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The present work describes the design and synthesis of novel series of ten pyrazolo[3,4- d ]pyrazolo derivatives. Four compounds 3a , 3d , 4d and 4f were notable for their anti-inflammatory activity that was comparable to that of the clinically available cyclooxygenase-2 inhibitor celecoxib. They are even more potent than non-sterodial anti-inflammatory drug cyclooxygenase inhibitor diclofenac sodium. Our best hit 4d appears to adopt similar binding modes to the standard COX-2 inhibitor, celecoxib, proposing room for possible selectivity. The in silico findings come in line with the in vitro and in vivo assay results and also suggest that these compounds have the potetntial to be COX-2 selective inhibitors since they have typical binding modes of the benchmark drug celecoxib. • Design and synthesis of novel series of pyrazolo[3,4- d ]pyrazolo derivatives. • The best hit, 4d with COX-1 IC 50 of 28 µM and COX-2 IC 50 of 23 µM. • 4d adopt similar binding modes to the standard COX-2 inhibitor, celecoxib. • 3a , 3d , 4d and 4f exhibited anti-inflammatory activity that was comparable to celecoxib. In this study, the acid chlorides of pyrazolo[3,4- d ]pyrimidine compounds were prepared and reacted with a number of nucleophiles. The novel compounds were experimentally tested via enzyme assay and they showed cyclooxygenase-2 inhibition activity in the middle micro molar range (4b had a COX-1 IC 50 of 26 µM and a COX-2 IC 50 of 34 µM, 3b had a COX-1 IC 50 of 19 µM and a COX-2 IC 50 of 31 µM, 3a had a COX-2 IC 50 of 42 µM). These compounds were analyzed via docking and were predicted to interact with some of the COX-2 key residues. Our best hit, 4d (COX-1 IC 50 of 28 µM, COX-2 IC 50 of 23 µM), appears to adopt similar binding modes to the standard COX-2 inhibitor, celecoxib, proposing room for possible selectivity. Additionally, the resultant novel compounds were tested in several in vivo assays. Four compounds 3a (COX-2 IC 50 of 42 µM), 3d , 4d and 4f were notable for their anti-inflammatory activity that was comparable to that of the clinically available COX-2 inhibitor celecoxib. Interestingly, they showed greater potency than the famous non-steroidal anti-inflammatory drug, Diclofenac sodium. In summary, these novel pyrazolo[3,4- d ]pyrimidine analogues showed interesting anti-inflammatory activity and could act as a starting point for future drugs. [ABSTRACT FROM AUTHOR]

Two new series of pyrazolo[3,4- d ]pyrimidine bearing thiazolidinone moiety were designed and synthesized. The newly synthesized compounds were evaluated for their in vitro (COX-1 and COX-2) inhibitory assay . Compounds that showed promising COX-2 selectivity were further subjected to in vivo anti-inflammatory screening applying formalin induced paw edema (acute model) and cotton-pellet induced granuloma (chronic model) assays using celecoxib and diclofenac sodium as reference drugs . The histopathological and ulcerogenic potential were also determined. In vivo anti-inflammatory data showed that compounds 2 , 6 , 7d displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, compounds 2 , 3d , 3e , 7b and 7d displayed anti-inflammatory activity greater than or nearly equivalent to diclofenac sodium in the cotton pellet-induced granuloma assay. Moreover, most of the tested compounds revealed good gastrointestinal safety profile. Collectively, compounds 2 and 7d were considered as promising candidates in managing both acute and chronic inflammation with safe gastrointestinal margin. [ABSTRACT FROM AUTHOR]

Background Current evidence regarding the effects of selective cyclooxygenase inhibitors on gastrointestinal anastomoses is controversial. An experimental randomized control study was conducted in our institution to histopathologically evaluate the consequences of parecoxib, on intestinal and abdominal wound healing. Methods Twenty-four adult Wistar rats underwent laparotomy, ascending colon transection, and hand-sewn anastomosis. They were randomized to receive either parecoxib (0.5 mg/kg twice daily) or 0.9% normal saline by intraperitoneal injection postoperatively. Animals were euthanatized either on the third or the seventh postoperative day. Semiquantitative methods were used to evaluate both intestinal and abdominal wounds for inflammatory cell composition, angiogenesis, fibroblasts, granular tissue, collagen deposition, epithelization, and presence of necrosis, exudate, and abscess formation. Results are presented as (parecoxib: median [IQR] versus control: median [IQR], P -value). Results No macroscopic anastomotic leakage or wound dehiscence was observed. Intestinal anastomoses in the parecoxib group, showed significantly decreased epithelization (2 [1] versus 3 [1], [ P = 0.004]) and collagen deposition (2 [0] versus 3 [1], [ P = 0.041]). No difference was observed in angiogenesis (3 [1] versus 2.5 [1], [ P = 0.158]). Abdominal wall specimens appeared to demonstrate decreased epithelization (2 [2] versus 4 [0.5], [ P = 0.0004]) in the treatment group. No difference between the two groups was identified regarding collagen deposition (2.5 [1] versus 2 [0.5], [ P = 0.280]) and angiogenesis (2.5 [1] versus 2 [1], [ P = 0.633]). Necrosis was significantly more present in the parecoxib group in both specimen types, (3.5 [1] versus 2.5 [1], [ P = 0.017]) and (3 [1] versus 1 [0.5], [ P < 0.0001]). Conclusions The present study shows that despite the absence of clinical adverse effects, parecoxib can impair anastomotic and abdominal wound healing on a histopathological level. [ABSTRACT FROM AUTHOR]

A series of new 1,3,4-oxadiazole/oxime hybrids were synthesized and designed as potent COX inhibitors. The prepared compounds were evaluated for their anti-inflammatory, antioxidant and ulcerogenic activities. The results indicated that the prepared compounds exhibited remarkable anti-inflammatory activity with (69.60–109.60% of indomethacin activity) after 4 h. In vitro COX inhibitory assay showed that compounds 6d and 7h are potent COX inhibitors with IC 50 of (1.10–0.94) and (2.30–5.00) µM on both COX-1 and COX-2 respectively. Compound 7h was found to inhibit both COXs non-competitively with K i values of 73 µM and 89 µM. Most of the tested compounds showed ulcer-free stomachs compared to indomethacin. [ABSTRACT FROM AUTHOR]

Introduction Individuals of African descent (AFD) are more susceptible to non-freezing cold injury (NFCI) compared with Caucasian individuals (CAU). Vasodilatation to acetylcholine (ACh) is lower in AFD compared with CAU in the non-glabrous foot and finger skin sites; the reason for this is unknown. Prostanoids are responsible, in part, for the vasodilator response to ACh, however it is not known whether the contribution differs between ethnicities. Methods 12 CAU and 12 AFD males received iontophoresis of ACh (1 w/v%) on non-glabrous foot and finger skin sites following placebo and then aspirin (600 mg, single blinded). Aspirin was utilised to inhibit prostanoid production by inhibiting the cyclooxygenase (COX) enzyme. Laser Doppler flowmetry was utilised to measure changes in skin blood flow. Results Not all participants could receive iontophoresis charge due to high skin resistance; these participants were therefore excluded from the analyses. Foot : ACh elicited greater maximal vasodilatation in CAU than AFD following placebo ( P = 0.003) and COX inhibition (COXib) ( P < 0.001). COXib did not affect blood flow responses in AFD, but caused a reduction in the area under the curve for CAU ( P = 0.031). Finger : ACh elicited a greater maximal vasodilatation in CAU than AFD following placebo ( P = 0.013) and COXib ( P = 0.001). COXib tended to reduce the area under the curve in AFD ( P = 0.053), but did not affect CAU. Conclusions CAU have a greater endothelial reactivity than AFD in both foot and finger skin sites irrespective of COXib. It is concluded that the lower ACh-induced vasodilatation in AFD is not due to a compromised COX pathway. [ABSTRACT FROM AUTHOR]

A new series of 1,3,5-triaryl-4,5-dihydro-1 H -pyrazole 10a – l was designed and synthesized via cyclization of chalcones 8a – f with 4-amino/methanesulfonylphenylhydrazine hydrochloride 9a – b . All the synthesized compounds were evaluated for their cyclooxygenase (COX) inhibition, anti-inflammatory activity, ulcerogenic liability and analgesic activity. All compounds were more COX-2 inhibitors than COX-1. While most compounds showed good anti-inflammatory activity, the trimethoxy derivatives ( 10a , 10b, 10g and 10h ) were the most potent derivatives (ED 50 = 55.78, 53.99, 67.65 and 69.20 μmol/kg respectively) in comparison with celecoxib (ED 50 = 82.15 μmol/kg). Compounds 10a , 10b, 10g and 10h (ulcer index = 2.68, 1.20, 2.63 and 2.66 respectively) showed less ulceration effect than celecoxib (ulcer index = 2.90). Also, Compounds 10a , 10b, 10g and 10h showed analgesic activity higher than celecoxib and comparable to that of ibuprofen. In addition, molecular docking studies were performed for compounds 10a , 10b, 10g and 10h and the results were in agreement with that obtained from the in vitro COX inhibition assays. [ABSTRACT FROM AUTHOR]

Although the cure of amyloid related neurodegenerative diseases, non-neuropathic amyloidogenic diseases and non-neuropathic systemic amyloidosis are appealing energetic research attempts, beneficial medication is still to be discovered. There is a need to explore intensely stable therapeutic compounds, potent enough to restrict, disrupt or wipe out such toxic aggregates. We had performed a comprehensive biophysical, computational and cell based assay, that shows Nordihydroguaiaretic acid (NA) not only significantly inhibits heat induced hen egg white lysozyme (HEWL) fibrillation but also disaggregates preformed HEWL fibrils and reduces the cytoxicity of amyloid fibrils as well as disaggregated fibrillar species. The inhibitory potency of NA was determined by an IC 50 of 26.3 μM. NA was also found to effectively inhibit human lysozyme (HL) fibrillation. NA interferes in the amyloid fibrillogenesis process by interacting hydrophobically with the amino acid residues found in highly prone amyloid fibril forming region of HEWL as explicated by molecular docking results. The results recommend NA as a probable neuroprotective and promising inhibitor for the therapeutic advancement prospective against amyloid related diseases. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine whether Hymenolepis diminuta may affect the expression and activity of cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2), resulting in the altered levels of their main products – prostaglandins (PGE 2 ) and thromboxane B 2 (TXB 2 ). The study used the same experimental model as in our previous studies in which we had observed changes in the transepithelial ion transport, tight junctions and in the indicators of oxidative stress, in both small and large intestines of rats infected with H. diminuta . In this paper, we investigated not only the site of immediate presence of the tapeworm (jejunum), but also a distant site (colon). Inflammation related to H. diminuta infection is associated with the increased expression and activation of cyclooxygenase (COX), enzyme responsible for the synthesis of PGE 2 and TXB 2 , local hormones contributing to the enhanced inflammatory reaction in the jejunum and colon in the infected rats. The increased COX expression and activity is probably caused by the increased levels of free radicals and the weakening of the host's antioxidant defense induced by the presence of the parasite. Our immunohistochemical analysis showed that H. diminuta infection affected not only the intensity of the immunodetection of COX but also the enzyme protein localization within intestinal epithelial cells – from the entire cytoplasm to apical/basal regions of cells, or even to the nucleus. [ABSTRACT FROM AUTHOR]

For many years it has been recognized that inhibition of cyclooxygenase enzymes is effective in reducing the incidence of many types of cancer, but the adverse effects of these drug, particularly in the gastrointestinal and cardiovascular systems, limits their utility. Recently developed hydrogen sulfide-releasing anti-inflammatory drugs may be a promising option for cancer chemoprevention. In this paper we review evidence suggesting that these novel compounds are effective in a range of animal models of various types of cancer, while exhibiting greatly reduced toxicity relative to currently marketed non-steroidal anti-inflammatory drugs. Some of the possible mechanisms of action of hydrogen sulfide-releasing anti-inflammatory drugs are also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Summative view of tail-approach based selective as well as potent hCA IX and XII inhibitors reported in the last decade. • Listing of the most promising molecules in terms of selectivity and potency from the available 181 research papers. • One stop solution to tailor the tail-approach based rational design of novel libraries of carbonic anhydrase inhibitors. Human carbonic anhydrase (hCA) isoforms hCA IX and hCA XII are well established anticancer drug targets and their selective inhibition is highly desired for the proper treatment of cancer. Lack of isoform-selectivity in current clinically used CA inhibitors (CAIs) is a major concern as it leads to undesired side effects, associated with off-target inhibition. Thus, there is need to explore alternative approaches for the design of isoform-selective inhibitors and the leading promising approach for the design of isoform-selective CAIs is "the tail-approach". Virtually, most drug design studies in the last decade were done by considering the tail-approach reported in 1999. The past decade of 2010–2020 witnessed progressive maturation of this approach as a large number of CAIs have been designed and synthesised based on it, many of which turned out to be effective as well as selective hCA IX and hCA XII inhibitors. This review covers the past decade (2010–2020) research, considering selective as well as potent inhibitors of tumor associated isoforms, hCA IX and hCA XII, which include newer generation inhibitors containing sulfonamides or their bioisosteres, non-classical inhibitors (including carboxylic acid/ester, coumarin and sulfocoumarin classes) and various other novel classes of inhibitors belonging to newly identified chemotypes/scaffolds. [ABSTRACT FROM AUTHOR]

Overproduction of arachidonic acid (AA) mediated by secretory phospholipase A 2 group IIA (sPLA 2 IIA) is a hallmark of many inflammatory disorders. AA is subsequently converted into pro-inflammatory eicosanoids through 5-lipoxygenase (5-LOX) and cyclooxygenase-1/2 (COX-1/2) activities. Hence, inhibition of sPLA 2 IIA, 5-LOX and COX-1/2 activities is critical in regulating inflammation. We have previously reported unconjugated bilirubin (UCB), an endogenous antioxidant, as sPLA 2 IIA inhibitor. However, lipophilic UCB gets conjugated in liver with glucuronic acid into hydrophilic conjugated bilirubin (CB). Since hydrophobicity is pre-requisite for sPLA 2 IIA inhibition, conjugation reduces the efficacy of UCB. In this regard, UCB was chemically modified and derivatives were evaluated for sPLA 2 IIA, 5-LOX and COX-1/2 inhibition. Among the derivatives, BD1 (dimethyl ester of bilirubin) exhibited ∼ 3 fold greater inhibitory potency towards sPLA 2 IIA compared to UCB. Both UCB and BD1 inhibited human 5-LOX and COX-2 activities; however only BD1 inhibited AA induced platelet aggregation. Molecular docking studies demonstrated BD1 as better inhibitor of aforesaid enzymes than UCB and other endogenous antioxidants. These data suggest that BD1 exhibits strong anti-inflammatory activity through inhibition of AA cascade enzymes which is of great therapeutic importance. [ABSTRACT FROM AUTHOR]

Irisin, a newly discovered myokine, has been shown to produce modest weight loss and improve glucose intolerance in mice. The purpose of this study was to investigate the effects of irisin on vascular activity and the mechanisms involved. Experiments were performed on mouse mesenteric arteries. We demonstrated that irisin induced relaxation in mesenteric arteries with or without endothelium in a concentration-dependent manner. It was further demonstrated that the irisin-induced vasorelaxation effects on endothelium-intact mesenteric arteries were reduced by pretreatment with Nω-nitro- l -arginine methyl ester ( l -NAME) or 1H-[1, 2, 4] oxadizolo [4, 3-a] quinoxalin-1-one (ODQ). However, pretreatment with indomethacin (INDO), a nonselective cyclooxygenase inhibitor did not modulate irisin-induced relaxation. In addition, the contraction due to extracellular Ca 2+ influx and intracellular Ca 2+ release was also inhibited by irisin. In summary, these results suggested that the endothelium-dependent relaxation of irisin is mediated by the nitric oxide (NO)-guanosine 3′, 5′-cyclic phosphate (cGMP)-dependent pathway but not the prostaglandin I 2 (PGI 2 )-cyclic adenosine monophosphate (cAMP)-dependent mechanism. Endothelium-independent relaxation may be depend on inhibiting Ca 2+ influx through blocking VDCCs and intracellular Ca 2+ release through both IP3R and RyR channels. [ABSTRACT FROM AUTHOR]

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a canonical member of a group of dioxins which are byproducts of industrial combustion and are dangerous environmental pollutants. TCDD has been shown to cause several abnormalities in humans and wildlife, and recently, some dioxins have been found to activate platelets. However, TCDD-mediated platelet activation pathways are elusive and virtually nothing is known about TCDD activation of fish thrombocytes. To investigate TCDD effect on thrombocyte function, we tested zebrafish blood in presence of TCDD using a thrombocyte functional assay. We found that TCDD activated thrombocytes. Further experiments showed that thrombocytes of fish treated with TCDD formed both aggregates and filopodia. To investigate the mechanism of TCDD-mediated activation of thrombocytes we used inhibitors for Gq, cyclooxygenase-1, aryl hydrocarbon receptor (AHR), c-src, Akt, and ERK1/2. We found that TCDD induces AHR which activates c-src and signals the activation of Akt and ERK1/2 which are ultimately involved in generation of thromboxane A2. Furthermore, we found that ADP potentiates TCDD action, which led to the discovery that ADP itself activates AHR in the absence of TCDD. Taken together, these results resolved the pathway of TCDD activation of thrombocytes and led to the finding that ADP is an activator of AHR. [ABSTRACT FROM AUTHOR]

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used medications as analgesics and antipyretics. Currently, there is a growing interest in their antitumor activity and their ability to reduce the risk and mortality of several cancers. While several studies revealed the ability of NSAIDs to induce apoptosis and inhibit angiogenesis in cancer cells, their exact anticancer mechanism is not fully understood. However, both cyclooxygenase (COX)-dependent and -independent pathways were reported to have a role. In an attempt to develop new anticancer agents, a series of diphenylthiazole substituted thiazolidinone derivatives was synthesized and evaluated for their anticancer activity against a panel of cancer cell lines. Additionally, the inhibitory activity of the synthesized derivatives against COX enzymes was investigated as a potential mechanism for the anticancer activity. Cytotoxicity assay results showed that compounds 15b and 16b were the most potent anticancer agents with half maximal inhibitory concentrations (IC 50 ) between 8.88 and 19.25 μM against five different human cancer cell lines. Interestingly, COX inhibition assay results were in agreement with that of the cytotoxicity assays where the most potent anticancer compounds showed good COX-2 inhibition comparable to that of celecoxib. Further support to our results were gained by the docking studies which suggested the ability of compound 15b to bind into COX-2 enzyme with low energy scores. Collectively, these results demonstrated the promising activity of the newly designed compounds as leads for subsequent development into potential anticancer agents. [ABSTRACT FROM AUTHOR]

Abstract: Parkinson''s disease (PD) is known to be a chronic and progressive neurodegenerative disease caused by a selective degeneration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). A large body of experimental evidence indicates that the factors involved in the pathogenesis of this disease are several, occurring inside and outside the DAergic neuron. Recently, the role of the neuron–glia interaction and the inflammatory process, in particular, has been the object of intense study by the research community. It seems to represent a new therapeutic approach opportunity for this neurological disorder. Indeed, it has been demonstrated that the cyclooxygenase type 2 (COX-2) is up-regulated in SNc DAergic neurons in both PD patients and animal models of PD and, furthermore, non-steroidal anti-inflammatory drugs (NSAIDs) pre-treatment protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6 hydroxydopamine (6-OHDA)-induced nigro-striatal dopamine degeneration. Moreover, recent epidemiological studies have revealed that the risk of developing PD is reduced in humans who make therapeutical use of NSAIDs. Consequently, it is hypothesized that they might delay or prevent the onset of PD. However, whether or not these common drugs may also be of benefit to those individuals who already have Parkinson''s disease has not as yet been shown. In this paper, evidence relating to the protective effects of aspirin or other NSAIDs on DAergic neurons in animal models of Parkinson''s disease will be discussed. In addition, the pharmacological mechanisms by which these molecules can exert their neuroprotective effects will be reviewed. Finally, epidemiological data exploring the effectiveness of NSAIDs in the prevention of PD and their possible use as adjuvants in the therapy of this neurodegenerative disease will also be examined. [Copyright &y& Elsevier]

Abstract: Cyclooxygenase (COX) 2 is expressed in atherosclerotic lesions. We have previously reported that selective inhibition of COX-2 reduces early atherosclerosis in LDLR deficient mice. To examine the role of COX-2 in atherosclerosis in other mouse models, we studied the effects of selective COX-2 inhibition (by rofecoxib and NS-398) and nonselective COX inhibition (by indomethacin) on early atherosclerotic lesion formation in apolipoprotein E-deficient (apoE–/–) mice. Selective COX-2 and nonselective COX inhibition reduced atherosclerosis in female apoE–/– mice by 35–38% and 38–51% in the proximal and en face aortas, respectively. Next we investigated the role of macrophage COX-2 by transplanting COX-2–/– fetal liver cells into C57BL/6 mice and challenging the mice with an atherogenic diet. Genetic deletion of COX-2 from hematopoietic cells reduced atherosclerosis by 51%. In addition, LPS activated COX-2–/– macrophages had decreased expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNFα). The results demonstrate that selective inhibition of COX-2 and elimination of COX-2 from macrophages significantly reduces early atherosclerotic lesion formation in apoE-deficient and C57BL/6 mice. These results are compatible with COX-2 expression by macrophages having a proatherogenic role, and support the potential of anti-inflammatory therapeutic approaches for atherosclerosis. [Copyright &y& Elsevier]

Background. Postoperative ileus (PI) is a common surgical complication, the treatment of which consists of supportive measures.Aim. The effects of several cyclooxygenase (COX) inhibitors and their interaction with l-arginine/nitric oxide synthase (NOS) pathway were tested in a rat PI model.Methods. Intestinal transit was measured as Evans blue migration after skin incision, laparotomy, or laparotomy followed by evisceration and gut handling.Results. In contrast to a selective inducible NOS (iNOS) blocker, l-N6-(1-iminoethyl)lysine hydrochloride (L-NIL), Nω-nitro-l-arginine methyl ester (L-NAME) reversed the additional inhibitory effects of gut manipulation after laparotomy on the gastrointestinal transit (GI) in a dose-dependent, l-arginine-sensitive manner. Laparotomy and manipulations of small intestine increased blood plasma nitrites and nitrates level (NOx), an effect preventable by L-NAME. Indomethacin, resveratrol (selective COX-1 blocker), and COX-2 antagonists, nimesulide, NS-398, DuP-697, and L-752860, attenuated the additional inhibitory effects of gut manipulation following laparotomy in a dose-dependent manner. In contrast, only nimesulide, NS-398, DuP-697, and L-752860 partly, but significantly, reversed the effects of laparotomy on the intestinal transit. Administration of L-NAME subsequent to COX inhibitors abolished the salutary effects of the latter, implying that at least the synthesis of either NO or prostanoids must remain unaffected to enable a return of GI transit during the postoperative period.Conclusion. In addition to NO synthesized by constitutive NOS (cNOS), prostaglandins produced by both COX-1 and COX-2 participate in the pathogenesis of PI, albeit in different pathological mechanisms. Thus laparotomy stimulated COX-2 activity, whereas gut manipulation led to an excessive cNOS activity and prostaglandin synthesis by COX-1. [Copyright &y& Elsevier]

• A novel class of trisubstituted pyrazolines as PDE5 inhibitors was discovered. • The compounds were developed inspired by the off-target activity of celecoxib against PDE5. • The developed compounds showed promising selectivity profile. • The developed compounds could increase intracellular cGMP levels in HEK293 cells. Celecoxib, is a selective cyclooxygenase-2 (COX2) inhibitor with a 1,5-diaryl pyrazole scaffold. Celecoxib has a better safety profile compared to other COX2 inhibitors having side effects of systemic hypertension and thromboembolic complications. This may be partly attributed to an off-target activity involving phosphodiesterase 5 (PDE5) inhibition and the potentiation of NO/cGMP signalling allowing coronary vasodilation and aortic relaxation. Inspired by the structure of celecoxib, we synthesized a chemically diverse series of compounds containing a 1,3,5-trisubstituted pyrazoline scaffold to improve PDE5 inhibitory potency, while eliminating COX2 inhibitory activity. SAR studies for PDE5 inhibition revealed an essential role for a carboxylic acid functionality at the 1-phenyl and the importance of the non-planar pyrazoline core over the planar pyrazole with the 5-phenyl moiety tolerating a range of substituents. These modifications led to new PDE5 inhibitors with approximately 20-fold improved potency to inhibit PDE5 and no COX-2 inhibitory activity compared with celecoxib. PDE isozyme profiling of compound 11 revealed a favorable selectivity profile. These results suggest that trisubstituted pyrazolines provide a promising scaffold for further chemical optimization to identify novel PDE5 inhibitors with potential for less side effects compared with available PDE5 inhibitors used for the treatment of penile erectile dysfunction and pulmonary hypertension. [ABSTRACT FROM AUTHOR]

• Rational design and synthesis of novel derivatives of pyrrolo[3,4- d pyridazinone have been described. • All new derivatives inhibit both cyclooxygenase enzymes. • Comprehensive in vitro and in silico studies confirmed that the most potent is 7b. • Novel Mannich base derivatives prevent DNA strand breaks caused by an increase in intracellular ROS. • All new derivatives bind to the active site of the enzyme in a way very similar to meloxicam. Novel Mannich base analogues of pyrrolo[3,4- d pyridazinone 7a , b - 13a , b are designed and synthesized as potential anti-inflammatory agents. The title compounds are obtained via convenient one-pot synthesis with good yields. Their structures and properties are described by spectroscopic techniques and elemental analyses. The aim of this study is to evaluate the inhibitory activity of the new derivatives against both cyclooxygenase isoforms COX1 and COX2 as well as their cytotoxicity. The results clearly indicate that the tested compounds 7a , b - 13a , b are not toxic, all show better affinity towards isoform COX-2, and some of them act as selective COX-2 inhibitors. Moreover, every examined derivative of pyrrolo[3,4- d pyridazinone demonstrates better inhibitory activity towards COX-2 and a superior COX-2/COX-1 selectivity ratio compared to the reference drug meloxicam. Molecular docking studies confirm that compounds 7a,b-13a,b preferably bind COX-2 and all of them bind to the active site of cyclooxygenase in a way very similar to meloxicam. Subsequently, taking into account that inflammation is strongly correlated with oxidative stress and both of these processes can potentiate each other, synthesized Mannich bases are evaluated for potential antioxidant activity. Most of the investigated derivatives reduce induced oxidative and nitrosative stress. Moreover, compounds 7a , b , 8a , 10a,b , 11b , 12a , b - 13a , b protect chromatin from oxidative stress and decrease the number of DNA strand breaks caused by intracellular growth of free radicals. Finally, a study of the binding mechanism between compounds 7a , b - 13a , b and bovine serum albumin (BSA) was carried out. According to spectroscopic and molecular docking studies, all examined derivatives interact with BSA, which suggests their potential long half-life in vivo. [ABSTRACT FROM AUTHOR]

• Efficient synthesis of 1,3,4-thiadiazole-4-thiazolidinone hybrids modified at the 5th position of thiadiazole and/or thiazolidinone. • The in vitro and in vivo anti-inflammatory activities were determined. These activities affected significantly by the size of the substituent at the 5th position. • New compounds with potent dual COX-2/15-LOX inhibition, good in vivo activity and good gastric safety profile were obtained. Herin we report the design, synthesis, full characterization and biological investigation of new 15-LOX/COX dual inhibitors based on 1,3-thiazolidin-4-one (15-lipoxygenase pharmacophore) and 1,3,4-thiadiazole (COX pharmacophore) scaffolds. This series of molecular modifications is an extension of a previously reported series to further explore the structural activity relationship. Compounds 3a , 4e , 4n , 4q, 7 and 8 capable of inhibiting 15-LOX at (2.74, 4.2, 3.41, 10.21, 3.71 and 3.36 µM, respectively) and COX-2 at (0.32, 0.28, 0.28, 0.1, 0.28 and 0.27 µM, respectively). The results revealed that binding to 15-LOX and COX is sensitive to the bulkiness of the substituents at the 5 positions. 15-LOX bind better with small substituents, while COXs bind better with bulky substituents. Compounds 3a , 4r and 4q showed comparable in vivo anti-inflammatory activity to the reference drug (celecoxib). The ulcer liability test showed no sign of ulceration which ensures the safe gastric profile. Docking study was performed to explore the possible mode of interaction of the new compounds with the active site of human 15-LOX and COX-2. This study discloses some structural features for binding to 15-LOX and COX, thus pave the way to design anti-inflammatory agents with balanced dual inhibition of these enzymes. [ABSTRACT FROM AUTHOR]

To conduct a comprehensive systematic meta-analysis investigating the association of nonsteroidal anti-inflammatory drugs (NSAIDs) and their subtypes with skin cancer (SC) and its subclasses (basal cell carcinoma BCC; squamous cell carcinoma SCC; melanoma; nonmelanoma skin cancer NMSC) in general, American and European populations. PubMed, Embase, the Cochrane Library, the China National Knowledge Infrastructure and ClinicalTrials.gov were searched up to 24 February 2019. Pooled effect sizes and 95% confidence intervals were used to estimate associations. Results based on 26 original studies including 223,619 cases and 1,398,507 controls showed both NSAIDs and nonselective Cyclooxygenase (COX) inhibitors to be statistically significantly associated with a reduced risk of SC, BCC, SCC and NMSC but not with melanoma. Conversely, no association was observed between selective Cyclooxygenase 2 (COX-2) inhibitors and SC or its subclasses. Further subgroup analysis showed that the results analyzed for American populations were almost the same as those for the general population. For European populations, neither NSAIDs nor its subtypes correlated significantly with susceptibility to SC or its subclasses. The use of NSAIDs might reduce the risk of SC, but many factors including study population, drug subtype, and disease subclass affect the significance of the association. [ABSTRACT FROM AUTHOR]

• The investigational drug IND has been patented with USPTO. • Plasma protein binding has a major role in drug therapy specifically the pharmacokinetics and pharmacodynamics. • The interaction between IND and BSA has been investigated by using spectroscopic methods. • Molecular docking studies suggested that IND binds mainly to the subdomain IIA of BSA. • The experimental results will be helpful in preclinical drug development of IND. The indole derivative 2-(5-methoxy-2-methyl-1H-indol-3-yl)-N'-[(E)-(3-nitrophenyl) methylidene]acetohydrazide (IND) was synthesized for its therapeutic potential to inhibit cyclooxygenase (COX)-II. Binding if IND to bovine serum albumin (BSA) was investigated was because most drugs bind to serum albumin in -vivo. Fluorescence, UV–vis spectrophotometry and molecular modeling methodologies were employed for studying the interaction mechanism. The intrinsic fluorescence of BSA was quenched by BSA and the quenching mechanism involved was static quenching. The binding constants between IND and BSA at the three studied temperatures (298, 301 and 306 K) were 1.09 × 105, 4.36 × 104 and 1.23 × 104 L mol−1 respectively. The most likely site for binding IND to BSA was Site I (subdomain IIA). The analysis of thermodynamic parameter revealed the involvement of hydrogen bonding and van der Waals forces in the IND-BSA interaction. Synchronous fluorescence spectroscopic (SFS) and UV–vis spectrophotometric studies suggested conformational change in BSA molecule post interaction to IND. Molecular docking and the experimental results corroborated one another. The study can prove as an insight for future IND drug development. [ABSTRACT FROM AUTHOR]