecular basis for selectivity differs from the parent NSAIDs and from diarylheterocycles. Selectivity arises from novel interactions at the opening and at the apex of the substrate-binding site. Lead compounds in the present study are potent inhibitors of COX-2 activity in cultured inflammatory cells. Furthermore, indomethacin amides are orally active, nonulcerogenic, anti-inflammatory agents in an in vivo model of acute inflammation. Expansion of this approach can be envisioned for the modification of all carboxylic acid-containing NSAIDs into selective COX-2 inhibitors. This paper was submitted directly (Track II) to the PNAS office.
A review on COX and their inhibitors: Present and future
2014
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. These prostaglandins are also known as autocoid mediators that affect virtually all known physiological and pathological processes via their reversible interaction with G-protein coupled membrane receptors. Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain. The inflammatory molecule PGE2 lowers pain thresholds and the primary goal of oral inhibitors of PGE2 is to reduce pain. This review article provides an overview and an update on the progress achieved in the area of COX inhibitors and their role in health and disease conditions. It also discusses some unresolved issues related to the use of selective COX-2 inhibitors as a safe and promising therapeutic option not only for the treatment of inflamm...
Evaluation of COX-1/COX-2 selectivity and potency of a new class of COX-2 inhibitors
European Journal of Pharmacology, 2008
A new class of selective cyclooxygenase-2 (COX-2) inhibitors has been identified by high throughput screening. Structurally distinct from previously described selective COX-2 inhibitors, these benzopyrans contain a carboxylic acid function and CF 3 functionality. The compound SC-75416 is a representative of this class. A range if in vitro and in vivo tests were employed to characterize its potency and selectivity. Using human recombinant enzymes, this compound displays a concentration that provides 50% inhibition (IC 50 ) of 0.25 μM for COX-2 and 49.6 μM for COX-1. A mutation of the side pocket residues in COX-2 to COX-1 had little effect on potency suggesting that these inhibitors bind in a unique manner in COX-2 distinct from COX-2 inhibiting diaryl heterocycles. Using rheumatoid arthritic synovial cells stimulated with interleukin-1β (IL-1β) and washed platelets the compound displayed IC 50 of 3 nM and 400 nM respectively. Potency and selectivity was maintained but predictably right shifted in whole blood with IC 50 of 1.4 μM for lipopolysaccharide (LPS) stimulated induction of COX-2 and N 200 μM for inhibition of platelet thromboxane production. SC-75416 is 89% bioavailable and its in vivo half life is sufficient for once a day dosing. In the rat air pouch model of inflammation, the compound inhibited PGE 2 production with an effective dose that provides 50% inhibition (ED 50 ) of 0.4 mg/kg, while sparing gastric prostaglandin E2 (PGE 2 ) production with an ED 50 of 26.5 mg/kg. In a model of acute inflammation and pain caused by carrageenan injection into the rat paw, the compound reduced edema and hyperalgesia with ED 50 s of 2.7 and 4 mg/kg respectively. In a chronic model of arthritis the compound demonstrated an ED 50 of 0.081 mg/kg and an ED 80 of 0.38 mg/kg. In a model of neuropathic pain, SC-75416 had good efficacy. This compound's unique chemical structure and effect on COX enzyme binding and activity as well as its potency and selectivity may prove useful in treating pain and inflammation.
Purpose. NSAIDs constitute an important class of drugs with therapeutic applications that have spanned several centuries. Treatment of inflammatory conditions such as rheumatoid arthritis (RA) and osteoarthritis (OA) starting from the classic drug aspirin to the recent rise and fall of selective COX-2 inhibitors has provided an enthralling evolution. Efforts to discover an ultimate magic bullet to treat inflammation continues to be an important drug design challenge. This review traces the origins of NSAIDs, their mechanism of action at the molecular level such as cyclooxygenase (COX) inhibition, development of selective COX-2 inhibitors, their adverse cardiovascular effects, and some recent developments targeted to the design of effective anti-inflammatory agents with reduced side effects. Methods. Literature data is presented describing important discoveries pertaining to the sequential development of classical NSAIDs and then selective COX-2 inhibitors, their mechanism of action, the structural basis for COX inhibition, and recent discoveries. Results. A brief history of the development of NSAIDs and the market withdrawal of selective COX-2 inhibitors is explained, followed by the description of prostaglandin biosynthesis, COX isoforms, structure and function. The structural basis for COX-1 and COX-2 inhibition is described along with methods used to evaluate COX-1/COX-2 inhibition. This is followed by a section that encompasses the major chemical classes of selective COX-2 inhibitors. The final section describes briefly some of the recent advances toward developing effective anti-inflammatory agents such as nitric oxide donor NO-NSAIDs, dual COX/LOX inhibitors and anti-TNF therapy. Conclusions. A great deal of progress has been made toward developing novel anti-inflammatory agents. In spite of the tremendous advances in the last decade, the design and development of a safe, effective and economical therapy for treating inflammatory conditions still presents a major challenge.
Anti-inflammatory and side effects of cyclooxygenase inhibitors
Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly used drugs in inflammatory diseases, since they are effective in management of pain, fever, redness, edema arising as a consequence of inflammatory mediator release. Studies have shown that both therapeutic and side effects of NSAIDs are dependent on cyclooxygenase (COX) inhibition. COX isoforms have been named constitutive (COX-1) and inducible (COX-2). COX-1 catalyzes formation of cytoprotective prostaglandins in thrombocytes, vascular endothelium, stomach mucosa, kidneys, pancreas, Langerhans islets, seminal vesicles, and brain. Induction of COX-2 by various growth factors, proinflammatory agents, endotoxins, mitogens, and tumor agents indicates that this isoform may have a role in induction of pathological processes, such as inflammation. It is well known that therapy with COX inhibitors is associated with a number of side effects including gastrointestinal erosions, and renal and hepatic insufficiency. Such critical adverse reactions are mostly dependent on COX-1 inhibition. As a result of research focused on reduction of the adverse effects of NSAIDs, selective COX-2 inhibitors, such as celecoxib and rofecoxib have been developed. However, many data demonstrate that mechanisms of action of these drugs are multidirectional and complex. These drugs or their derivatives, which belong to the same group, have distinct pharmacological effects, side effects and potencies which implies that there may be more than two, five or even tens of COX isoforms.
Progress in COX2 Inhibitors: A Journey So Far
Current Medicinal Chemistry, 2010
The non-steroidal anti-inflammatory drugs (NSAIDs) are diverse group of compounds used for the treatment of inflammation, since the introduction of acetylsalicylic acid in 1899. Traditional (first generation) NSAIDs exert antiinflammatory, analgesic, and antipyretic effects through the blockade of prostaglandin synthesis via non-selective inhibition of cyclooxygenase (COX-1 and COX-2) isozymes. Their use is associated with side effects such as gastrointestinal and renal toxicity. A number of selective (second generation) COX-2 inhibitors (rofecoxib, celecoxib, valdecoxib etc.) were developed as safer NSAIDs with improved gastric safety profile. Observation of increased cardiovascular risks in APPROVe (Adenomatous Polyp Prevention on Vioxx) study sent tremors and led to voluntary withdrawn of Vioxx (rofecoxib) by Merck from the market in September 2004 followed by Bextra (valdecoxib) in 2005 raising a question on the safety of selective COX-2 inhibitors. This leads to the belief that these effects are mechanism based and may be class effect. However, some studies suggested association of traditional NSAIDs with similar effects requiring a relook into the whole class of NSAIDs rather than simply victimizing the selective COX-2 inhibitors. Recognition of new avenues for selective COX-2 inhibitors such as cancer, Alzheimer's disease, Parkinson's disease, schizophrenia, major depression, ischemic brain injury and diabetic peripheral nephropathy has kindled the interest in these compounds. This review highlights the various structural classes of selective COX-2 inhibitors developed during past seven years (2003)(2004)(2005)(2006)(2007)(2008)(2009) with special emphasis on diaryl-hetero/carbo-cyclic class of compounds. Molecular modeling aspects are also briefly discussed.