Discovery of Novel Orally Active Tetrahydro-Naphthyl-N-Acylhydrazones with In Vivo Anti-TNF-α Effect and Remarkable Anti-Inflammatory Properties

Exploring the Conformational Effects of N- and C-Methylation of N-Acylhydrazones

N-Acylhydrazones (NAH) are privileged structures in chemistry and medicinal chemistry. In this study, we describe the conformational effects of N- and C-methylated N-acylhydrazone derivatives, combining theoretical and experimental data analysis. Four N-acylhydrazone (NAH) derivatives (4-7) were synthesized and structurally characterized to investigate the impact of methylation on their conformational preferences and electronic properties. The structural characterization by NMR spectroscopy, including 2D techniques (HSQC, HMBC, and NOESY), confirmed the exclusive formation of (E)-diastereomers. Theoretical conformational analysis using density functional theory (DFT) calculations (CAM-B3LYP/6-31+G(d,p) with the C-PCM solvation model) revealed that N-methylation (6) significantly alters the preferred dihedral angle (O=C-N-X), inducing a shift from an antiperiplanar to a synperiplanar conformation. Notably, compound 7 showed two possible conformers in solution, anti and syn at the amide bond, and exhibited a greater deviation from planarity due to steric effects imposed by the two methyl groups, which disrupt conjugation within the NAH moiety. This was further supported by natural bond orbital (NBO) analysis, which demonstrated changes in electron density distribution, particularly at the carbonyl and imine carbons, correlating well with the calculated and experimental 13C NMR chemical shifts. Noncovalent interaction (NCI) analysis and powder X-ray diffraction provided additional evidence for these conformational trends, reinforcing the influence of methylation on NAH planarity. The findings highlight the steric and electronic consequences of methylation on NAH derivatives, which may have implications for their biological activity and molecular recognition properties.

Synthesis, Antimicrobial - Cytotoxic Evaluation, and Molecular Docking Studies of Quinolin-2-one Hydrazones Containing Nitrophenyl or Isonicotinoyl/Nicotinoyl Moiety

By applying the hybrid molecular strategy, in this study, we reported the synthesis of fifteen quinolin-2-one hydrazones containing nitrophenyl or nicotinonyl/isonicotinoyl moiety, followed by in vitro and in silico evaluations of their potential antimicrobial and anticancer activities. In vitro antimicrobial evaluation of the target compounds on seven pathogenic strains, applying the broth microdilution method, revealed that compound 4a demonstrated the most potential antifungal activity against C. albicans (MIC 512 μg mL-1) and C. krusei (MIC 128 μg mL-1). In vitro cytotoxic evaluation of the target compounds on three human cancer cell lines, employing the MTT method, suggested that compound 5c exhibited the most potential cytotoxicities against HepG2 (IC50 10.19 μM), A549 (IC50 20.43 μM), and MDA-MB-231 (IC50 16.82 μM) cells. Additionally, molecular docking studies were performed to investigate the binding characteristics of compounds 4a and 5c with fungal lanosterol 14α-demethylase and human topoisomerase I-II, respectively, thereby contributing to the elucidation of their in vitro antifungal and cytotoxic properties. Furthermore, compounds 4a and 5c, via SwissADME prediction, could exhibit favorable physicochemical and pharmacokinetic properties. In conclusion, this study provides valuable insights into the potential of quinolin-2-one hydrazones as promising candidates for the development of novel antimicrobial and anticancer agents in the future.

Synthesis and Characterization of New N-acyl Hydrazone Derivatives of Carprofen as Potential Tuberculostatic Agents

N-acyl hydrazone (NAH) is recognized as a promising framework in drug design due to its versatility, straightforward synthesis, and attractive range of biological activities, including antimicrobial, antitumoral, analgesic, and anti-inflammatory properties. In the global context of increasing resistance of pathogenic bacteria to antibiotics, NAHs represent potential solutions for developing improved treatment alternatives. Therefore, this research introduces six novel derivatives of (EZ)-N'-benzylidene-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide, synthesized using a microwave-assisted method. In more detail, we joined two pharmacophore fragments in a single molecule, represented by an NSAID-type carprofen structure and a hydrazone-type structure, obtaining a new series of NSAID-N-acyl hydrazone derivatives that were further characterized spectrally using FT-IR, NMR, and HRMS investigations. Additionally, the substances were assessed for their tuberculostatic activity by examining their impact on four strains of M. tuberculosis, including two susceptible to rifampicin (RIF) and isoniazid (INH), one susceptible to RIF and resistant to INH, and one resistant to both RIF and INH. The results of our research highlight the potential of the prepared compounds in fighting against antibiotic-resistant M. tuberculosis strains.

N-Acylhydrazone Pharmacophore's Analgesic and Anti-inflammatory Profile: Recent Advancements during the Past Ten Years

Due to its important biological and pharmacological properties, in the field of medicinal chemistry and drug discovery, the N-acylhydrazone motif has shown to be extremely adaptable and promising. This scaffold has become a crucial component in the synthesis of numerous bioactive agents. N-Acylhydrazones are also interesting biological and synthetic tools due to their easy and straightforward synthesis. The current review provides a summary of the analgesic and anti-inflammatory activities of N-acylhydrazone derivatives over the past ten years. A brief discussion of structure-activity relationships is also provided which may guide researchers in medicinal chemistry to develop derivatives based on N-acylhydrazone scaffold as potent anti-inflammatory candidates.

Synthesis, Biological, Spectroscopic and Computational Investigations of Novel N-Acylhydrazone Derivatives of Pyrrolo[3,4-d]pyridazinone as Dual COX/LOX Inhibitors

Secure and efficient treatment of diverse pain and inflammatory disorders is continually challenging. Although NSAIDs and other painkillers are well-known and commonly available, they are sometimes insufficient and can cause dangerous adverse effects. As yet reported, derivatives of pyrrolo[3,4-d]pyridazinone are potent COX-2 inhibitors with a COX-2/COX-1 selectivity index better than meloxicam. Considering that N-acylhydrazone (NAH) moiety is a privileged structure occurring in many promising drug candidates, we decided to introduce this pharmacophore into new series of pyrrolo[3,4-d]pyridazinone derivatives. The current paper presents the synthesis and in vitro, spectroscopic, and in silico studies evaluating the biological and physicochemical properties of NAH derivatives of pyrrolo[3,4-d]pyridazinone. Novel compounds 5a-c-7a-c were received with high purity and good yields and did not show cytotoxicity in the MTT assay. Their COX-1, COX-2, and 15-LOX inhibitory activities were estimated using enzymatic tests and molecular docking studies. The title N-acylhydrazones appeared to be promising dual COX/LOX inhibitors. Moreover, spectroscopic and computational methods revealed that new compounds form stable complexes with the most abundant plasma proteins-AAG and HSA, but do not destabilize their secondary structure. Additionally, predicted pharmacokinetic and drug-likeness properties of investigated molecules suggest their potentially good membrane permeability and satisfactory bioavailability.

Molecular Hybridization Strategy on the Design, Synthesis, and Structural Characterization of Ferrocene-N-acyl Hydrazones as Immunomodulatory Agents

Immunomodulatory agents are widely used for the treatment of immune-mediated diseases, but the range of side effects of the available drugs makes necessary the search for new immunomodulatory drugs. Here, we investigated the immunomodulatory activity of new ferrocenyl-N-acyl hydrazones derivatives (SintMed(141−156). The evaluated N-acyl hydrazones did not show cytotoxicity at the tested concentrations, presenting CC50 values greater than 50 µM. In addition, all ferrocenyl-N-acyl hydrazones modulated nitrite production in immortalized macrophages, showing inhibition values between 14.4% and 74.2%. By presenting a better activity profile, the ferrocenyl-N-acyl hydrazones SintMed149 and SintMed150 also had their cytotoxicity and anti-inflammatory effect evaluated in cultures of peritoneal macrophages. The molecules were not cytotoxic at any of the concentrations tested in peritoneal macrophages and were able to significantly reduce (p < 0.05) the production of nitrite, TNF-α, and IL-1β. Interestingly, both molecules significantly reduced the production of IL-2 and IFN-γ in cultured splenocytes activated with concanavalin A. Moreover, SintMed150 did not show signs of acute toxicity in animals treated with 50 or 100 mg/kg. Finally, we observed that ferrocenyl-N-acyl hydrazone SintMed150 at 100 mg/kg reduced the migration of neutrophils (44.6%) in an acute peritonitis model and increased animal survival by 20% in an LPS-induced endotoxic shock model. These findings suggest that such compounds have therapeutic potential to be used to treat diseases of inflammatory origin.

Novel Regioisomeric Analogues of Naphthyl-N-Acylhydrazone Derivatives and Their Anti-Inflammatory Effects

BACKGROUND

When homeostasis is disturbed it can result in a pathological event named inflammation. The main drugs used in the treatment consist of non-steroidal and steroidal anti-inflammatory drugs. However, the side effects remain an obstacle during the treatments. In this study, we aimed to evaluate three new regioisomers analogues of naphthyl-N-acylhydrazone derivatives.

METHODS

Acute models of inflammation in vivo (formalin-induced licking and carrageenan-induced inflammation) as well as in vitro were used to evaluate the effects of LASSBio-2039, LASSBio-2040, and LASSBio-2041.

RESULTS

All three substances (at 1, 10 or 30 µmol/kg) presented significant effects in the in vivo model reducing leukocyte migration, nitric oxide (NO) and interleukin-1β production. It was observed that only LASSBio-2039 significantly reduced cell migration in vitro. None of the LASSBios affected inducible nitric oxide synthase activity nor presented nitric oxide (NO) scavenger effect. No toxic effect was observed, either in vivo or in vitro. The new regioisomers analogues of naphthyl-N-acylhydrazone derivatives presented significant anti-inflammatory activity, suggesting LASSBio-2039 has a direct effect in leukocytes migratory capacity.

CONCLUSIONS

Taken together, the data indicate that these substances present promising effects for the development of a prototype for new drugs.

Quantum Computational Investigation of (E)-1-(4-methoxyphenyl)-5-methyl-N′-(3-phenoxybenzylidene)-1H-1,2,3-triazole-4-carbohydrazide

The title compound was synthesized and structurally characterized. Theoretical IR, NMR (with the GIAO technique), UV, and nonlinear optical properties (NLO) in four different solvents were calculated for the compound. The calculated HOMO–LUMO energies using time-dependent (TD) DFT revealed that charge transfer occurs within the molecule, and probable transitions in the four solvents were identified. The in silico absorption, distribution, metabolism, and excretion (ADME) analysis was performed in order to determine some physicochemical, lipophilicity, water solubility, pharmacokinetics, drug-likeness, and medicinal properties of the molecule. Finally, molecular docking calculation was performed, and the results were evaluated in detail.

Antinociceptive Effects of Aza-Bicyclic Isoxazoline-Acylhydrazone Derivatives in Different Models of Nociception in Mice

BACKGROUND

In a study recently published by our research group, the compounds isoxazoline-acylhydrazone derivatives R-99 and R-123 presented promising antinociceptive activity. However, the mechanism of action of this compound is still unknown.

OBJECTIVE

This study aimed to assess the mechanisms involved in the antinociceptive activity of these compounds in chemical models of pain.

METHODS

Animals were orally pretreated and evaluated in the acetic acid-, formalin-, capsaicin-, carrageenan- and Complete Freund's Adjuvant (CFA)-induced pain models in mice. The effects of the compounds after pretreatment with naloxone, prazosin, yohimbine, atropine, L-arginine, or glibenclamide were studied, using the acetic acid-induced writhing test to verify the possible involvement of opioid, α1-adrenergic, α2-adrenergic or cholinergic receptors, and nitric oxide or potassium channels pathways, respectively.

RESULTS

R-99 and R-123 compounds showed significant antinociceptive activity on pain models induced by acetic acid, formalin, and capsaicin. Both compounds decreased the mechanical hyperalgesia induced by carrageenan or CFA in mice. The antinociceptive effects of R-99 and R-123 on the acetic acid-induced writhing test were significantly attenuated by pretreatment with naloxone, yohimbine or atropine. R-99 also showed an attenuated response after pretreatment with atropine and glibenclamide. However, on the pretreatment with prazosin, there was no change in the animals' response to both compounds.

CONCLUSION

R-99 and R-123 showed antinociceptive effects related to mechanisms that involve, at least in part, interaction with the opioid and adrenergic systems and TRPV1 pathways. The compound R-99 also interacts with the cholinergic pathways and potassium channels.

Characterization of βN-Octadecanoyl-5-hydroxytryptamide Anti-Inflammatory Effect

Background: N-octadecanoyl-5-hydroxytryptamide (C₁₈-5HT) is an amide that can be obtained by the coupling of serotonin and octadecanoic acid. This study aims to characterize the in vivo and in vitro anti-inflammatory activity of C₁₈-5HT. Methods: A subcutaneous air pouch model (SAP) was used. The exudates were collected from SAP after carrageenan injection to assess cell migration and inflammatory mediators production. RAW 264.7 cells were used for in vitro assays. Results: C₁₈-5HT significantly inhibited leukocyte migration into the SAP as well as nitric oxide (NO) and cytokines production and protein extravasation. We also observed an reduction in some cytokines and an increase in IL-10 production. Assays conducted with RAW 264.7 cells indicated that C₁₈-5HT inhibited NO and cytokine produced. Conclusions: Taken together, our data suggest that C₁₈-5HT presents a significant effect in different cell types (leukocytes collected from exudate, mainly polumorphonuclear leukocytes and cell culture macrophages) and is a promising compound for further studies for the development of a new anti-inflammatory drug.

Biocompatibility and mechanical properties evaluation of chitosan films containing an N-acylhydrazonic derivative

The N-acylhydrazone subunit is considered a privileged structure in medicinal chemistry for its importance in pharmaceutical research. Also, alternative methods to deliver these molecules have a great pharmaceutical interest. Therefore, the objective of this work was to encapsulate JR19, an N-acyl hydrazone subunit, into chitosan films and evaluate several properties relevant for transdermal delivery, including biocompatibility using in vitro tests. CHI + JR19 film demonstrates greater strength, flexibility, water absorption capacity, low contact angle and higher surface roughness when compared to CHI. Agar diffusion and 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay show the absence of cytotoxicity and the higher cell viability for CHI + JR19 films. Therefore, the addition of JR19 in the system positively influenced mechanical properties and granted better compatibility with biological environments, showing the potential to treat skin inflammation.

Therapeutic Effects of Anti-Inflammatory N-Acylhydrazones in the Resolution of Experimental Colitis

Inflammatory bowel diseases are caused by inflammation of the gastrointestinal tract, which may or may not have a specific cause or pathogen. They affect millions of people around the world and there are still few effective treatments. The aim of this work is to investigate the anti-inflammatory effect of the IKK-β inhibitor LASSBio-1524 and its three analogs, LASSBio-1760, LASSBio-1763, and LASSBio-1764, on mediator production and expression of inflammatory enzymes using experimental animal models of intestinal inflammatory diseases. Colitis was performed using two different models, which mimic Crohn disease (induced by dinitrobenzene acid) and ulcerative colitis (induced by sodium dextran sulfate) in mice. In both models, a therapeutic protocol with a daily dose of 1, 3, or 30 μmol/kg was performed. LASSBio-1524 and its three analogs reduced the secretion of tumor necrosis factor-α, IL-1β, IL-6, IL-12, and IFN-γ and increased secretion of IL-10, protecting gastrointestinal homeostasis. All compounds reduced macro- and microscopic colonic damage caused by experimental colitis and p38 mitogen-activated protein kinase expression in the colon, as well as leukocytosis and anemia resulting from the disease. Our data may suggest LASSBio-1524 and its analogs (LASSBio-1760, LASSBio-1763, and LASSBio-1764) as promising candidates for new prototypes designed to treat inflammatory bowel diseases. SIGNIFICANCE STATEMENT: Three new N-acylhydrazones were synthetized as analogs of LASSBio-1524. All new substances were evaluated in dextran sulfate- and dinitrobenzene acid-induced colitis, with LASSBio-1760, LASSBio-1762, and LASSBio-1763 presenting a significant effect in both models of colitis without toxic effects. The new substances could be considered as a new prototype for the development of new anti-inflammatory treatments of colitis.

Two-Stage Strategy for Development of Proteolysis Targeting Chimeras and its Application for Estrogen Receptor Degraders

Proteolysis targeting chimeras (PROTACs) have emerged as useful chemical probes and potential therapeutics by taking advantage of the ubiquitin-proteasome system to degrade intracellular disease-associated proteins. PROTACs are heterobifunctional molecules composed of a target protein ligand, E3 ubiquitin ligase ligand, and a linker between them. The generation of efficient PROTACs requires screening of many parameters, especially the lengths and types of the linkers. We report our proof-of-concept study using a two-stage strategy to facilitate the development of PROTACs against the estrogen receptor (ER). In stage one, a library of close to 100 PROTACs was synthesized by simply mixing a library of ERα ligands containing a hydrazide functional group at different positions with a preassembled library of E3 ligase ligands bearing different types and lengths of linkers with a terminal aldehyde group in a 1:1 ratio. Cell-based screening occurred without further purification, because the formation of the acylhydrazone linkage is highly efficient and produces water as the only byproduct. Compound A3 was the most potent ER degrader in two ER+ cell lines (DC₅₀= ∼ 10 nM, D_max= ≥ 95%). Stage two involved transformation to a more stable amide linker to generate a more drug-like molecule. The new compound, AM-A3, showed comparable biological activity (DC₅₀ = 1.1 nM, D_max = 98%) and induced potent antiproliferation (IC₅₀= 13.2 nM, I_max= 69%) in MCF-7. This proof-of -concept study demonstrates that the two-stage strategy can significantly facilitate the development of PROTACs against ER without the tedious process of making large numbers of PROTACs one by one. It has the potential to be expanded to many other targets.

New 2-amino-pyridinyl-N-acylhydrazones: Synthesis and identification of their mechanism of anti-inflammatory action

AIMS

The main aim of this paper was the synthesis and the evaluation of the anti-inflammatory activity of LASSBio-1828 (an amino-pyridinyl-N-acylhydrazone) and its respective hydrochloride, based on a p38α MAPK inhibitor (LASSBio-1824) previously synthesized by our group.

MAIN METHODS

The compounds were tested regarding their cell viability effect and on acute models of inflammation such as formalin-induced licking test, cell migration and inflammatory mediators quantification.

KEY FINDINGS

Treatment with the compounds inhibited p38α, reduced inflammatory pain, cell migration and inflammatory mediators that participate on the MAPK pathway such as TNF-α and IL-1β.

SIGNIFICANCE

Taken together, these results suggest that the synthesis of the corresponding hydrochloride of LASSBio-1828 enhanced its potency as a p38 inhibitor, and also that this compound could be considered a good anti-inflammatory drug candidate after further studies.

Potent immunosuppressive activity of a phosphodiesterase-4 inhibitor N-acylhydrazone in models of lipopolysaccharide-induced shock and delayed-type hypersensitivity reaction

Immunosuppressive drugs are widely used for the treatment of immune-mediated diseases and inflammation, but the toxicity and side effects of the available immunosuppressors make the search of new agents of great relevance. Here, we evaluated the immunomodulatory activity of an N-acylhydrazone derivative, (E)-N'-(3,4-dimethoxybenzylidene)-4-methoxybenzohydrazide (LASSBio-1386), a phosphodiesterase-4 (PDE-4) inhibitor. LASSBio-1386 inhibited lymphocyte activation in a concentration-dependent fashion, decreasing lymphoproliferation and IFN-γ and IL-2 production stimulated by anti-CD3/CD28 mAbs or concanavalin A (Con A) and inducing cell-cycle arrest in the G0/G1 phase. These effects were not blocked by RU486, a glucocorticoid receptor (GR) antagonist, indicating an effect independent of glucocorticoid receptor activation. Combination index-isobologram analysis indicates a synergistic effect between LASSBio-1386 and dexamethasone in lymphoproliferation inhibition. LASSBio-1386 presented immunomodulatory action in macrophage cultures, as observed by a significant and concentration-dependent decrease in NO and TNF-α production, an effect achieved by reducing IĸB expression and NF-κB activation. In the mouse model of endotoxic shock, LASSBio-1386 at 50 and 100 mg/kg protected 50 and 85% of mice against LPS-induced lethality, respectively. In agreement to its in vitro action, treatment with 100 mg/kg of LASSBio-1386 reduced TNF-α and IL-1β serum levels, while increased IL-6 and IL-10. Finally, LASSBio-1386 reduced the paw edema in a BSA-induced delayed-type hypersensitivity model. These findings demonstrate the immunomodulatory and immunosuppressant effects of LASSBio-1386 and indicate this molecule is a promising pharmacologic agent for immune-mediated diseases.

Potent hydrazone derivatives targeting esophageal cancer cells

Hydrazone and their derivatives are a series of highly active molecules, which are widely used as lead compounds for the research and development of new anti-cancer drugs. In this study, 20 compounds were synthesized, based on this scaffold and their in vitro cytotoxicity against 6 cancer cell lines, including EC9706, SMMC-7721, MCF7, PC3, MGC-803 and EC109 was tested. Among them, compound 6p, showed strong anti-proliferative activities on esophageal carcinoma cells: EC9706 and EC109 with IC₅₀ values of 1.09 ± 0.03 and 2.79 ± 0.45 μM, respectively. 6p also significantly induces both EC9706 and EC109 cell cycle arrest at G0/G1 phase and cell apoptosis, as well as intracellular ROS accumulation, which could be markedly reversed caspase or ROS inhibitor: NAC. Meanwhile, treatment of compound 6p results in significant declined mitochondria membrane potential, increases in the expression of P53 and bax, as well as decrease in Bcl-2. 6p also activates caspase-8/9/3, PARP and Bid, indicating that 6p induces cancer cell apoptosis via the death receptor-mediated extrinsic pathway and the mitochondria-mediated intrinsic pathway. Further studies also proved that 6p does not show obvious side effects at cellular and in vivo levels. Our findings suggested that hydrazone derivative: compound 6p may serve as a lead compound for further optimization against esophageal cancer cells.

Discovery of naphthyl-N-acylhydrazone p38α MAPK inhibitors with in vivo anti-inflammatory and anti-TNF-α activity

Protein kinases constitute attractive therapeutic targets for development of new prototypes to treat different chronic diseases. Several available drugs, like tinibs, are tyrosine kinase inhibitors; meanwhile, inhibitors of serine/threonine kinases, such as mitogen-activated protein kinase (MAPK), are still trying to overcome some problems in one of the steps of clinical development to become drugs. So, here we reported the synthesis, the in vitro kinase inhibitory profile, docking studies, and the evaluation of anti-inflammatory profile of new naphthyl-N-acylhydrazone derivatives using animal models. Although all tested compounds (3a-d) have been characterized as p38α MAPK inhibitors and have showed in vivo anti-inflammatory action, LASSBio-1824 (3b) presented the best performance as p38α MAPK inhibitor, with IC₅₀  = 4.45 μm, and also demonstrated to be the most promising anti-inflammatory prototype, with good in vivo anti-TNF-α profile after oral administration.

Characterization of anti-inflammatory effect and possible mechanism of action of Tibouchina granulosa

OBJECTIVES

Tibouchina granulosa, popularly known as 'quaresmeira', belong to a genus widely used in the traditional medicine as infusions from their leaves. Other species of Tibouchina are used as antibacterial, antioxidant or antileishmanial. In this work, our objectives were to investigate the biological effects of T. granulosa in models of acute inflammation.

METHODS

Chemical analysis showed the presence of proanthocyanidins and flavonoids. Infusions from leaves of T. granulosa (1, 3, 10, 30 or 100 mg/kg) were orally administered to mice, and the anti-inflammatory effects were evaluated by the formalin-induced licking response, inhibition of carrageenan-induced cell migration into subcutaneous air pouch (SAP) and inhibition of inflammatory mediator production in inflammatory exudate collected from SAP.

KEY FINDINGS

Our data indicate that tested doses of T. granulosa infusion reduced cell migration, protein extravasated to SAP and cytokine production (i.e. TNF-α and IL-10). All doses also inhibited the first and second phase of formalin-induced licking response.

CONCLUSIONS

Taken together, our results indicate that leaves of T. granulosa present anti-inflammatory effect and can be useful in the preparation of new phytomedicines.