Tailored quinoline hybrids as promising COX-2/15-LOX dual inhibitors endowed with diverse safety profile: Design, synthesis, SAR, and histopathological study.

Complications of the worldwide use of non-steroidal anti-inflammatory drugs (NSAIDs) sparked scientists to design novel harmless alternatives as an urgent need. So, a unique hybridization tactic of quinoline/pyrazole/thioamide (4a-c) has been rationalized and synthesized as potential COX-2/15-LOX dual inhibitors, utilizing relevant reported studies on these pharmacophores. Moreover, we extended these preceding hybrids into more varied functionality, bearing crucial thiazole scaffolds(5a-l). All the synthesized hybrids were evaluatedin vitroas COX-2/15-LOX dual inhibitors. Initially, series4a-cexhibited significant potency towards 15-LOX inhibition (IC50 = 5.454-4.509 µM) compared to meclofenamate sodium (IC50 = 3.837 µM). Moreover, they revealed reasonable inhibitory activities against the COX-2 enzyme in comparison to celecoxib.Otherwise, conjugates 5a-ldisclosed marked inhibitory activity against 15-LOX and strong inhibitory to COX-2. In particular, hybrids5d(IC50 = 0.239 µM, SI = 8.95), 5h(IC50 = 0.234 µM, SI = 20.35) and 5l (IC50 = 0.201 µM, SI = 14.42) revealed more potency and selectivity outperforming celecoxib (IC50 = 0.512 µM, SI = 4.28). In addition, the most potentcompounds, 4a, 5d, 5h, and 5l have been elected for further in vivoevaluation and displayed potent inhibition of edema in the carrageenan-induced rat paw edema test that surpassed indomethacin. Further, compounds5d, 5h, and 5l decreased serum inflammatory markers including oxidative biomarkersiNO, and pro-inflammatory mediators cytokines like TNF-α, IL-6, and PGE. Ulcerogenic liability for tested compounds demonstrated obvious gastric mucosal safety. Furthermore, a histopathological study for compound 5l suggested a confirmatory comprehensive safety profile for stomach, kidney, and heart tissues. Docking and drug-likeness studies offered a good convention with the obtained biological investigation.

Investigating the Anti-tumor and Apoptosis-inducing Effects of Coumarin Derivatives as Potent 15-Lipoxygenase Inhibitors on PC-3 Prostate Cancer Cells.

INTRODUCTION: Prostate cancer is the second most prevalent cancer among men. Despite different treatments, including surgery, chemotherapy, radiation therapy, hormone therapy and immunotherapy for this disease, patients ultimately progress to advanced states. Thus, there is a need for new treatment options targeting cell growth and apoptosis to better control the proliferation and metastasis of these cells. There are many reports indicating overexpression of the 15-lipoxygenase-1 (15-LOX-1) enzyme in prostate tumors. Studies have also shown that inhibition of this enzyme prevents the progression of prostate cancer. OBJECTIVE: This study was conducted to assess the anti-cancer properties of some coumarin derivatives as possible 15- LOX-1 inhibitors, on PC-3 prostate cancer cells. METHODS: In this study, the activity of 15-LOX-1 was evaluated in PC-3 cells by a spectrophotometric assay. In addition, due to high similarity between the 15-LOX-1 and soybean 15-lipoxygenase (SLO) (L1; EC 1, 13, 11, 12) active sites, the soybean SLO was used to investigate inhibitory effects of synthetic coumarin compounds 8- isopentenyloxycoumarin (8-IC), 8-isopentenyloxy-3-carboxycoumarin (8-ICC), 8-geranyloxycoumarin (8-GC), 8- geranyloxy-3-carboxycoumarin (8-GCC), and 8-farnesyloxy-3-carboxycoumarin (8-FCC) on this enzyme. Moreover, the cytotoxic and anticancer effects of the coumarin compounds were examined on PC-3 (Prostate Cancer) and HDF-1 (Human Dermal Fibroblast) cells by alamarBlue assay. Finally, apoptosis-inducing effects of all synthetic compounds were determined by flow cytometry. RESULTS: The IC50 values obtained by the alamarBlue test revealed that 8-IC, 8-GC and 8-GCC had cytotoxic effects on PC-3 cells. Treating both PC-3 and HDF-1 cells with 8-ICC and 8-FCC did not significantly reduce cell number. Furthermore, the IC50 values of 8-IC on HDF-1 cells showed cytotoxic effects, while treating these cells with 8-GC and 8- GCC did not show any significant cytotoxicity on these normal human fibroblasts. Assessing the ability of 4-MMPB (as a specific inhibitor of 15-LOX-1), 8-GC, and 8-GCC compounds to inhibit SLO revealed that these compounds exerted strong 15-LOX-1 inhibitory activity, while 8-IC and 8-FCC had a weak inhibitory effect and also 8-ICC showed no inhibitory effect on SLO enzyme. In addition, flow cytometric analysis by FITC (fluorescein isothiocyanate)- annexin V and propidium iodide showed that treatment with IC50 values of 8-GC and 8-GCC induced apoptosis in 35.2% and 30.8% of PC-3 cells, respectively. CONCLUSION: Thus, 8-GC and 8-GCC can be introduced as effective anticancer agents with apoptosis-inducing properties. Furthermore, our results suggest that the cytotoxic effects of these compounds might be related to the inhibition of 15-LOX-1 enzyme in PC-3 cells. On the other hand, the cytotoxic effects of 8-IC might be due to the inhibition of other signaling pathways in PC-3 cells. However, further in vivo experiments are required to determine the exact mechanisms involved in the anticancer effects of these coumarin compounds.

Highly potent and selective 5-lipoxygenase inhibition by new, simple heteroaryl-substituted catechols for treatment of inflammation.

5-Lipoxygenase (LO) catalyzes the first steps in the formation of pro-inflammatory leukotrienes (LT) that are pivotal lipid mediators contributing to allergic reactions and inflammatory disorders. Based on its key role in LT biosynthesis, 5-LO is an attractive drug target, demanding for effective and selective inhibitors with efficacy in vivo, which however, are still rare. Encouraged by the recent identification of the catechol 4-(3,4-dihydroxyphenyl)dibenzofuran 1 as 5-LO inhibitor, simple structural modifications were made to yield even more effective and selective catechol derivatives. Within this new series, the two most potent compounds 3,4-dihydroxy-3'-phenoxybiphenyl (6b) and 2-(3,4-dihydroxyphenyl)benzo[b]thiophene (6d) potently inhibited human 5-LO in cell-free (IC506b and 6d = 20 nM) and cell-based assays (IC506b = 70 nM, 6d = 60 nM). Inhibition of 5-LO was reversible, unaffected by exogenously added substrate arachidonic acid, and not primarily mediated via radical scavenging and antioxidant activities. Functional 5-LO mutants expressed in HEK293 cells were still prone to inhibition by 6b and 6d, and docking simulations revealed distinct binding of the catechol moiety to 5-LO at an allosteric site. Analysis of 5-LO nuclear membrane translocation and intracellular Ca2+ mobilization revealed that these 5-LO-activating events are hardly affected by the catechols. Importantly, the high inhibitory potency of 6b and 6d was confirmed in human blood and in a murine zymosan-induced peritonitis model in vivo. Our results enclose these novel catechol derivatives as highly potent, novel type inhibitors of 5-LO with high selectivity and with marked effectiveness under pathophysiological conditions.

Discovery and Optimization of Indoline-Based Compounds as Dual 5-LOX/sEH Inhibitors: In Vitro and In Vivo Anti-Inflammatory Characterization.

The design of multitarget drugs represents a promising strategy in medicinal chemistry and seems particularly suitable for the discovery of anti-inflammatory drugs. Here, we describe the identification of an indoline-based compound inhibiting both 5-lipoxygenase (5-LOX) and soluble epoxide hydrolase (sEH). In silico analysis of an in-house library identified nine compounds as potential 5-LOX inhibitors. Enzymatic and cellular assays revealed the indoline derivative 43 as a notable 5-LOX inhibitor, guiding the design of new analogues. These compounds underwent extensive in vitro investigation revealing dual 5-LOX/sEH inhibitors, with 73 showing the most promising activity (IC50s of 0.41 ± 0.01 and 0.43 ± 0.10 µM for 5-LOX and sEH, respectively). When challenged in vivo in zymosan-induced peritonitis and experimental asthma in mice, compound 73 showed remarkable anti-inflammatory efficacy. These results pave the way for the rational design of 5-LOX/sEH dual inhibitors and for further investigation of their potential use as anti-inflammatory agents.

8-Geranyloxycarbostyril as a potent 15-LOX-1 inhibitor showed great anti-tumor effects against prostate cancer.

Carbostyrils are quinolone derivatives, with possible growth inhibition properties on cancer cells. Unlike many tumors, 15-Lipoxygenase-1 (15-LOX-1) is highly expressed in prostate cancer (PCa) cells and has oncogenic properties. Here, with the hypothesis that 6-, 7- and 8-geranyloxycarbostyril (GQ) have inhibitory properties on 15-LOX-1, their effects were assessed on PCa cells. Their cytotoxic effects were evaluated by MTT assay and mechanism of cell death was investigated using annexin V/PI staining. Finally, the anti-tumor properties of 8-GQ were assessed in immunocompromised C57BL/6 mice bearing human PCa cells. Accordingly, these compounds could effectively inhibit 15-LOX activity in PCa cells. MTT and flow cytometry tests confirmed their toxic effects on PCa cells, with no significant toxicity on normal cells, and apoptosis was the main mechanism of cell death. In vivo results indicated that use of 8-GQ at 50 mg/kg had stronger anti-tumor effects than 5 mg/kg cisplatin, with fewer side effects on normal tissues. Therefore, 8-GQ can be introduced as a potential drug candidate with 15-LOX-1 inhibitory potency, which can be effective in treatment of prostate cancer, and should be considered for further drug screening investigations.

Licofelone, a potent COX/5-LOX inhibitor and a novel option for treatment of neurological disorders.

Neurological disorders result in disability and morbidity. Neuroinflammation is a key factor involved in progression or resolution of a series of neurological disorders like Huntington disease (HD), Parkinson's disease (PD), Alzheimer's disease (AD), Spinal Cord Injury (SCI), and Seizure. Thereby, anti-inflammatory drugs have been developed to improve the neurodegenerative impairments. Licofelone is an approved osteoarthritis drug that inhibits both the COX (cyclooxygenase) and 5-LOX (lipoxygenase) pathways. Licofelone has pain-relieving and anti-inflammatory effects and it was shown to have neuroprotective properties in the central nervous system, which is implicated in its regulatory effect on the COX/5-LOX pathway, inflammatory cytokines, and immune responses. In this study, we briefly review the various features of neurological disorders and the function of COX/LOX in their flare up and current pharmacological products for their management. Moreover, this review attempts to summarize potential therapeutics that target the immune responses within the central nervous system. A better understanding of the interactions between Licofelone and the nervous systems will be crucial to demonstrate the possible efficacy of Licofelone in neurological disorders.

Antioxidant Serine-(NSAID) Hybrids with Anti-Inflammatory and Hypolipidemic Potency.

A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC50 3.4 µΜ and 2.8 µΜ), several times more potent than the reference Trolox (IC50 25 µΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37-67% at 150 µmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC50 13 µΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 µmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions.

ALOX5-5-HETE promotes gastric cancer growth and alleviates chemotherapy toxicity via MEK/ERK activation.

BACKGROUND: Recent studies highlight the regulatory role of arachidonate lipoxygenase5 (Alox5) and its metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) in cancer tumorigenesis and progression. In this study, we analyzed the expression, biological function and the downstream signaling of Alox5 in gastric cancer. METHODS: Alox5 protein levels were measured using IHC and ELISA. Growth, migration and survival assays were performed. Phosphorylation of molecules involved in growth and survival signaling were analyzed by WB. Analysis of variance and t-test were used for statistic analysis. RESULTS: Alox5 and 5-HETE levels were upregulated in gastric cancer patients. ALOX5 overexpression or 5-HETE addition activates gastric cancer cells and reduces chemotherapy's efficacy. In contrast, ALOX5 inhibition via genetic and pharmacological approaches suppresses gastric cancer cells and enhances chemotherapy's efficacy. In addition, Alox5 inhibition led to suppression of ERK-mediated signaling pathways whereas ALOX5-5-HETE activates ERK-mediated signaling in gastric cancer cells. CONCLUSIONS: Our work demonstrates the critical role of ALOX5-5-HETE in gastric cancer and provides pre-clinical evidence to initialize clinical trial using zileuton in combination with chemotherapy for treating gastric cancer.

Lipoxygenase inhibitor ML351 dysregulated an innate inflammatory response leading to impaired cardiac repair in acute heart failure.

The presistent increase of 12/15 lipoxygenase enzyme activity is correlated with uncontrolled inflammation, leading to organ dysfunction. ML351, a potent 12/15 lipoxygenase (12/15LOX) inhibitor, was reported to reduce infarct size and inflammation in a murine ischemic stroke model. In the presented work, we have applied three complementary experimental approaches, in-vitro, ex-vivo, and in-vivo, to determine whether pharmacological inhibition of 12/15LOX could dampen the inflammatory response in adult mice after Kdo2-Lipid A (KLA) as an endotoxin stimulator or post myocardial infarction (MI). Male C57BL/6 (8-12 weeks) mice were subjected to permanent coronary ligation thereby inducing acute heart failure (MI-d1 and MI-d5) for in-vivo studies. 12/15LOX antagonist ML351 (50 mg/kg) was subcutaneously injected 2 h post-MI, while MI-controls received saline. For ex-vivo experiments, ML351 (25 mg/kg) was injected as bolus after 5 min of inflammatory stimulus (KLA 1 µg/g) injection. Peritoneal macrophages (PMɸ) were harvested after 4 h post KLA. For in-vitro studies, PMɸ were treated with KLA (100 ng/mL), ML351 (10 µM), or KLA + ML351 for 4 h, and inflammatory response was evaluated. In-vivo, 5LOX expression was reduced after ML351 administration, inducing a compensatory increase of 12LOX that sensitized PMɸ toward a proinflammatory state. This was marked by higher inflammatory cytokines and dysregulation of the splenocardiac axis post-MI. ML351 treatment increased CD11b+ and Ly6Chigh populations in spleen and Ly6G+ population in heart, with a decrease in F4/80+ macrophage population at MI-d1. In-vitro results indicated that ML351 suppressed initiation of inflammation while ex-vivo results suggested ML351 overactivated inflammation consequently delaying the resolution process. Collectively, in-vitro, ex-vivo, and in-vivo results indicated that pharmacological blockade of lipoxygenases using ML351 impaired initiation of inflammation thereby dysregulated acute immune response in cardiac repair.

Mechanistic evaluation of a novel cyclohexenone derivative's functionality against nociception and inflammation: An in-vitro, in-vivo and in-silico approach.

The synthesis of a novel cyclohexanone derivative (CHD; Ethyl 6-(4-metohxyphenyl)-2-oxo-4-phenylcyclohexe-3-enecarboxylate) was described and the subsequent aim was to perform an in vitro, in vivo and in silico pharmacological evaluation as a putative anti-nociceptive and anti-inflammatory agent in mice. Initial in vitro studies revealed that CHD inhibited both cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) enzymes and it also reduced mRNA expression of COX-2 and the pro-inflammatory cytokines TNF-α and IL-1ß. It was then shown that CHD dose dependently inhibited chemically induced tonic nociception in the abdominal constriction assay and also phasic thermal nociception (i.e. anti-nociception) in the hot plate and tail immersion tests in comparison with aspirin and tramadol respectively. The thermal test outcomes indicated a possible moderate centrally mediated anti-nociception which, in the case of the hot plate test, was pentylenetetrazole (PTZ) and naloxone reversible, implicating GABAergic and opioidergic mechanisms. CHD was also effective against both the neurogenic and inflammatory mediator phases induced in the formalin test and it also disclosed anti-inflammatory activity against the phlogistic agents, carrageenan, serotonin, histamine and xylene compared with standard drugs in edema volume tests. In silico studies indicated that CHD possessed preferential affinity for GABAA, opioid and COX-2 target sites and this was supported by molecular dynamic simulations where computation of free energy of binding also favored the formation of stable complexes with these sites. These findings suggest that CHD has prospective anti-nociceptive and anti-inflammatory properties, probably mediated through GABAergic and opioidergic interactions supplemented by COX-2 and 5-LOX enzyme inhibition in addition to reducing pro-inflammatory cytokine expression. CHD may therefore possess potentially beneficial therapeutic effectiveness in the management of inflammation and pain.

Novel 1,2,4-triazine-quinoline hybrids: The privileged scaffolds as potent multi-target inhibitors of LPS-induced inflammatory response via dual COX-2 and 15-LOX inhibition.

Based on the observed pharmacophoric structural features for the reported dual COX/15-LOX inhibitors and inspired by the abundance of COX/LOX inhibitory activities reported for the 1,2,4-triazine and quinoline scaffolds, we designed and synthesized novel 1,2,4-triazine-quinoline hybrids (8a-n). The synthesized hybrids were evaluated in vitro as dual COXs/15-LOX inhibitors. The new triazine-quinoline hybrids (8a-n) exhibited potent COX-2 inhibitory profiles (IC50 = 0.047-0.32 µM, SI âˆ¼ 20.6-265.9) compared to celecoxib (IC50 = 0.045 µM, SI âˆ¼ 326). Moreover, they revealed potent inhibitory activities against 15-LOX enzyme compared to reference quercetin (IC50 = 1.81-3.60 vs. 3.34 µM). Hybrid 8e was the most potent and selective dual COX-2/15-LOX inhibitor (COX-2 IC50 = 0.047 µM, SI = 265.9, 15-LOX IC50 = 1.81 µM). These hybrids were further challenged by their ability to inhibit NO, ROS, TNF-α, IL-6 inflammatory mediators, and 15-LOX product, 15-HETE, production in LPS-activated RAW 264.7 macrophages cells. Compound 8e was the most potent hybrid in reducing ROS and 15-HETE levels showing IC50 values of 1.02 µM (11-fold more potent than that of celecoxib, IC50 = 11.75 µM) and 0.17 µM (about 43 times more potent than celecoxib, IC50 = 7.46 µM), respectively. Hybrid 8h exhibited an outstanding TNF-α inhibition with IC50 value of 0.40 µM which was about 25 times more potent than that of celecoxib and diclofenac (IC50 = 10.69 and 10.27 µM, respectively). Docking study of the synthesized hybrids into the active sites of COX-2 and 15-LOX enzymes ensures their favored binding affinity. To our knowledge, herein we reported the first 1,2,4-triazine-quinoline hybrids as dual COX/15-LOX inhibitors.

The Manipulation of the Lipid Mediator Metabolism as Adjunct Host-Directed Therapy in Tuberculosis.

Host-directed therapies (HDTs) enhance the host response to tuberculosis (TB) infection to reduce disease severity. For instance, the manipulation of lipid mediator production diminishes the hyperactive immune response which is a known pathological feature of TB that generates lung tissue damage. Non-steroidal anti-inflammatory drugs (NSAIDs) and omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) are examples of such HDTs. In this mini-review, we recapitulate the literature available on the effects of NSAIDs and n-3 LCPUFA in TB as well as the immunological pathways underpinning these effects. Many NSAIDs have a great deal of data describing their effects and safety and in many jurisdictions are inexpensive, and sold over the counter in neighborhood convenience stores and supermarkets. The potential benefits of NSAIDs in TB are well-documented in pre-clinical studies. The reduction of pro-inflammatory lipid mediator production by inhibiting cyclooxygenase (COX) pathways with NSAIDs has been found to improve lung histopathology, bacterial control, and survival. Additionally, n-3 LCPUFA and its novel bioactive metabolites produced by COX and lipoxygenase (LOX) have been identified as safe and effective pro-resolving and antibacterial pharmaconutrients. Nevertheless, heterogeneous results have been reported in pre-clinical TB studies. Recently, the importance of the correct timing of NSAIDs and n-3 LCPUFA administration in TB has also been highlighted. This mini-review will provide a better understanding of the potential contribution of these therapies toward reducing inflammatory lung damage and improving bactericidal activity, especially during later stages of TB infection. It further highlights that clinical trials are required to confirm benefit and safety in TB patients.

Effects of ML351 and tissue plasminogen activator combination therapy in a rat model of focal embolic stroke.

Thrombolytic stroke therapy with tissue plasminogen activator (tPA) is limited by risks of hemorrhagic transformation (HT). We have reported that a new 12/15-lipoxygenase (12/15-LOX) inhibitor ML351 reduced tPA related HT in mice subjected to experimental stroke under anticoagulation. In this study, we asked whether ML351 can ameliorate tPA induced HT in an embolic stroke model. Rats were subjected to embolic middle cerebral artery occlusion with 2 or 3 hr ischemia and tPA infusion, with or without ML351. Regional cerebral blood flow was monitored 2 hr after ischemia and continuously monitored for 1 hr after treatment for determining reperfusion. Hemoglobin was determined in brain homogenates and infarct volume was quantified at 24 hr after stroke.12/15-LOX, cluster of differentiation 68(CD68), immunoglobulin G (IgG), and tight junction proteins expression was detected by immunohistochemistry. ML351 significantly reduced tPA related hemorrhage after stroke without affecting its thrombolytic efficacy. ML351 also reduced blood-brain barrier disruption and improved preservation of junction proteins. ML351 and tPA combination improved neurological deficit of rats even though ML351 did not further reduce the infarct volume compared to tPA alone treated animals. Pro-inflammatory cytokines were suppressed by ML351 both in vivo and in vitro experiments. We further showed that ML351 suppressed the expression of c-Jun-N-terminal kinase (JNK) in brains and microglia cultures, whereas exogenous 12-HETE attenuated this effect in vitro. In conclusion, ML351 and tPA combination therapy is beneficial in ameliorating HT after ischemic stroke. This protective effect is probably because of 12/15-LOX inhibition and suppression of JNK-mediated microglia/macrophage activation.

Synthesis, characterization and anti-inflammatory properties of karanjin (Pongamia pinnata seed) and its derivatives.

Karanja (Pongamia pinnata) is a medicinal tree used in the Indian traditional ayurvedic system for treating several ailments. The seeds contain a unique furano-flavonoid karanjin, which has shown to possess many medicinal properties. Its usage at the clinical level is affected due to poor solubility and absorption. In the present investigation, molecular modifications of karanjin were attempted and evaluated their effect on anti-inflammatory activity. Firstly, Karanja ketone was obtained from karanjin by hydrolysis, and it was converted into karanja ketone oxime. The oxime undergoes Beckmann rearrangement and cyclized to yield furano benzoxazole (karanja oxazole). The new derivatives were purified with >95% purity (HPLC) and spectrally characterized (HR-MS, FTIR, and NMR). Among the test compounds, karanja ketone oxime exhibited higher antioxidant activity with an IC50 value of 360 µg/ml (DPPH). Soy lipoxygenase-1 (LOX-1) inhibitory activity of oxime was higher (IC50 = 65.4 µM) than other compounds. Fluorescence studies showed that oxime had higher quenching capacity with a Qmax of 76.3% and a binding constant of 0.9 × 105 M-1 for soy LOX-1. In-silico interaction studies showed that karanja ketone oxime had the least binding energy of -5.76 kcal/mol with LOX-1 by forming two hydrogen bonds with hydrophobic amino acids Leu 390 and Gly 392. The compounds were evaluated for their acute anti-inflammatory activity by the paw and ear edema in the rat model. Karanjin inhibits paw edema and ear edema by 34.13% and 51.13%, respectively, whereas the derivatives inhibited by 45-57 % and 70-76.8%. This study reports a rational approach to synthesize karanjin derivatives with considerable anti-inflammatory properties, both in-vitro and in-vivo.

Synthesis, in vivo anti-inflammatory, COX-1/COX-2 and 5-LOX inhibitory activities of new 2,3,4-trisubstituted thiophene derivatives.

New series of thiophene derivatives were synthesized and evaluated for their in vivo anti-inflammatory activity using carrageenan-induced paw edema model. The most active in vivo anti-inflammatory compounds 5b, 11b, 14c, 18c, 19c and 20d were further evaluated for their in vitro COX-1/COX-2 and 5-LOX inhibitory activities. The in vitro assay results revealed that the N-(4-(4-chlorophenyl)-3-cyanothiophen-2-yl)-2-morpholinoacetamide (5b) possesses the highest selectivity toward COX-2 (IC50 = 5.45 µM) with selectivity index value of 8.37 compared to celecoxib with COX-2 selectivity index value of 15.44. In addition, it showed acceptable 5-LOX inhibitory activity (IC50 = 4.33 µM) compared to NDGA (IC50 = 2.46 µM). Molecular modeling study was conducted to study the postulated binding of compound 5b into the active site of COX-2 and 5-LOX, and it revealed that 5b binds similarly to celecoxib and NDGA, respectively. Overall, the morpholinoacetamide-thiophene hybrid 5b could serve as a promising lead for further development of new potent anti-inflammatory agents that act as dual COX-2/5-LOX inhibitors.

Identification and development of thiazole leads as COX-2/5-LOX inhibitors through in-vitro and in-vivo biological evaluation for anti-inflammatory activity.

Treatment of inflammation using NSAIDs is coupled with a risk of severe gastric adverse events. Development of dual COX-2/5-LOX inhibitors turns out to be an imperative area devoted to safer NSAIDs. A series of thiourea, thiazole, and thiazolidene derivatives were synthesized by green synthetic approach and COX-1, COX-2 and 5-LOX inhibition screening resulted in the identification of a potent compound 6l with IC50 of 5.55 µM, 0.09 µM, and 0.38 µM respectively. Compound 6l made significant decrease (60.82%) in the carrageenan-induced edema in male Wistar rats. qRT-PCR analysis and determination of PGE2 and LTB4 in the rat paw tissues indicated that this thiazole based dual inhibitor significantly reduced the expression of COX-2 and 5-LOX genes besides the marked reduction in both PGE2 and LTB4 levels. The gastric safety profiling revealed an enhanced gastrointestinal safety of the compound 6l on histopathological examination. Molecular docking studies at COX-2 and 5-LOX active sites were consistent with biological studies by significant protein-ligand interaction. Besides, results of in-vitro PGE2 and LTB4 studies on RAW 264.7 cells as well as antioxidant studies were parallel to the dual inhibitory activity. The present investigations identify a promising lead having anti-inflammatory potential with an improved gastric safety profile.

Red-kerneled rice proanthocyanidin inhibits arachidonate 5-lipoxygenase and decreases psoriasis-like skin inflammation.

5-lipoxygenase is a key enzyme in the synthesis of leukotrienes from arachidonic acid. The produced leukotrienes are involved in inflammatory diseases including psoriasis, asthma, and atherosclerosis. A suitable 5-lipoxygenase inhibitor might be useful for preventing and improving the symptoms of leukotriene-related inflammatory diseases. Here, we investigate the mechanism underlying the anti-inflammatory effect of a proanthocyanidin found in red-kerneled rice. Red-kerneled rice proanthocyanidin exhibited potent mixed noncompetitive inhibition of human and rat 5-lipoxygenases, with an IC50 values of 15.1 µM against human enzyme, and 7.0 µM against rat enzyme, respectively. This compound decreased leukotriene B4 production in rat basophilic leukemia-2H3 cells. In imiquimod-induced psoriasis-like mouse skin, topical application of the proanthocyanidin suppressed hyperplasia, decreased inflammatory cell infiltration, and down-regulated expression of the psoriasis-associated genes Il17a, Il22, S100a9, and Krt1. Lipid metabolome analysis by electrospray ionization mass spectrometry showed that red-kerneled rice proanthocyanidin treatment of psoriasis-like mouse skin dose-dependently decreased the production of leukotriene B4 but no other arachidonate metabolites. Red-kerneled rice proanthocyanidin inhibits 5-lipoxygenase, resulting in a decrease in leukotriene B4 production and psoriasis-like mouse skin inflammation. These results suggest that this proanthocyanidin may be therapeutically effective for treating leukotriene-related diseases.

MicroRNA-193b-3p alleviates focal cerebral ischemia and reperfusion-induced injury in rats by inhibiting 5-lipoxygenase expression.

AIMS: Ischemic stroke has become one of the main causes of death worldwide. MicroRNAs (miRNAs) have been implicated in cerebral ischemia-reperfusion (I/R) injury and could serve as therapeutic targets. 5-Lipoxygenase (5-LOX) is a key enzyme in the biosynthesis of leukotrienes and has been implicated in inflammatory central nerve system disorders. The objective of this study was to explore the neuroprotective effects of miR-193b-3p against focal cerebral I/R injury in rats by regulating 5-LOX expression. METHODS AND MATERIALS: Adult male Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion and reperfusion injury. The level of miR-193b-3p expression was observed in the rat cortical peri-infarct region after focal cerebral I/R injury. Bioinformatics analysis was used to predict the binding sites of miR-193b-3p, and a dual-luciferase reporter gene assay was applied to verify the potential interaction between 5-LOX mRNA and miR-193b-3p. Then, rats were injected with a miR-193b-3p agomir (modified and enhanced mimic) or antagomir (modified and enhanced inhibitor) in the right lateral ventricle of the brain. Neurological deficit scores, infarct volumes, neuron damage and 5-LOX enzymatic activity and expression were measured. In an in vitro experiment, cultured PC12 cells were exposed to oxygen-glucose deprivation and reperfusion (OGD/R). OGD/R-induced cells were treated with a miR-193b-3p mimic or inhibitor and 5-LOX siRNA. Cell viability, lactate dehydrogenase release, apoptosis rate and 5-LOX expression were evaluated. RESULTS: The level of miR-193b-3p expression was increased in the cortical peri-infarct region of rats with cerebral focal I/R injury. The results of the dual-luciferase reporter gene assay showed that a miR-193b-3p binding site was located in the 3' untranslated region (3'UTR) of 5-LOX mRNA. Neurological deficit scores, infarct volumes and neuronal injury were alleviated by miR-193b-3p agomir treatment but aggravated by miR-193b-3p antagomir. Furthermore, leukotriene B4, cysteinyl-leukotrienes and 5-LOX expression in the cortical peri-infarct region of rats with focal cerebral I/R injury were also downregulated by miR-193b-3p agomir treatment but upregulated by miR-193b-3p antagomir. In PC12 cells, miR-193b-3p mimic significantly decreased OGD/R-induced cell death and reduced lactate dehydrogenase release and 5-LOX expression. In contrast, miR-193b-3p inhibitor exacerbated OGD/R-induced injury in PC12 cells. Additionally, the in vitro effects of miR-193b-3p inhibitor on OGD/R-induced cell injury were partially reversed by 5-LOX siRNA treatment. CONCLUSION: MiR-193b-3p has a potentially neuroprotective effect on focal cerebral I/R-induced injury by inhibiting 5-LOX expression.

Further insight into the dual COX-2 and 15-LOX anti-inflammatory activity of 1,3,4-thiadiazole-thiazolidinone hybrids: The contribution of the substituents at 5th positions is size dependent.

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.

Effect of 5-lipoxygenase inhibitor, VIA-2291 (Atreleuton), on epicardial fat volume in patients with recent acute coronary syndrome.

BACKGROUND AND AIMS: The association between inflammation and atherosclerosis has been well described in the literature. There is now mounting evidence in support of adipose tissue as a reservoir for inflammatory markers. Epicardial adipose tissue (EAT) has been shown to associate with coronary atherosclerosis and found to be a predictor of future adverse cardiovascular events. This study, VIA-EAT, assesses the change in epicardial fat volume (EFV) after treatment with an investigational anti-inflammatory agent (VIA-2291) in a cohort of post-acute coronary syndrome (ACS) patients. METHODS: This study is derived from a post-hoc analysis of a previously conducted randomized clinical trial (NCT00358826). Patients were recruited for a prospective, double-blind, multi-center randomized trial of a 5-lipooxygenase inhibitor or placebo in a 3:1 randomization, including doses of placebo, and 25 mg, 50 mg and 100 mg of active treatment. Cardiac computed tomography was performed at baseline and at 24 weeks after treatment with VIA-2291. EAT and pericardial adipose tissue (PAT) were measured using previously published methodology. A Pearson correlation test was used to determine the relationship between change in epicardial fat and change in plaque composition. RESULTS: We analyzed 54 pre- and post-treatment scans. There were no major differences between traditional cardiovascular risk factors among the 4 randomized study arms. There was a significant decrease in EAT and PAT in patients in the treatment arms vs. placebo, -3.0 ± 8.2mm3 and -3.9 ± 10.9mm3 vs. 1.7 ± 7.5mm3 and 1.4 ± 10.7mm3 (p = 0.001), respectively. The changes in EAT and PAT were more pronounced in patients taking 100 mg of the drug vs. placebo: 4.2 ± 9.6mm3, -7.6 ± 8.5mm3, p = 0.0001, respectively. In a subgroup analysis, reduction in epicardial fat volume correlated with reduction in total atherosclerotic plaque volume across all VIA treatment groups, r = 0.52 (p = 0.004). CONCLUSIONS: After adjustment for traditional cardiovascular risk factors including age, gender, body mass index, dyslipidemia and smoking, VIA-2291 decreases EAT and PAT in individuals with recent ACS. Treatment with the drug also appears to alter plaque volume and composition.