Optimization of benzoquinone and hydroquinone derivatives as potent inhibitors of human 5-lipoxygenase

Regulation of mitochondrial function by hydroquinone derivatives as prevention of platelet activation

Platelet activation plays an essential role in the pathogenesis of thrombotic events in different diseases (e.g., cancer, type 2 diabetes, Alzheimer's, and cardiovascular diseases, and even in patients diagnosed with coronavirus disease 2019). Therefore, antiplatelet therapy is essential to reduce thrombus formation. However, the utility of current antiplatelet drugs is limited. Therefore, identifying novel antiplatelet compounds is very important in developing new drugs. In this context, the involvement of mitochondrial function as an efficient energy source required for platelet activation is currently accepted; however, its contribution as an antiplatelet target still has little been exploited. Regarding this, the intramolecular hydrogen bonding of hydroquinone derivatives has been described as a structural motif that allows the reach of small molecules at mitochondria, which can exert antiplatelet activity, among others. In this review, we describe the role of mitochondrial function in platelet activation and how hydroquinone derivatives exert antiplatelet activity through mitochondrial regulation.

Evaluating the inhibitory activity of ferrocenyl Schiff bases derivatives on 5-lipoxygenase: Computational and biological studies

In the search for new 5-LOX inhibitors, two ferrocenyl Schiff base complexes functionalized with catechol ((ƞ5-(E)-C5H4-NCH-3,4-benzodiol)Fe(ƞ5-C5H5) (3a)) and vanillin ((ƞ5-(E)-C5H4-NCH-3-methoxy-4-phenol)Fe(ƞ5-C5H5) (3b)) were obtained. Complexes 3a and 3b were biologically evaluated as 5-LOX inhibitors showed potent inhibition compared to their organic analogs (2a and 2b) and known commercial inhibitors, with IC50 = 0.17 ± 0.05 μM for (3a) and 0.73 ± 0.06 μM for (3b) demonstrated a highly inhibitory and potent effect against 5-LOX due to the incorporation of the ferrocenyl fragment. Molecular dynamic studies showed a preferential orientation of the ferrocenyl fragment toward the non-heme iron of 5-LOX, which, together with electrochemical and in-vitro studies, allowed us to propose a competitive redox deactivation mechanism mediated by water, where Fe(III)-enzyme can be reduced by the ferrocenyl fragment. An Epa/IC50 relationship was observed, and the stability of the Schiff bases was evaluated by SWV in the biological medium, observing that the hydrolysis does not affect the high potency of the complexes, making them interesting alternatives for pharmacological applications.

Nanomedicine-mediated therapeutic approaches for pulmonary arterial hypertension

Nanomedicine has emerged as a field in which there are opportunities to improve the diagnosis, treatment and prevention of incurable diseases. Pulmonary arterial hypertension (PAH) is known as a severe and fatal disease affecting children and adults. Conventional treatments have not produced optimal effectiveness in treating this condition. Several reasons for this include drug instability, poor solubility of the drug and a shortened duration of pharmacological action. The present review focuses on new approaches for delivering anti-PAH drugs using nanotechnology with the aim of overcoming these shortcomings and increasing their efficacy. Solid-lipid nanoparticles, liposomes, metal-organic frameworks and polymeric nanoparticles have demonstrated advantages for the potential treatment of PAH, including increased drug bioavailability, drug solubility and accumulation in the lungs.

Treatment of allergy: Overview of synthetic anti-allergy small molecules in medicinal chemistry

The prevalence of allergic diseases has been continuously increasing over the past few decades, affecting approximately 20-30% of the global population. Allergic reactions to infection of respiratory tract, digestive tract, and skin system involve multiple different targets. The main difficulty of anti-allergy research is how to develop drugs with good curative effect and less side effects by adopting new multi-targets and mechanisms according to the clinical characteristics of different allergic populations and different allergens. This review focuses on information concerning potential therapeutic targets as well as the synthetic anti-allergy small molecules with respect to their medicinal chemistry. The structure-activity relationship and the mechanism of compound-target interaction were highlighted with perspective to histamine-1/4 receptor antagonists, leukotriene biosynthesis, Th2 cytokines inhibitors, and calcium channel blockers. We hope that the study of chemical scaffold modification and optimization for different lead compounds summarized in this review not only lays the foundation for improvement of success rate and efficiency of virtual screening of antiallergic drugs, but also can provide valuable reference for the drug design of related promising research such as allergy, inflammation, and cancer.

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.

Design and synthesis of functionalized 4-aryl-Catechol derivatives as new antiinflammtory agents with in vivo efficacy

Oxidative stress and inflammation are two conditions that coexist in many multifactorial diseases and the discovery of antioxidants is an attractive approach that can simultaneously tackle two or more therapeutic targets of the arachidonic acid cascade. We report that the simple structural variations on the 4-aryl-benzene-1,2-diol side-arm of the scaffold significantly influence the selectivity against 5-LOX vs 12- and 15-LOX. Derivatives 4 a-l were evaluated for their antioxidant activity, using the DPPH, and ferric ion reducing antioxidant power (FRAP) methods. Docking simulations proposed concrete binding of the catechol series to 5-LO. Selected active compound 4-(3,4-dihydroxyphenyl)dibenzofuran (4l) was also tested in different in vivo mouse models of inflammation. 4l (0.1 mg/kg; i.p.) impaired (I) bronchoconstriction in ovalbumin-sensitized mice challenged with acetylcholine, (II) exudate formation in carrageenan-induced paw edema, and (III) zymosan-induced leukocyte infiltration in air pouches. These results pave the way for investigating the therapeutic potential of 4-aryl-benzene-1,2-diol, as novel multitarget therapeutic drugs, able to regulate the complex inflammatory cascade mechanisms.

Lipoxygenase Inhibitors as Cancer Chemopreventives: Discovery, Recent Developments and Future Perspectives

BACKGROUND

Leukotrienes (LTs) constitute a bioactive group of Polyunsaturated Fatty Acid (PUFA) metabolites molded by the enzymatic activity of lipoxygenase (LO) and have a pivotal role in inflammation and allergy. Evidence is accumulating both by in vitro cell culture experiments and animal tumor model studies in support of the direct involvement of aberrant metabolism of arachidonic acid (ACD) in the development of several types of human cancers such as lung, prostate, pancreatic and colorectal malignancies. Several independent experimental data suggest a correlation between tumoral cells viability and LO gene expression, especially, 5-lipoxygenase (5-LO). Overexpressed 5-LO cells live longer, proliferate faster, invade more effectively through extracellular matrix destruction and activate the anti-apoptotic signaling mechanisms more intensively compared to the normal counterparts. Thus, some groups of lipoxygenase inhibitors may be effective as promising chemopreventive agents.

METHODS

A structured search of bibliographic databases for peer-reviewed research literature regarding the role of LO in the pathogenesis of cancer was performed. The characteristics of screened papers were summarized and the latest advances focused on the discovery of new LO inhibitors as anticancer agents were discussed.

RESULTS

More than 180 papers were included and summarized in this review; the majority was about the newly designed and synthesized 5-LO inhibitors as anti-inflammatory and anticancer agents. The enzyme's structure, 5-LO pathway, 5-LO inhibitors structure-activity relationships as well as the correlation between these drugs and a number of most prevalent human cancers were described. In most cases, it has been emphasized that dual cyclooxygenase-2/5-lipoxygenase (COX-2/5-LO) or dual 5-lipoxygenase/microsomal prostaglandin E synthase-1 (5-LO/mPGES-1) inhibitors possess considerable inhibitory activities against their target enzymes as well as potent antiproliferative effects. Several papers disclosing 5-lipoxygenase activating protein (FLAP) antagonists as a new group of 5-LO activity regulators are also subject to this review. Also, the potential of 12-lipoxygenase (12- LO) and 15-lipoxygenase (15-LO) inhibitors as chemopreventive agents was outlined to expand the scope of new anticancer agents discovery. Some peptides and peptidomimetics with anti-LT activities were described as well. In addition, the cytotoxic effects of lipoxygenase inhibitors and their adverse effects were discussed and some novel series of natural-product-derived inhibitors of LO was also discussed in this review.

CONCLUSION

This review gives insights into the novel lipoxygenase inhibitors with anticancer activity as well as the different molecular pharmacological strategies to inhibit the enzyme effectively. The findings confirm that certain groups of LO inhibitors could act as promising chemopreventive agents.

PSB 603 - a known selective adenosine A2B receptor antagonist - has anti-inflammatory activity in mice

A_2B adenosine receptors are present in a wide spectrum of tissues, especially on cells of the immune system. Since these particular receptors have the lowest, of all adenosine receptor subtypes, affinity for adenosine they are believed to play a special role in immunological processes associated with elevated adenosine levels such as inflammation. The aim of this preliminary study was to determine the potential anti-inflammatory properties of compound PSB-603, a potent and selective adenosine A_2B receptor antagonist, in two different experimental models of local and systemic inflammation. In a model of inflammation induced by local carrageenan administration paw edema was measured using a pletysmometer. Additionally, levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and reactive oxygen species (ROS) were determined in the inflamed paw. Using the mouse model of peripheral inflammation induced by intraperitoneal (ip) administration of zymosan A, the influence of the A_2B antagonist on the infiltration of neutrophils into the peritoneum and its effect on the plasma levels of CRP, TNF-α, and IL-6 were investigated. The results showed that PSB-603 administered at a dose of 5 mg/kg b.w. ip significantly reduced inflammation in both tested models. Particularly, it significantly decreased levels of the inflammatory cytokines IL-6, TNF-α and of ROS in the inflamed paw and reduced inflammation of the peritoneum by significantly decreasing the infiltration of leukocytes. Additionally, in the latter model, no statistically significant difference was observed in the CRP level between the control group without inflammation and the group which has been treated with the PSB-603 compound. Thus, the results may indicate the anti-inflammatory activity of adenosine A_2B receptor antagonists in two different models of inflammation.

Synthesis, inhibitory activity and in silico docking of dual COX/5-LOX inhibitors with quinone and resorcinol core

Based on the significant anti-inflammatory activity of natural quinone primin (5a), series of 1,4-benzoquinones, hydroquinones, and related resorcinols were designed, synthesized, characterized and tested for their ability to inhibit the activity of cyclooxygenase (COX-1 and COX-2) and 5-lipoxygenase (5-LOX) enzymes. Structural modifications resulted in the identification of two compounds 5b (2-methoxy-6-undecyl-1,4-benzoquinone) and 6b (2-methoxy-6-undecyl-1,4-hydroquinone) as potent dual COX/5-LOX inhibitors. The IC50 values evaluated in vitro using enzymatic assay were for compound 5b IC50 = 1.07, 0.57, and 0.34 μM and for compound 6b IC50 = 1.07, 0.55, and 0.28 μM for COX-1, COX-2, and 5-LOX enzyme, respectively. In addition, compound 6d was identified as the most potent 5-LOX inhibitor (IC50 = 0.14 μM; reference inhibitor zileuton IC50 = 0.66 μM) from the tested compounds while its inhibitory potential against COX enzymes (IC50 = 2.65 and 2.71 μM for COX-1 and COX-2, respectively) was comparable with the reference inhibitor ibuprofen (IC50 = 4.50 and 2.46 μM, respectively). The most important structural modification leading to increased inhibitory activity towards both COXs and 5-LOX was the elongation of alkyl chain in position 6 from 5 to 11 carbons. Moreover, the monoacetylation in ortho position of bromo-hydroquinone 13 led to the discovery of potent (IC50 = 0.17 μM) 5-LOX inhibitor 17 (2-bromo-6-methoxy-1,4-benzoquinone) while bromination stabilized the hydroquinone form. Docking analysis revealed the interaction of compounds with Tyr355 and Arg120 in the catalytic site of COX enzymes, while the hydrophobic parts of the molecules filled the hydrophobic substrate channel leading up to Tyr385. In the allosteric catalytic site of 5-LOX, compounds bound to Tyr142 and formed aromatic interactions with Arg138. Taken together, we identified optimal alkyl chain length for dual COX/5-LOX inhibition and investigated other structural modifications influencing COX and 5-LOX inhibitory activity.

Study of two isoforms of lipoxygenase by kinetic assays, docking and molecular dynamics of a specialised metabolite isolated from the aerial portion of Lithrea caustica (Anacardiaceae) and its synthetic analogs

Our investigation focused on the characterization and study of epicuticular leaf extracts (dichloromethane extract) and certain derivatives of Lithrea caustica (Molina) Hook and Arn. (Anacardiaceae) as inhibitors of 15 soybean and 5 human lipoxygenases (15-sLOX and 5-hLOX). From the epicuticular extract of leaves, the compound (Z)-3-(pentadec-10'-enyl)-catechol (Litreol) was isolated, and three hemisynthetic derivatives were prepared, as they are 3-pentadecylcatechol, (Z)-1,2-diacetyl-3-(pentadec-10'-enyl)-benzene and 1,2-diacetyl-3-pentadecylbenzene. The inhibitory activities for the four compounds against 15-sLOX and 5-hLOX were determined, being (Z)-3-(pentadec-10'-enyl)-catechol (IC₅₀ 54.77 μM and 2.09 μM, respectively) and 3-pentadecylcatechol (IC₅₀ 55.28 μM and 2.74 μM, respectively), the most interesting compounds assayed. The kinetic studies for (Z)-3-(pentadec-10'-enyl)-catechol and 3-pentadecylcatechol showed a mixed inhibition mechanism to 5-LOX. Finally, docking and molecular dynamics studies were performed to characterize and describe how the chemical structures could be correlated to the decreased 5-hLOX activity observed in the in vitro studies.

Anti-Inflammatory Drugs as Anticancer Agents

Inflammation is strictly associated with cancer and plays a key role in tumor development and progression. Several epidemiological studies have demonstrated that inflammation can predispose to tumors, therefore targeting inflammation and the molecules involved in the inflammatory process could represent a good strategy for cancer prevention and therapy. In the past, several clinical studies have demonstrated that many anti-inflammatory agents, including non-steroidal anti-inflammatory drugs (NSAIDs), are able to interfere with the tumor microenvironment by reducing cell migration and increasing apoptosis and chemo-sensitivity. This review focuses on the link between inflammation and cancer by describing the anti-inflammatory agents used in cancer therapy, and their mechanisms of action, emphasizing the use of novel anti-inflammatory agents with significant anticancer activity.

Formulation and Characterization of Solid Lipid Nanoparticles Loading RF22-c, a Potent and Selective 5-LO Inhibitor, in a Monocrotaline-Induced Model of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a rare but fatal disease characterized by persistent elevated blood pressure in the pulmonary circulation, due to increased resistance to blood flow, through the lungs. Advances in the understanding of the pathobiology of PAH clarify the role of leukotrienes (LTs) that appear to be an exciting new target for disease intervention. Over the years, our group has long investigated this field, detecting the 1,2-benzoquinone RF-22c as the most powerful and selective competitive inhibitor of the enzyme 5-lipoxygenase (5-LO). With the aim to improve the bioavailability of RF-22c and to confirm the role of 5-LO as therapeutic strategy for PAH treatment, we developed a solid lipid nanoparticle (SLN) loaded with drug. Therefore, in monocrotaline (MCT) rat model of PAH, the role of 5-LO has been investigated through the formulation of RF-22c-SLN. The rats were randomly grouped into control group, MCT group, and MCT + RF22-c group. After 21 days, all the animals were sacrificed to perform functional and histological evaluations. RF22-c-SLN treatment was able to significantly reduce the mean pulmonary arterial pressure (mPAP) and precapillary resistance (R-pre) compared to the MCT group. The MCT induced rise in medial wall thickness of pulmonary arterioles, and the cardiomyocytes width were significantly attenuated by RF22-c-SLN formulation upon treatment. The results showed that the selective inhibition of 5-LO improved hemodynamic parameters as well as vascular and cardiac remodeling by preventing induced pulmonary hypertension. The improved sustained release properties and targeting abilities achieved with the innovative nanotechnological approach may be therapeutically beneficial for PAH patients as a consequence of the increase of pharmacological effects and of the possible reduction and/or optimization of the drug frequency of administration.

A Hydroquinone-Based Derivative Elicits Apoptosis and Autophagy via Activating a ROS-Dependent Unfolded Protein Response in Human Glioblastoma

5-Lipoxygenase (5-LO) has been reported to be highly expressed in brain tumors and to promote glioma cell proliferation. Therefore, we investigated the anticancer activity of the novel 5-LO inhibitor derivative 3-tridecyl-4,5-dimethoxybenzene-1,2-diol hydroquinone (EA-100C red) on glioblastoma (GBM) cell growth. Cell viability was evaluated by MTT assay. The effects of the compound on apoptosis, oxidative stress and autophagy were assessed by flow cytometry (FACS). The mode of action was confirmed by Taqman apoptosis array, Real Time qPCR, confocal microscopy analysis and the western blotting technique. Our results showed that EA-100C Red had a higher anti-proliferative effect on LN229 as compared to U87MG cells. The compound induced a significant increase of apoptosis and autophagy and up-regulated pro-apoptotic genes (Bcl3, BNIP3L, and NFKBIA) in both GBM cell lines. In this light, we studied the effects of EA-100C red on the expression of CHOP and XBP1, that are implicated in ER-stress-mediated cell death. In summary, our findings revealed that EA-100C red induced ER stress-mediated apoptosis associated to autophagy in GBM cells through CHOP and Beclin1 up-regulation and activation of caspases 3, 9, JNK and NF-kappaB pathway. On these bases, EA-100C red could represent a promising compound for anti-cancer treatment.

Localization of Ion Concentration Gradients for Logic Operation

Adjustment of the environmental acidity is a powerful method for fine-tuning the outcome of many chemical processes. Numerous strategies have been developed for the modification of pH in bulk as well as locally. Electrochemical and photochemical processes provide a powerful approach for on-demand generation of ion concentration gradients locally at solid-liquid interfaces. Spatially organized in individual way electrodes provide a particular pattern of proton distribution in solution. It opens perspectives to iontronics which is a bioinspired approach to signaling, information processing, and storing by spatial and temporal distribution of ions. We prove here that soft layers allow to control of ion mobility over the surface as well as processes of self-organization are closely related to change in entropy. In this work, we summarize the achievements and discuss perspectives of ion gradients in solution for information processing.

Electrochemical triggering of lipid bilayer lift-off oscillation at the electrode interface

In situ studies of transmembrane channels often require a model bioinspired artificial lipid bilayer (LB) decoupled from its underlaying support. Obtaining free-standing lipid membranes is still a challenge. In this study, we suggest an electrochemical approach for LB separation from its solid support via hydroquinone oxidation. Layer-by-layer deposition of polyethylenimine (PEI) and polystyrene sulfonate (PSS) on the gold electrode was performed to obtain a polymeric nanocushion of [PEI/PSS]3/PEI. The LB was deposited on top of an underlaying polymer support from the dispersion of small unilamellar vesicles due to their electrostatic attraction to the polymer support. Since lipid zwitterions demonstrate pH-dependent charge shifting, the separation distance between the polyelectrolyte support and LB can be adjusted by changing the environmental pH, leading to lipid molecules recharge. The proton generation associated with hydroquinone oxidation was studied using scanning vibrating electrode and scanning ion-selective electrode techniques. Electrochemical impedance spectroscopy is suggested to be a powerful instrument for the in situ observation of processes associated with the LB-solid support interface. Electrochemical spectroscopy highlighted the reversible disappearance of the LB impact on impedance in acidic conditions set by dilute acid addition as well as by electrochemical proton release on the gold electrode due to hydroquinone oxidation.

Design, synthesis and identification of novel coumaperine derivatives for inhibition of human 5-LOX: Antioxidant, pseudoperoxidase and docking studies

5-Lipoxygenase (5-LOX) is a key enzyme involved in the biosynthesis of pro-inflammatory leukotrienes, leading to asthma. Developing potent 5-LOX inhibitors especially, natural product based ones, are highly attractive. Coumaperine, a natural product found in white pepper and its derivatives were herein developed as 5-LOX inhibitors. We have synthesized twenty four derivatives, characterized and evaluated their 5-LOX inhibition potential. Coumaperine derivatives substituted with multiple hydroxy and multiple methoxy groups exhibited best 5-LOX inhibition. CP-209, a catechol type dihydroxyl derivative and CP-262-F2, a vicinal trihydroxyl derivative exhibited, 82.7% and 82.5% inhibition of 5-LOX respectively at 20 µM. Their IC₅₀ values are 2.1 ± 0.2 µM and 2.3 ± 0.2 µM respectively, and are comparable to zileuton, IC₅₀ = 1.4 ± 0.2 µM. CP-155, a methylenedioxy derivative (a natural product) and CP-194, a 2,4,6-trimethoxy derivative showed 76.0% and 77.1% inhibition of 5-LOX respectively at 20 µM. Antioxidant study revealed that CP-209 and 262-F2 (at 20 µM) scavenged DPPH radical by 76.8% and 71.3% respectively. On the other hand, CP-155 and 194 showed very poor DPPH radical scavenging activity. Pseudo peroxidase assay confirmed that the mode of action of CP-209 and 262-F2 were by redox process, similar to zileuton, affecting the oxidation state of the metal ion in the enzyme. On the contrary, CP-155 and 194 probably act through some other mechanism which does not involve the disruption of the oxidation state of the metal in the enzyme. Molecular docking of CP-155 and 194 to the active site of 5-LOX and binding energy calculation suggested that they are non-competitive inhibitors. The In-Silico ADME/TOX analysis shows the active compounds (CP-155, 194, 209 and 262-F2) are with good drug likeliness and reduced toxicity compared to existing drug. These studies indicate that there is a great potential for coumaperine derivatives to be developed as anti-inflammatory drug.

Discovery of a benzenesulfonamide-based dual inhibitor of microsomal prostaglandin E2 synthase-1 and 5-lipoxygenase that favorably modulates lipid mediator biosynthesis in inflammation

Leukotrienes (LTs) and prostaglandin (PG)E2, produced by 5-lipoxygenase (5-LO) and microsomal prostaglandin E2 synthase-1 (mPGES-1), respectively, are key players in inflammation, and pharmacological suppression of these lipid mediators (LM) represents a strategy to intervene with inflammatory disorders. Previous studies revealed that the benzenesulfonamide scaffold displays efficient 5-LO-inhibitory properties. Here, we structurally optimized benzenesulfonamides which led to an N-phenylbenzenesulfonamide derivative (compound 47) with potent inhibitory activities (IC50 = 2.3 and 0.4 μM for isolated 5-LO and 5-LO in intact cells, respectively). Compound 47 prevented the interaction of 5-LO with its activating protein (FLAP) at the nuclear envelope in transfected HEK293 cells as shown by in situ proximity ligation assay. Comprehensive assessment of the LM profile produced by human macrophages revealed the ability of 47 to selectively down-regulate pro-inflammatory LMs (i.e. LTs and PGE2) in M1 but to enhance the formation of pro-resolving LMs (i.e. resolvins and maresins) in M2 macrophages. Moreover, 47 strongly inhibited LT formation and cell infiltration in two in vivo models of acute inflammation (i.e., peritonitis and air pouch sterile inflammation in mice). Together, 47 represents a novel LT biosynthesis inhibitor with an attractive pharmacological profile as anti-inflammatory drug that also promotes the biosynthesis of pro-resolving LM.

Structural insight into the optimization of ethyl 5-hydroxybenzo[g]indol-3-carboxylates and their bioisosteric analogues as 5-LO/m-PGES-1 dual inhibitors able to suppress inflammation

The release of pro-inflammatory mediators, such as prostaglandines (PGs) and leukotrienes (LTs), arising from the arachidonic acid (AA) cascade, play a crucial role in initiating, maintaining, and regulating inflammatory processes. New dual inhibitors of 5-lipoxygenase (5-LO) and microsomal prostaglandin E₂ synthase-1 (mPGES-1), that block, at the same time, the formation of PGE₂ and LTs, are currently emerged as a highly interesting drug candidates for better pharmacotherapie of inflammation-related disorders. Following our previous studies, we here performed a detailed structure-based design of benzo[g]indol-3-carboxylate derivatives, disclosing several new key factors that affect both enzyme activity. Ethyl 2-(3,4-dichlorobenzyl)-5-hydroxy-1H-benzo[g]indole-3-carboxylate (4b, RAF-01) and ethyl 2-(3,4-dichlorophenyl)-5-hydroxy-1H-benzo[g]indole-3-carboxylate (7h, RAF-02) emerged as the most active compounds of the series. Additionally, together with selected structure based analogues, both derivatives displayed significant in vivo anti-inflammatory properties. In conclusion, modeling and experimental studies lead to the discovery of new candidate compounds prone to further developments as multi-target inhibitors of the inflammatory pathway.

Recent advances in the search for novel 5-lipoxygenase inhibitors for the treatment of asthma

The products of 5-lipoxygenase are synthesized and released in the airway when an asthmatic reaction occurs. 5-lipoxygenase via arachidonic acid metabolism produces leukotrienes that mediate bronchoconstriction and inflammatory modifications essential in the pathophysiology of asthma. Until to now, only one approved 5-LO inhibitor, zileuton, can be found as a potential therapy for asthma. With the increasing number of indications for anti-leukotriene (anti-LT) drugs, the development of 5-LO inhibitor agents becomes increasingly important. The present MiniReview reports an update on 5-LO inhibitors currently under clinical investigation. In addition, the latest advances focused on the development of new 5-lipoxygenase inhibitors as asthma anti-inflammatory agents are also discussed.

Recent acquisitions on oxyprenylated secondary metabolites as anti-inflammatory agents

Oxyprenylated secondary metabolites from plants, fungi, and bacteria, and their semisynthetic derivatives have been subject of growing interest during the last decade. Such natural products in fact have been discovered as potentially novel lead compounds for a series of pharmacological activities, mainly in terms of anti-cancer and anti-inflammatory ones. Especially during the last 5 years, a wider panel of prenyloxy secondary metabolites have been investigated from chemical and biological points of view and these include benzoic acids, alcohols, aldehydes, chalcones, anthraquinones, 1,4-naphthoquinones, other than the well known oxyprenylated ferulic acid and coumarin derivatives. The aim of this comprehensive review is to focus on the anti-inflammatory properties and related mechanisms of action of selected classes of oxyprenylated naturally occurring compounds and their semisynthetic analogues covering the literature period from 2011 to 2017. In vitro and in vivo data on their pharmacological activity triggering different pathways of the overall inflammatory machinery as well as structure activity relationship acquisitions will be summarized in order to make a detailed survey of the most recent reports on the potential of the title compounds as a novel class of anti-inflammatory agents.