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.

Molecular hybrids of substituted phenylcarbamoylpiperidine and 1,2,4-triazole methylacetamide as potent 15-LOX inhibitors: Design, synthesis, DFT calculations and molecular docking studies.

Inflammation is a multifaceted phenomenon triggered by potentially active mediators acutely released arachidonic acid metabolites partially in lipoxygenase (LOX) pathway which are primarily accountable for causing several diseases in humans. It is widely believed that an inhibitor of the LOX pathway represents a rational approach for designing more potent antiinflammatory leads with druggable super safety profiles. In our continual efforts in search for anti-LOX molecules, the present work was to design a new series of N-alkyl/aralkyl/aryl derivatives (7a-o) of 4-phenyl-5-(1-phenylcarbamoylpiperidine)-4H-1,2,4-triazole-3-thiol which was commenced in seriate formation of phenylcarbamoyl derivative (1), hydrazide (2), semicarbazide (3) and 4-phenyl-5-(1-phenylcarbamoylpiperidine)-4H-1,2,4-triazole-3-thiol (4). The aimed compounds were obtained by reacting 4-phenyl-5-(1-phenylcarbamoylpiperidine)-4H-1,2,4-triazole-3-thiol with assorted N-alkyl/aralkyl/aryl electrophiles. All compounds were characterized by FTIR, 1H-, 13C-NMR spectroscopy, EI-MS and HR-EI-MS spectrometry and screened against soybean 15-LOX for their inhibitory potential using chemiluminescence method. All the compounds except 7m and 7h inhibited the said enzyme remarkably. Compounds 7c,7l, 7j and 7a displayed potent inhibitions ranging from IC50 1.92 ± 0.13 µM to 7.65 ± 0.12 µM. Other analogues 7g, 7o, 7e, 7b, 7d, 7k and 7n revealed excellent inhibitory values ranging from IC50 12.45 ± 0.38 µM to 24.81 ± 0.47 µM. All these compounds did not reveal DPPH radical scavenging activity. Compounds 7i-o maintained > 90 % human blood mononuclear cells (MNCs) viability at 0.125 mM as assayed by MTT whilst others were found toxic. Pharmacokinetic profiles predicted good oral bioavailability and drug-likeness properties of the active scaffolds. SAR investigations showed that phenyl substituted analogue on amide side decreased inhibitory activity due to inductive and mesomeric effects while the mono-alkyl substituted analogues were more active than disubstituted ones and ortho substituted analogues were more potent than meta substituted ones. MD simulation predicted the stability of the 7c ligand and receptor complex as shown by their relative RMSD (root mean square deviation) values. Molecular docking studies displayed hydrogen bonding between the compounds and the enzyme with Arg378 which was common in 7n, 7g, 7h and baicalein. In 7a and quercetin, hydrogen bonding was established through Asn375. RMSD values exhibited good inhibitory profiles in the order quercetin (0.73 Å) < 7 g < baicalein < 7a < 7n < 7 h (1.81 Å) and the binding free energies followed similar pattern. Density functional theory (DFT) data established good correlation between the active compounds and significant activity was associated with more stabilized LUMO (lowest unoccupied molecular orbitals) orbitals. Nevertheless, the present studies declare active analogues like 7c, 7 l, 7a, 7j as leads. Work is ongoing in derivatizing active molecules to explore more effective leads as 15-LOX inhibitors as antiinflammatory agents.

Lipid peroxidation-induced ferroptosis as a therapeutic target for mitigating neuronal injury and inflammation in sepsis-associated encephalopathy: insights into the hippocampal PEBP-1/15-LOX/GPX4 pathway.

BACKGROUND: Sepsis-associated encephalopathy (SAE) refers to the widespread impairment of brain function caused by noncentral nervous system infection mediated by sepsis. Lipid peroxidation-induced ferroptosis contributes to the occurrence and course of SAE. This study aimed to investigate the relationship between neuronal injury and lipid peroxidation-induced ferroptosis in SAE. METHODS: Baseline data were collected from pediatric patients upon admission, and the expression levels of various markers related to lipid peroxidation and ferroptosis were monitored in the serum and peripheral blood mononuclear cells (PBMCs) of patients with SAE as well as SAE model mice. The hippocampal phosphatidylethanolamine-binding protein (PEBP)-1/15-lysine oxidase (LOX)/ glutathione peroxidase 4 (GPX4) pathway was assessed for its role on the inhibitory effect of ferroptosis in SAE treatment. RESULTS: The results showed elevated levels of S100 calcium-binding protein beta (S-100ß), glial fibrillary acidic protein, and malondialdehyde in the serum of SAE patients, while superoxide dismutase levels were reduced. Furthermore, analysis of PBMCs revealed increased transcription levels of PEBP1, LOX, and long-chain fatty acyl-CoA synthetase family member 4 (ACSL4) in SAE patients, while the transcription levels of GPX4 and cystine/glutamate transporter xCT (SLC7A11) were decreased. In comparison to the control group, the SAE mice exhibited increased expression of S-100ß and neuron-specific enolase (NSE) in the hippocampus, whereas the expression of S-100ß and NSE were reduced in deferoxamine (DFO) mice. Additionally, iron accumulation was observed in the hippocampus of SAE mice, while the iron ion levels were reduced in the DFO mice. Inhibition of ferroptosis alleviated the mitochondrial damage (as assessed by transmission electron microscopy, hippocampal mitochondrial ATP detection, and the JC-1 polymer-to-monomer ratio in the hippocampus) and the oxidative stress response induced by SAE as well as attenuated neuroinflammatory reactions. Further investigations revealed that the mechanism underlying the inhibitory effect of ferroptosis in SAE treatment is associated with the hippocampal PEBP-1/15-LOX/GPX4 pathway. CONCLUSION: These results offer potential therapeutic targets for the management of neuronal injury in SAE and valuable insights into the potential mechanisms of ferroptosis in neurological disorders.

Dual COX-2 and 15-LOX inhibition study of novel 4-arylidine-2-mercapto-1-phenyl-1H-imidazolidin-5(4H)-ones: Design, synthesis, docking, and anti-inflammatory activity.

Novel arylidene-5(4H)-imidazolone derivatives 4a-r were designed and evaluated as multidrug-directed ligands, that is, inflammatory, proinflammatory mediators, and reactive oxygen species (ROS) inhibitors. All of the tested compounds showed cyclooxygenase (COX)-1 inhibitory effect more than celecoxib and less than indomethacin and also demonstrated an improved inhibitory activity against 15-lipoxygenase (15-LOX). Compounds 4f, 4l, and 4p exhibited COX-2 selectivity comparable to that of celecoxib, while 4k was the most selective COX-2 inhibitor. Interestingly, the screened results showed that compound 4k exhibited a superior inhibition effect against 15-LOX and was found to be the most selective COX-2 inhibitor over celecoxib, whereas compound 4f showed promising COX-2 and 15-LOX inhibitory activities besides its inhibitory effect against ROS production and its lowering effect of both tumor necrosis factor-α and interleukin-6 levels by ∼80%. Moreover, compound 4f attenuated the lipopolysaccharide-mediated increase in NF-κB activation in RAW 264.7 macrophages. The preferred binding affinity of these molecules was confirmed by docking studies. We conclude that arylidene-5(4H)-imidazolone scaffolds provide promising hits for developing new synthons with anti-inflammatory and antioxidant activities.

Epigenetic regulation of 15-lipoxygenase-1 expression in human chondrocytes by promoter methylation.

OBJECTIVE AND DESIGN: 15-Lipoxygenase-1 (15-LOX-1) catalyzes the biosynthesis of many anti-inflammatory and immunomodulatory lipid mediators and was reported to have protective properties in several inflammatory conditions, including osteoarthritis (OA). This study was designed to evaluate the expression of 15-LOX-1 in cartilage from normal donors and patients with OA, and to determine whether it is regulated by DNA methylation. METHODS: Cartilage samples were obtained at autopsy from normal knee joints and from OA-affected joints at the time of total knee joint replacement surgery. The expression of 15-LOX-1 was evaluated using real-time polymerase chain reaction (PCR). The role of DNA methylation in 15-LOX-1 expression was assessed using the DNA methyltransferase inhibitor 5-Aza-2'-desoxycytidine (5-Aza-dC). The effect of CpG methylation on 15-LOX-1 promoter activity was evaluated using a CpG-free luciferase vector. The DNA methylation status of the 15-LOX-1 promoter was determined by pyrosequencing. RESULTS: Expression of 15-LOX-1 was upregulated in OA compared to normal cartilage. Treatment with 5-Aza-dC increased 15-LOX-1 mRNA levels in chondrocytes, and in vitro methylation decreased 15-LOX-1 promoter activity. There was no difference in the methylation status of the 15-LOX-1 gene promoter between normal and OA cartilage. CONCLUSION: The expression level of 15-LOX-1 was elevated in OA cartilage, which may be part of a repair process. The upregulation of 15-LOX-1 in OA cartilage was not associated with the methylation status of its promoter, suggesting that other mechanisms are involved in its upregulation.

Triple targeting of mutant EGFRL858R/T790M, COX-2, and 15-LOX: design and synthesis of novel quinazolinone tethered phenyl urea derivatives for anti-inflammatory and anticancer evaluation.

We designed and synthesised novel quinazolinone tethered phenyl urea derivatives (6a-p) that triple target the double mutant EGFRL858R/T790M, COX-2, and 15-LOX. Compounds (6e, 6d, 6j, 6m, and 6n) not only had low micromolar IC50 inhibitory activities against the three targets, but they also showed good selectivity for COX-2 over COX-1 and for EGFRL858R/T790M over wild-type EGFR. Except for 6e and 6n, all of the tested compounds inhibited the NO production significantly more potently than celecoxib, diclofenac, and indomethacin. Compounds 6i and 6k reduced ROS levels more effectively than celecoxib and diclofenac. In terms of inhibiting TNF-α production, 6o-treated cells showed TNF-α level, which is ∼10 times lower than celecoxib. Furthermore, 6e and 6j had the highest anticancer activity against the breast cancer cell line BT-459 with growth inhibition percentages of 67.14 and 70.07%, respectively. Docking studies confirm their favoured binding affinity. The proposed compounds could be promising multi-targeted leads.

Novel 2-Thiouracil-5-Sulfonamide Derivatives: Design, Synthesis, Molecular Docking, and Biological Evaluation as Antioxidants with 15-LOX Inhibition.

New antioxidant agents are urgently required to combat oxidative stress, which is linked to the emergence of serious diseases. In an effort to discover potent antioxidant agents, a novel series of 2-thiouracil-5-sulfonamides (4-9) were designed and synthesized. In line with this approach, our target new compounds were prepared from methyl ketone derivative 3, which was used as a blocking unit for further synthesis of a novel series of chalcone derivatives 4a-d, thiosemicarbazone derivatives 5a-d, pyridine derivatives 6a-d and 7a-d, bromo acetyl derivative 8, and thiazole derivatives 9a-d. All compounds were evaluated as antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2), lipid peroxidation, and 15-lipoxygenase (15-LOX) inhibition activity. Compounds 5c, 6d, 7d, 9b, 9c, and 9d demonstrated significant RSA in all three techniques in comparison with ascorbic acid and 15-LOX inhibitory effectiveness using quercetin as a standard. Molecular docking of compound 9b endorsed its proper binding at the active site pocket of the human 15-LOX which explains its potent antioxidant activity in comparison with standard ascorbic acid.

The effects of selenium on GPX4-mediated lipid peroxidation and apoptosis in germ cells.

Emerging evidence suggests that selenium plays an essential role in sperm maturation. However, the specific signaling pathway by which selenium exerts effect has not been elucidated. To evaluate the effect of selenium on GPX4-mediated lipid peroxidation and apoptosis in germ cells, selenium deficiency was modeled by culturing GC2-spd cells in serum-free medium. Treatment with 0.5-µM sodium selenite (NaSe) or 5.0-µM selenomethionine (SeMet) significantly improved the proliferation rate and GPX4 protein expression after selenium deficiency. Moreover, NaSe and SeMet decreased the MDA content and lipid peroxidation. When adenovirus was used to knockdown the expression of the GPX4 gene (shRNA-GPX4), the early apoptosis rate of the shRNA-GPX4 cells was significantly higher than that of the EGFP cells. Increased expression of Caspase3 and Bax, as well as MDA content were observed in the shRNA-GPX4 cells compared with EGFP cells. In further, overexpression of the GPX4 gene (ORF-GPX4) cells exhibited increased cell proliferation and decreased MDA content. However, there was no significant difference in 12/15-lox expression both in ORF-GPX4 cells and shRNA-GPX4 cells. Conclusively, GPX4 was involved in the regulation of lipid peroxidation and apoptosis in GC2-spd cells. Selenium played a role in promoting cell proliferation by mediating GPX4. The regulation of GPX4 may occur independently of 12/15-Lox. These findings confirmed the effect of selenium on spermatogenesis and offered a potential target for treating abnormal semen quality in men.

Exploring ibuprofen derivatives as α-glucosidase and lipoxygenase inhibitors: Cytotoxicity and in silico studies.

This study reports the synthesis of a series of ibuprofen derivatives, including thiosemicarbazides 4a-f, 1,3,4-oxadiazoles 5a-f, 1,3,4-thiadiazoles 6a-f, 1,2,4-triazoles 7a-f, and their S-alkylated derivatives 8a-d. All of the newly synthesized derivatives were analyzed using 1 H NMR, 13 C NMR spectroscopy, and high-resolution mass spectra (electron ionization) spectrometry. These synthetic molecules were examined for their in vitro baking yeast α-glucosidase and soybean 15-lipoxygenase (15-LOX) inhibition and cell viability studies. The results revealed that the compounds N-(3,4-dichlorophenyl)-5-[1-(4-isobutylphenyl)ethyl]-1,3,4-oxadiazol-2-amine 5f (IC50 3.05 ± 1.23 µM) and N-(3-fluorophenyl)-5-[1-(4-isobutylphenyl)ethyl]-1,3,4-oxadiazol-2-amine 5b (IC50 3.12 ± 1.21 µM) were the most potent with respect to the α-glucosidase enzyme while in case of 15-LOX, the compound 4-(2,4-dichlorophenyl)-1-[2-(4-isobutylphenyl)propanoyl]thiosemicarbazide 4e showed potent inhibition with an IC50 value of 55.41 ± 0.41 µM. All these compounds were found least toxic by displaying a blood mononuclear cell viability value of 69.2%-97.8% by the MTT assay compared to the standards when assayed at 0.25 mM concentration. Molecular docking analyses were conducted to evaluate the inhibition profiles of these derivatives against the said enzymes and the data supported the in vitro profiles.

Discovery of natural 15-LOX small molecule inhibitors from Chinese herbal medicine using virtual Screening, biological evaluation and molecular dynamics studies.

Chinese herbal medicines (CHM) are frequently used to treat different types of inflammatory diseases and 15-Lipoxygenase (15-LOX) is a critical target enzyme for treating various inflammatory diseases. In this study, natural 15-LOX inhibitors were identified in CHM using an approach of virtual screening combined with the biological assays. First, an in-house Chinese medicine database containing 360 compounds was screened using a virtual screening approach based on pharmacophore and molecular docking to uncover several novel potential 15-LOX inhibitors. Secondly, the inhibitory effect of virtual screening hits against the 15-LOX enzyme was validated in an in vitro enzyme inhibition assay. Then, a tumor necrosis factor-α (TNF-α) release assay was carried out to explore the anti-inflammatory response of the active compounds. Furthermore, molecular dynamics (MD) simulation and binding free energy calculation were applied to analyze the process of inhibitors binding and also compared the mode of binding of the inhibitors by using the Molecular Mechanics-Generalized Born Surface Area (MM/GBSA) method. Finally, licochalcone B and eriodictyol were confirmed as inhibitors of the 15-LOX enzyme with IC50 values of 9.67 and 18.99 µM, respectively. In vitro cell-based assay showed that licochalcone B and eriodictyol inhibited the release of TNF-α factor in RAW264.7 cells stimulated by lipopolysaccharides (LPS) in a dose-dependent manner. Molecular dynamics and binding free energy analysis showed that the two 15-LOX-ligand systems immediately attained equilibrium with almost 1 Å fluctuation, the calculated binding free energies were found around -18.89 and -12.96 kcal/mol for licochalcone B and eriodictyol, respectively. Thr412, Arg415, Val420, Thr429, Ile602 and Trp606 were the main amino acid residues for the inhibition of 15-LOX enzyme activity. The current study confirms that licochalcone B and eriodictyol are 15-LOX inhibitors and can suppress the release of the TNF-α factor in RAW264.7 cells stimulated by LPS, thus providing a basis for the follow-up research and development for 15-LOX inhibitors.

Utility of novel 2-furanones in synthesis of other heterocyclic compounds having anti-inflammatory activity with dual COX2/LOX inhibition.

Inflammation is associated with the development of several diseases comprising cancer and cardiovascular disease. Agents that suppress cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, besides chemokines have been suggested to minimise inflammation. Here, a variety of novel heterocyclic and non-heterocyclic compounds were prepared from novel three furanone derivatives. The structures of all synthesised compounds were confirmed by elemental and spectral analysis including mass, IR, and 1H-NMR spectroscopy. Anti-inflammatory activities of these synthesised compounds were examined in vitro against COX enzymes, 15-LOX, and tumour necrosis factor-α (TNF-α), using inhibition screening assays. The majority of these derivatives showed significant to high activities, with three pyridazinone derivatives (5b, 8b, and 8c) being the most promising anti-inflammatory agents with dual COX-2/15-LOX inhibition activities along with high TNF-α inhibition activity.

15-LOX-1 has diverse roles in the resensitization of resistant cancer cell lines to doxorubicin.

Lipoxygenases (LOXs) are a family of enzymes that can oxygenate polyunsaturated fatty acids. As a member of the family, 15-lipoxygenase-1 (15-LOX-1) specifically metabolizes arachidonic acid and linoleic acid. 15-LOX-1 can affect physiological and pathophysiological events via regulation of the protein-lipid interactome, alterations in intracellular redox state and production of lipid metabolites that are involved in the induction and resolution of inflammation. Although several studies have shown that 15-LOX-1 has an antitumorigenic role in many different cancer models, including breast cancer, the role of the protein in cancer drug resistance has not been established yet. In this study, we, for the first time, aimed to show the potential role of 15-LOX-1 in acquired doxorubicin (DOX) resistance in MCF7 and HeLa cancer cell lines. Our results show that ALOX15 was transcriptionally downregulated in DOX-resistant cells compared with their drug-sensitive counterparts. Moreover, overexpression of ALOX15 in the drug-resistant cells resulted in resensitization of those cells to DOX in a cell-dependent manner. 15-LOX-1 expression could induce apoptosis by activating PPARγ and enhance the accumulation of DOX in drug-resistant MCF7 cells by altering cellular motility properties, and membrane dynamics. However, HeLa DOX cells did not show any of these effects but were susceptible to cell death when treated with 13(S)-HODE. These results underline the role and importance of 15-LOX-1 in cancer drug resistance, and points to novel mechanisms as a therapeutic approach to overcome cancer drug resistance.

Novel class of benzimidazole-thiazole hybrids: The privileged scaffolds of potent anti-inflammatory activity with dual inhibition of cyclooxygenase and 15-lipoxygenase enzymes.

The present study includes design and synthesis of new molecular hybrids of 2-methylthiobenzimidazole linked to various anti-inflammatory pharmacophores through 2-aminothiazole linker, to investigate the effect of such molecular variation on cyclooxygenase (COX) and 15-lipoxygenase (15-LOX) enzymes inhibition as well as in vivo anti-inflammatory activity. The chemical structures of new hybrids were confirmed using different spectroscopic tools and elemental analyses. Benzimidazole-thiazole hybrids linked to acetyl moiety 13, phenyl thiosemicarbazone 14, 1,3-thiazolines 15a-c and 4-thiazolidinone 16 exhibited significant COX-2 inhibition (IC50 = 0.045-0.075 µM) with significant COX-2 selectivity indices (SI = 142-294). All hybrids revealed potent 15-LOX inhibitory activity (IC50 = 1.67-6.56 µM). Benzimidazole-thiazole hybrid 15b was the most potent dual COX-2 (IC50 = 0.045 µM, SI = 294) inhibitor approximate to celecoxib (COX-2; IC50 = 0.045 µM, SI = 327), with double inhibitory activity versus 15-LOX enzyme (IC50 = 1.67 µM) relative to quercetin (IC50 = 3.34 µM). Three hybrids (14, 15b &16) were selected for in vivo screening using carrageenan-induced paw edema method. Benzimidazole-thiazole hybrid linked to 4-thiazolidinone 16 showed the maximum edema inhibition at both 3 h and 4 h intervals as well (~119% and 102% relative to indomethacin, respectively). The gastric ulcerogenic effect of benzimidazole-thiazole hybrid 16 was estimated compared with indomethacin showing superior gastrointestinal safety profile. In bases of molecular modeling; all new active hybrids were subjected to docking simulation into active sites of COX-2 and 15-LOX enzymes to study the binding mode of these novel potent dual COX-2/15-LOX inhibitors.

Click chemistry synthesis, biological evaluation and docking study of some novel 2'-hydroxychalcone-triazole hybrids as potent anti-inflammatory agents.

A hybrid pharmacophore approach is used to design and synthesize two novel series of 2'-hydroxychalcone-triazole hybrid molecules 6a-j and 8a-j. These compounds were fully characterized by spectral and elemental analyses. They were evaluated in vitro and in vivo for anti-inflammatory activity. Most of compounds were selective inhibitors for COX-2. Among them, compounds 6d, 6f, 6i, 8c, 8e and 8h demonstrated highly potent dual inhibition of COX-2 (IC50 = 0.037-0.041 µM) and 15-LOX (IC50 = 1.41-1.80 µM). Compounds 6i, 8c and 8h showed 116%, 113% and 109% of the in vivo anti-inflammatory activity of celecoxib. Therefore, compounds 6d, 6f, 6i, 8c, 8e and 8h-j are potent dual inhibitors of COX-2 and 15-LOX. Docking study over COX-2 and 15-LOX active sites ensures the binding affinity and selectivity. These compounds are promising candidates for further development as anti-inflammatory drugs.

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.

Cardioprotection of (±)-sodium 5-bromo-2-(α-hydroxypentyl) benzoate (BZP) on mouse myocardium I/R injury through inhibiting 12/15-LOX-2 activity.

(±)-Sodium5-bromo-2-(α-hydroxypentyl) benzoate (brand name: brozopine, BZP, 1a), derived from L-3-n-butylphthalide (L-NBP), has been reported to protect the brain from stoke and has been approved by CFDA in Phase I-II clinical trials. However, it remains to be investigated whether 1a may exhibit any cardioprotective effect on ischemia-reperfusion (I/R) injury. In the current study, C57BL/6 and ICR mice were pretreated with 1a, and myocardium I/R were then performed. We found that 1a not only significantly reduced the infarct size and improved cardiac contractile function after acute MI/R in both species, but also protected hearts from chronic MI-related cardiac injury. Mechanically, we found that 1a physically binds to 12/15-LOX-2 using molecular docking. The shRNA-mediated 12/15-LOX-2 knockdown almost completely blocked the protective effect of 1a. Our findings, for the first time, strongly indicate that 1a may serve as a potent and promising cardioprotective agent in treatment of I/R related injury, at least partially through targeting 12/15-LOX-2.

The importance of 15-lipoxygenase inhibitors in cancer treatment.

Cancer-targeted therapy is an expanding and successful approach in treatment of many types of cancers. One of the main categories of targeted therapy is use of small molecule inhibitors. 15-Lipoxygenase (15-LOX) is an enzyme which reacts with polyunsaturated fatty acids and produces metabolites that are implicated in many important human diseases, such as cancer. Considering the role of 15-LOX (mainly 15-LOX-1) in the progression of some cancers, the discovery of 15-LOX inhibitors could potentially lead to development of novel cancer therapeutics and it can be claimed that 15-LOX inhibitors might be suitable as chemotherapy agents in the near future. This article reviews relevant publications on 15-LOX inhibitors with focus on their anticancer activities in vitro and in vivo. Many 15-LOX inhibitors have been reported for which separate studies have shown their anticancer activities. This review paves the way to further explore the mechanism of their antiproliferative effects via 15-LOX inhibition.

Novel aryl carboximidamide and 3-aryl-1,2,4-oxadiazole analogues of naproxen as dual selective COX-2/15-LOX inhibitors: Design, synthesis and docking studies.

A series of novel naproxen analogues containing 3-aryl-1,2,4-oxadiazoles moiety (4b-g) and their reaction intermediates aryl carboximidamides moiety (3b-g) was synthesized and evaluated in vitro as dual COXs/15-LOX inhibitors. Compounds 3b-g exhibited superior inhibitory activity than celecoxib as COX-2 inhibitors. Compounds 3b-d and 3g were the most potent COX-2 inhibitors with IC50 range of 6.4 - 8.13 nM and higher selectivity indexes (3b, SI = 26.19; 3c, SI = 13.73; 3d, SI = 29.27; 3g, SI = 18.00) comparing to celecoxib (IC50 = 42.60 nM, SI = 8.05). Regarding 15-LOX inhibitory activity, compounds belonging to aryl carboximidamide backbone 3b-e and 3g were the most potent with IC50 range of 1.77-4.91 nM comparing to meclofenamate sodium (IC50 = 5.64 µM). Data revealed that The levels of NO released by aryl carboximidamides 3b-g were more higher than 3-aryl-1,2,4-oxadiazole derivatives 4b-g, which correlated well with their COX-2 inhibitory activities.

Deletion of 12/15-lipoxygenase accelerates the development of aging-associated and instability-induced osteoarthritis.

OBJECTIVE: 12/15-Lipoxygenase (12/15-LOX) catalyzes the generation of various anti-inflammatory lipid mediators, and has been implicated in several inflammatory and degenerative diseases. However, there is currently no evidence that 12/15-LOX has a role in osteoarthritis (OA). The aim of this study was to investigate the role of 12/15-LOX in the pathogenesis of OA. METHODS: The development of aging-associated and destabilization of the medial meniscus (DMM)-induced OA were compared in 12/15-LOX-deficient (12/15-LOX-/-) and wild-type (WT) mice. The extent of cartilage damage was evaluated by histology. The expression of OA markers was evaluated by immunohistochemistry and RT-PCR. Cartilage explants were stimulated with IL-1α in the absence or presence of the 12/15-LOX metabolites, 15-hydroxyeicosatetraenoic acids (15-HETE), 13-hydroxyoctadecadienoic acid (13-HODE) or lipoxin A4 (LXA4), and the levels of matrix metalloproteinases-13 (MMP-13), Nitric oxide (NO) and prostaglandin E2 (PGE2) were determined. The effect of LXA4 on the progression of OA was evaluated in wild type (WT) mice. RESULTS: The expression of 12/15-LOX in cartilage increased during the progression of DMM-induced OA and with aging in WT mice. Cartilage degeneration was more severe in 12/15-LOX-/- mice compared to WT mice in both models of OA, and this was associated with increased expression of MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs, aggrecanases (ADAMTS5), inducible NO synthases (iNOS), and mPGES-1. Treatment of cartilage explants with 12/15-LOX metabolites, suppressed IL-1α-induced production of MMP-13, NO and PGE2, with LXA4 being the most potent. Intra-peritoneal injection of LXA4 reduced the severity of DMM-induced cartilage degradation. CONCLUSIONS: These data suggest an important role of 12/15-LOX in the pathogenesis of OA. They also suggest that activation of this pathway may provide a novel strategy for prevention and treatment of OA.

Human umbilical cord mesenchymal stem cells alleviate inflammatory bowel disease through the regulation of 15-LOX-1 in macrophages.

OBJECTIVE: To investigate the role of human umbilical cord mesenchymal stem cells (hucMSCs) in the treatment of dextran sulfate sodium (DSS)-induced inflammatory bowel disease (IBD). RESULTS: ICG-hucMSCs homed to colon tissues of IBD mice 12 h after injection. The injection of hucMSCs significantly relieved the IBD symptoms and inflammatory cell infiltration. The expression of IL-10 gene increased while those of 15-LOX-1, TNF-α, IL-6, IL-1ß, and IP-10 genes decreased in colon tissues and spleens of hucMSCs-treated mice. The activation of STAT3 was inhibited in colon tissues and spleens of IBD mice that were treated with hucMSCs. In addition, the percentage of macrophages decreased in colon tissues and spleens of hucMSCs-treated IBD mice. Moreover, we provided evidence that in vitro co-culture with hucMSCs inhibited the expression of 15-LOX-1, IL-6 and p-STAT3 in mouse enterocoelia macrophages. CONCLUSIONS: HucMSCs alleviate DSS-induced IBD through the modulation of 15-LOX-1 in macrophages.