Design, Synthesis, and Pharmacological Evaluation of N-Acylhydrazones and Novel Conformationally Constrained Compounds as Selective and Potent Orally Active Phosphodiesterase-4 Inhibitors

Histone deacetylase inhibition mitigates cognitive deficits and astrocyte dysfunction induced by amyloid-β (Aβ) oligomers

BACKGROUND AND PURPOSE

Inhibitors of histone deacetylases (iHDACs) are promising drugs for neurodegenerative diseases. We have evaluated the therapeutic potential of the new iHDAC LASSBio-1911 in Aβ oligomer (AβO) toxicity models and astrocytes, key players in neuroinflammation and Alzheimer's disease (AD).

EXPERIMENTAL APPROACH

Astrocyte phenotype and synapse density were evaluated by flow cytometry, Western blotting, immunofluorescence and qPCR, in vitro and in mice. Cognitive function was evaluated by behavioural assays using a mouse model of intracerebroventricular infusion of AβO.

KEY RESULTS

LASSBio-1911 modulates reactivity and synaptogenic potential of cultured astrocytes and improves synaptic markers in cultured neurons and in mice. It prevents AβO-triggered astrocytic reactivity in mice and enhances the neuroprotective potential of astrocytes. LASSBio-1911 improves behavioural performance and rescues synaptic and memory function in AβO-infused mice.

CONCLUSION AND IMPLICATIONS

These results contribute to unveiling the mechanisms underlying astrocyte role in AD and provide the rationale for using astrocytes as targets to new drugs for AD.

Synthesis and activity of benzimidazole N-Acylhydrazones against Trypanosoma cruzi, Leishmania amazonensis and Leishmania infantum

In this study, we present the design, synthesis, and cytotoxic evaluation of a series of benzimidazole N-acylhydrazones against strains of T. cruzi (Y and Tulahuen) and Leishmania species (L. amazonensis and L. infantum). Compound (E)-N'-((5-Nitrofuran-2-yl)methylene)-1H-benzo[d]imidazole-2-carbohydrazide demonstrated significant activity against both trypomastigote and amastigote forms (Tulahuen strain), with an IC50/120 h of 0.033 μM and a selectivity index (SI) of 7680. This represents a potency 46 times greater than that of benznidazole (IC50/120 h = 1.520 μM, SI = 1390). Another compound (E)-N'-(2-Hydroxybenzylidene)-1H-benzo[d]imidazole-2-carbohydrazide showed promising activity against both trypomastigote and amastigote forms (Tulahuen strain), with an IC50/120 h of 3.600 μM and an SI of 14.70. However, its efficacy against L. infantum and L. amazonensis was comparatively lower. These findings provide valuable insights for the development of more effective treatments against Trypanosoma cruzi.

Development of Novel N-Acylhydrazone Derivatives with High Anti-obesity Activity and Improved Safety by Exploring the Pharmaceutical Properties of Aldehyde Group

The discovery of effective and safe antiobesity agents remains a challenging yet promising field. Our previous studies identified Bouchardatine derivatives as potential antiobesity agents. However, the 8a-aldehyde moiety rendered them unsuitable for drug development. In this study, we designed two series of novel derivatives to modify this structural feature. Through a structure-activity relationship study, we elucidated the role of the 8a-aldehyde group in toxicity induction. We identified compound 14d, featuring an 8a-N-acylhydrazone moiety, which exhibited significant lipid-lowering activity and reduced toxicity. Compound 14d shares a similar lipid-lowering mechanism with our lead compound 3, but demonstrates improved pharmacokinetic properties and safety profile. Both oral and injectable administration of 14d significantly reduced body weight gain and ameliorated metabolic syndrome in diet-induced obese mice. Our findings identify 14d as a promising antiobesity agent and highlight the potential of substituting the aldehyde group with an N-acylhydrazone to enhance drug-like properties.

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.

Stereochemical insights into β-amino-N-acylhydrazones and their impact on DPP-4 inhibition

Dipeptidyl peptidase IV (DPP-4) is a key enzyme that regulates several important biological processes and it is better known to be targeted by gliptins as a modern validated approach for the management of type 2 diabetes mellitus (T2DM). However, new generations of DPP-4 inhibitors capable of controlling inflammatory processes associated with chronic complications of T2DM are still needed. In this scenario, we report here the design by molecular modelling of new β-amino-N-acylhydrazones, their racemic synthesis, chiral resolution, determination of physicochemical properties and their DPP4 inhibitory potency. Theoretical and experimental approaches allowed us to propose a preliminary SAR, as well as to identify LASSBio-2124 (6) as a new lead for DPP-4 inhibition, with good physicochemical properties, favourable eudismic ratio, scalable synthesis and anti-diabetes effect in a proof-of-concept model. These findings represent an interesting starting point for the development of a new generation of DPP-4 inhibitors, useful in the treatment of T2DM and comorbidities.

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.

Rh(III) Catalyzed Redox-Neutral C-H Activation/[5 + 2] Annulation of Aroyl Hydrazides and Sulfoxonium Ylides: Synthesis of Benzodiazepinones

We herein report the Rh(III) catalyzed redox-neutral C-H activation/[5 + 2] annulation of aroyl hydrazides with sulfoxonium ylides as safe carbene precursors. The reaction shows excellent functional group tolerance, broad substrate scope, and scalability. We demonstrated the synthetic utility of the protocol via the synthesis of various diazepam drug analogues, late-stage functionalization of probenecid drug, and large scale synthesis. Finally, kinetic studies revealed C-H activation as the rate-determining step.

The Magic Methyl and Its Tricks in Drug Discovery and Development

One of the key scientific aspects of small-molecule drug discovery and development is the analysis of the relationship between its chemical structure and biological activity. Understanding the effects that lead to significant changes in biological activity is of paramount importance for the rational design and optimization of bioactive molecules. The "methylation effect", or the "magic methyl" effect, is a factor that stands out due to the number of examples that demonstrate profound changes in either pharmacodynamic or pharmacokinetic properties. In many cases, this has been carried out rationally, but in others it has been the product of serendipitous observations. This paper summarizes recent examples that provide an overview of the current state of the art and contribute to a better understanding of the methylation effect in bioactive small-molecule drug candidates.

Anticancer agents incorporating the N-acylhydrazone scaffold: Progress from 2017 to present

The N-acylhydrazone motif has been shown to be particularly adaptable and promising in the area of medicinal chemistry and drug development, due to its significant biological and pharmacological characteristics. Moreover, N-acylhydrazones are appealing synthetic and biological tools because of their simple and straightforward synthesis. This scaffold has emerged as a fundamental building block for the synthesis of bioactive compounds. Particularly, the N-acylhydrazone scaffold served as a base for the synthesis of a number of potent anticancer agents acting via different mechanisms. An updated summary of the anticancer activity of N-acylhydrazone derivatives described in the literature (from 2017 to 2022) is provided in the current review. It discusses the structure-activity relationship (SAR) of N-acylhydrazone derivatives exhibiting anticancer potential, which could be helpful in designing and developing new derivatives as effective antiproliferative candidates in the future.

A Ag2CO3/TFA-catalyzed intramolecular annulation approach to imidazo[1,2-c][1,3]oxazin-5-one derivatives

A series of 2,7-disubstituted 3-methylimidazo[1,2-c][1,3]oxazin-5-ones were synthesized in good yields via Ag₂CO₃/TFA-mediated intramolecular annulation of N-Boc-2-alkynyl-4-bromo(alkynyl)-5-methylimidazoles. This methodology was carried out in the presence of a catalytic amount of silver carbonate and trifluoroacetic acid in dichloroethane at 60 °C. In all experiments, only the six-membered ring product was obtained since the possible five-membered compound was not observed, proving the high regioselectivity of this approach. A complementary computational study was performed in order to rationalize the mechanism of 6-endo-dig heterocycle formation. In addition, 2-bromo-3-methyl-7-phenylimidazo[1,2-c][1,3]oxazin-5-one was used as a building block to synthesize a small library of new 2-substituted imidazo[1,2-c][1,3]oxazin-5-one derivatives through the Suzuki, Sonogashira and Heck cross coupling reactions.

The Design of Multi-target Drugs to Treat Cardiovascular Diseases: Two (or more) Birds on one Stone

Cardiovascular diseases (CVDs) comprise a group of diseases and disorders of the heart and blood vessels, which together are the number one cause of death worldwide, being associated with multiple genetic and modifiable risk factors, and that may directly arise from different etiologies. For a long time, the search for cardiovascular drugs was based on the old paradigm "one compound - one target", which aims to obtain a highly potent and selective molecule with only one desired molecular target. Although historically successful in the last decades, this approach ignores the multiple causes and the multifactorial nature of CVD's. Thus, over time, treatment strategies for cardiovascular diseases have changed and, currently, pharmacological therapies for CVD are mainly based on the association of two or more drugs to control symptoms and reduce cardiovascular death. In this context, the development of multitarget drugs, i.e, compounds having the ability to act simultaneously at multiple sites, is an attractive and relevant strategy that can be even more advantageous to achieve predictable pharmacokinetic and pharmacodynamics correlations as well as better patient compliance. In this review, we aim to highlight the efforts and rational pharmacological bases for the design of some promising multitargeted compounds to treat important cardiovascular diseases like heart failure, atherosclerosis, acute myocardial infarction, pulmonary arterial hypertension and arrhythmia.

Antiallodynic action of phosphodiesterase inhibitors in a mouse model of peripheral nerve injury

Neuropathic pain arises as a consequence of a lesion or disease affecting the somatosensory nervous system. It is accompanied by neuronal and non-neuronal alterations, including alterations in intracellular second messenger pathways. Cellular levels of 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) are regulated by phosphodiesterase (PDE) enzymes. Here, we studied the impact of PDE inhibitors (PDEi) in a mouse model of peripheral nerve injury induced by placing a cuff around the main branch of the sciatic nerve. Mechanical hypersensitivity, evaluated using von Frey filaments, was relieved by sustained treatment with the non-selective PDEi theophylline and ibudilast (AV-411), with PDE4i rolipram, etazolate and YM-976, and with PDE5i sildenafil, zaprinast and MY-5445, but not by treatments with PDE1i vinpocetine, PDE2i EHNA or PDE3i milrinone. Using pharmacological and knock-out approaches, we show a preferential implication of delta opioid receptors in the action of the PDE4i rolipram and of both mu and delta opioid receptors in the action of the PDE5i sildenafil. Calcium imaging highlighted a preferential action of rolipram on dorsal root ganglia non-neuronal cells, through PDE4B and PDE4D inhibition. Rolipram had anti-neuroimmune action, as shown by its impact on levels of the pro-inflammatory cytokine tumor necrosis factor-α (TNFα) in the dorsal root ganglia of mice with peripheral nerve injury, as well as in human peripheral blood mononuclear cells (PBMCs) stimulated with lipopolysaccharides. This study suggests that PDEs, especially PDE4 and 5, may be targets of interest in the treatment of neuropathic pain.

Effect of S-Se Bioisosteric Exchange on Affinity and Intrinsic Efficacy of Novel N-acylhydrazone Derivatives at the Adenosine A2A Receptor

In this work, we evaluated the conformational effect promoted by the isosteric exchange of sulfur by selenium in the heteroaromatic ring of new N-acylhydrazone (NAH) derivatives (3-8, 13, 14), analogues of the cardioactive compounds LASSBio-294 (1) and LASSBio-785 (2). NMR spectra analysis demonstrated a chemical shift variation of the iminic Csp2 of NAH S/Se-isosters, suggesting a stronger intramolecular chalcogen interaction for Se-derivatives. To investigate the pharmacological profile of these compounds at the adenosine A2A receptor (A2AR), we performed a previously validated functional binding assay. As expected for bioisosteres, the isosteric-S/Se replacement affected neither the affinity nor the intrinsic efficacy of our NAH derivatives (1-8). However, the N-methylated compounds (2, 6-8) presented a weak partial agonist profile at A2AR, contrary to the non-methylated counterparts (1, 3-5), which appeared as weak inverse agonists. Additionally, retroisosterism between aromatic rings of NAH on S/Se-isosters mimicked the effect of the N-methylation on intrinsic efficacy at A2AR, while meta-substitution in the phenyl ring of the acyl moiety did not. This study showed that the conformational effect of NAH-N-methylation and aromatic rings retroisosterism changed the intrinsic efficacy on A2AR, indicating the S/Se-chalcogen effect to drive the conformational behavior of this series of NAH.

New 2,3-Benzodiazepine Derivative: Synthesis, Activity on Central Nervous System, and Toxicity Study in Mice

We report the design and synthesis of a new diazepine derivative, 4-(4-methoxyphenyl)-2,3,4,5-tetrahydro-2,3-benzodiazepin-1-one (VBZ102), and the evaluation of its anxiolytic-like profile, memory impairment effect, and toxicity in Swiss mice. VBZ102 was evaluated for central nervous system effects in an open field, light–dark box, and novel object recognition tests under oral administration for acute and sub-acute treatment. We tested the VBZ102 toxicity in mice through a determination of LD₅₀ values and examination of the biochemical and histopathological parameters. The VBZ102 induced an anxiolytic effect at different doses both in the light–dark box and open field tests. Unlike other benzodiazepines (e.g., bromazepam), a sedative effect was noted only after administration of the VBZ102 at 10.0 mg/kg.

Structure and biological profile of transition metal complexes with (E)-4-(2-(pyridin-2-ylmethylene)hydrazinyl)quinazoline

The interaction of the recently reported quinazoline derivative (E)-4-(2-(pyridin-2-ylmethylene)hydrazinyl)quinazoline (L) with a series of metal(II) (= copper(II), nickel(II), cobalt(II) and cadmium(II)) chlorides or nitrates resulted in the formation of mononuclear complexes which were characterized by spectroscopic techniques and single-crystal X-ray crystallography, i.e. [Cu(L)₂]Cl₂·4H₂O (1·4H₂O), [Ni(L)₂]Cl₂·4H₂O (2·4H₂O), [Ni(L)₂](NO₃)₂·MeOH (3·MeOH), [Co(L)₂]Cl₂·4H₂O (4·4H₂O), [Co(L)₂](NO₃)₂·H₂O (5·H₂O), [Co(L)₂](NO₃)₃·2.5H₂O (6·2.5H₂O), [Cd(L)(Cl)₂]·H₂O (7·H₂O) and [Cd(L)(CH₃OH)(H₂O)(NO₃)](NO₃) (8). The biological profile of the complexes was further assessed in regard to their binding affinity with calf-thymus DNA, their cleavage ability towards pBluescript II KS plasmid DNA in the absence or presence of irradiation of various wavelengths, their interaction with bovine serum albumin and finally, their ability to scavenge 1,1-diphenyl-picrylhydrazyl and 2,2΄-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and to reduce H₂O₂.

Design, Synthesis and Anticandidal Evaluation of Indazole and Pyrazole Derivatives

Candidiasis, caused by yeasts of the genus Candida, is the second cause of superficial and mucosal infections and the fourth cause of bloodstream infections. Although some antifungal drugs to treat candidiasis are available, resistant strains to current therapies are emerging. Therefore, the search for new candicidal compounds is certainly a priority. In this regard, a series of indazole and pyrazole derivatives were designed in this work, employing bioisosteric replacement, homologation, and molecular simplification as new anticandidal agents. Compounds were synthesized and evaluated against C. albicans, C. glabrata, and C. tropicalis strains. The series of 3-phenyl-1H-indazole moiety (10a–i) demonstrated to have the best broad anticandidal activity. Particularly, compound 10g, with N,N-diethylcarboxamide substituent, was the most active against C. albicans and both miconazole susceptible and resistant C. glabrata species. Therefore, the 3-phenyl-1H-indazole scaffold represents an opportunity for the development of new anticandidal agents with a new chemotype.

Cardiopreventive capacity of a novel (E)-N'-(1-(7-methoxy-2-oxo-2H-chromen-3-yl) ethylidene)-4-methylbenzenesulfonohydrazide against isoproterenol-induced myocardial infarction by moderating biochemical, oxidative stress, and histological parameters

This study is carried out to assess the cardiopreventive effect of (E)-N'-(1-(7-methoxy-2-oxo-2H-chromen-3-yl) ethylidene)-4-methylbenzenesulfonohydrazide or SHC, a novel synthesized coumarin, against myocardial infarction induced by isoproterenol (ISO). The SHC compound was identified and characterized by spectral methods (infrared, ¹ H NMR [nuclear magnetic resonance], ¹³ C NMR, Nuclear Overhauser Effect Spectroscopy, and high-resolution mass spectroscopy). Male Wistar rats were divided into four groups: Control, ISO (rats were injected subcutaneously by 85 mg/kg body weight [BW] of isoproterenol at Days 6 and 7 of the experience), ISO + SHC (150 µg/kg BW, orally for 7 days) and ISO + acenocoumarol (150 µg/kg BW, orally for 7 days). Results showed that ISO induced a remarkable alteration of electrocardiogram (ECG) pattern and increases of plasma cardiac troponin T, creatine kinase-MB, total cholesterol, triglycerides, low-density lipoprotein-cholesterol, lactate dehydrogenase, aspartate transaminase, and malondialdehyde. In addition, ISO reduced the high-density lipoprotein-cholesterol content and the activities of superoxide dismutase and glutathione peroxidase, with the induction of myocardial necrosis. However, SHC administration revealed a significant decrease in cardiac dysfunction markers, restored normal ECG pattern, as well as improving lipids parameters. Moreover, SHC treatment remarkably alleviated the cardiac oxidative stress and the myocardial remodeling process. Overall, the SHC offers good protection from acute myocardial infarction through the antioxidant capacity.

In Vitro, In Vivo and In Silico Effectiveness of LASSBio-1386, an N-Acyl Hydrazone Derivative Phosphodiesterase-4 Inhibitor, Against Leishmania amazonensis

Leishmaniasis are group of neglected diseases with worldwide distribution that affect about 12 million people. The current treatment is limited and may cause severe adverse effects, and thus, the search for new drugs more effective and less toxic is relevant. We have previously investigated the immunomodulatory effects of LASSBio-1386, an N-acylhydrazone derivative. Here we investigated the in vitro and in vivo activity of LASSBio-1386 against L. amazonensis. LASSBio-1386 inhibited the proliferation of promastigotes of L. amazonensis (EC₅₀ = 2.4 ± 0.48 µM), while presenting low cytotoxicity to macrophages (CC₅₀ = 74.1 ± 2.9 µM). In vitro incubation with LASSBio-1386 reduced the percentage of Leishmania-infected macrophages and the number of intracellular parasites (EC₅₀ = 9.42 ± 0.64 µM). Also, in vivo treatment of BALB/c mice infected with L. amazonensis resulted in a decrease of lesion size, parasitic load and caused histopathological alterations, when compared to vehicle-treated control. Moreover, LASSBio-1386 caused ultrastructural changes, arrested cell cycle in G0/G1 phase and did not alter the membrane mitochondrial potential of L. amazonensis. Aiming to its possible molecular interactions, we performed docking and molecular dynamics studies on Leishmania phosphodiesterase B1 (PDB code: 2R8Q) and LASSBio-1386. The computational analyses suggest that LASSBio-1386 acts against Leishmania through the modulation of leishmanial PDE activity. In conclusion, our results indicate that LASSBio-1386 is a promising candidate for the development of new leishmaniasis treatment.

The long and winding road of designing phosphodiesterase inhibitors for the treatment of heart failure

Cyclic nucleotide phosphodiesterases (PDEs) are a superfamily of enzymes known to play a critical role in the indirect regulation of several intracellular metabolism pathways through the selective hydrolysis of the phosphodiester bonds of specific second messenger substrates such as cAMP (3',5'-cyclic adenosine monophosphate) and cGMP (3',5'-cyclic guanosine monophosphate), influencing the hypertrophy, contractility, apoptosis and fibroses in the cardiovascular system. The expression and/or activity of multiple PDEs is altered during heart failure (HF), which leads to changes in levels of cyclic nucleotides and function of cardiac muscle. Within the cardiovascular system, PDEs 1-5, 8 and 9 are expressed and are interesting targets for the HF treatment. In this comprehensive review we will present a briefly description of the biochemical importance of each cardiovascular related PDE to the HF, and cover almost all the "long and winding road" of designing and discovering ligands, hits, lead compounds, clinical candidates and drugs as PDE inhibitors in the last decade.

Salviplenoid A from Salvia plebeia attenuates acute lung inflammation via modulating NF-κB and Nrf2 signaling pathways

Acute lung injury (ALI) involves series of inflammatory pathologies and cause high morbidity. Salviplenoid A (SA) was a new sesquiterpenoid from the traditional inflammatory herb Salvia plebeia. In our previous study, SA exhibited antiinflammatory activity in RAW264.7 cells. However, the extensive effects of SA in human cells and in vivo and the active mechanisms are unclear. Thus, in this study, we sought to access its effects in vitro and in vivo and to investigate its mechanisms. SA was proved to inhibit the induction of proinflammatory cytokines in human cell types, including pulmonary epithelial cells and endothetial cells. It also depressed monocyte adhesion. Moreover, SA potently attenuated the acute lung inflammation in the LPS-induced mouse model shown by down-regulation of proinflammatory mediators, inhibition of polymorphonuclear neutrophil infiltration, and alleviation of related symptoms like alveolar congestion and mucus secretion. Further evaluation confirmed that SA regulated NF-κB pathway by inhibiting the IκB-α phosphorylation. And it markedly mediated Nrf2/HO-1 pathway by activating the Nrf2/HO-1 expression and promoting Nrf2 nuclear translocation. Therefore, SA could attenuate acute lung inflammation via suppressing NF-κB and activating Nrf2, which provide a theoretical basis for the potential application of SA in clinic.

Synthesis of 4-Alkylated Isocoumarins via Pd-Catalyzed α-Arylation Reaction

A convergent method for the rapid preparation of substituted isocoumarins is reported. The transformation takes advantage of a spontaneous intramolecular cyclization that follows the Pd-catalyzed α-arylation of aldehydes with 2-halobenzoic esters. The reaction uses an air-stable, single-component palladium catalyst and provides access to 4-alkylated isocoumarins in one step from commercial starting materials. The applicability of the method using both cyclic and linear ketones as well as transformations of the isocoumarin core is also demonstrated.

Discovery of sulfonyl hydrazone derivative as a new selective PDE4A and PDE4D inhibitor by lead-optimization approach on the prototype LASSBio-448: In vitro and in vivo preclinical studies

Phosphodiesterase 4 (PDE4) inhibitors have emerged as a new strategy to treat asthma and other lung inflammatory diseases. Searching for new PDE4 inhibitors, we previously reported the discover of LASSBio-448, a sulfonamide with potential to prevent and reverse pivotal pathological features of asthma. In this paper, two novel series of sulfonamide (6a-6m) and sulfonyl hydrazone (7a-7j) analogues of LASSBio-448 have been synthetized and evaluated for selective inhibitory activity toward cAMP-specific PDE4 isoforms. From these studies, we have identified 7j (LASSBio-1632) as a new anti-asthmatic lead-candidate associated with selective inhibition of PDE4A and PDE4D isoenzymes and blockade of airway hyper-reactivity (AHR) and TNF-α production in the lung tissue. In addition, it was able to relax guinea pig trachea on non-sensitized and sensitized animals and showed great TGI permeability.

4-Hydroxy-3-methylbenzofuran-2-carbohydrazones as novel LSD1 inhibitors

Histone lysine specific demethylase 1 (LSD1 or KDM1A) is a potential therapeutic target in oncology due to its overexpression in various human tumors. We report herein a new class of benzofuran acylhydrazones as potent LSD1 inhibitors. Among the 31 compounds prepared, 14 compounds exhibited excellent LSD1 inhibitory activity with IC₅₀ values ranging from 7.2 to 68.8 nM. In cellular assays, several compounds inhibited the proliferations of various cancer cell lines, including PC-3, MCG-803, U87 MG, PANC-1, HT-29 and MCF-7. This opens up the opportunity for further optimization and investigation of this class compounds for potential cancer treatment.

New Hybrid Pyrazole and Imidazopyrazole Antinflammatory Agents Able to Reduce ROS Production in Different Biological Targets

Several anti-inflammatory agents based on pyrazole and imidazopyrazole scaffolds and a large library of substituted catechol PDE4D inhibitors were reported by us in the recent past. To obtain new molecules potentially able to act on different targets involved in inflammation onset we designed and synthesized a series of hybrid compounds by linking pyrazole and imidazo-pyrazole scaffolds to differently decorated catechol moieties through an acylhydrazone chain. Some compounds showed antioxidant activity, inhibiting reactive oxygen species (ROS) elevation in neutrophils, and a good inhibition of phosphodiesterases type 4D and, particularly, type 4B, the isoform most involved in inflammation. In addition, most compounds inhibited ROS production also in platelets, confirming their ability to exert an antiinflammatory response by two independent mechanism. Structure-activity relationship (SAR) analyses evidenced that both heterocyclic scaffolds (pyrazole and imidazopyrazole) and the substituted catechol moiety were determinant for the pharmacodynamic properties, even if hybrid molecules bearing to the pyrazole series were more active than the imidazopyrazole ones. In addition, the pivotal role of the catechol substituents has been analyzed. In conclusion the hybridization approach gave a new serie of multitarget antiinflammatory compounds, characterized by a strong antioxidant activity in different biological targets.

Design, Synthesis, and Pharmacological Evaluation of First-in-Class Multitarget N-Acylhydrazone Derivatives as Selective HDAC6/8 and PI3Kα Inhibitors

Targeting histone deacetylases (HDACs) and phosphatidylinositol 3-kinases (PI3Ks) is a very promising approach for cancer treatment. This manuscript describes the design, synthesis, in vitro pharmacological profile, and molecular modeling of a novel class of N-acylhydrazone (NAH) derivatives that act as HDAC6/8 and PI3Kα dual inhibitors. The surprising selectivity for PI3Kα may be related to differences in the conformation in the active site. Cellular studies showed that these compounds act in HDAC6 inhibition and the PI3/K/AKT/mTOR pathway. The compounds that are selective for inhibition of HDAC6/8 and inhibit PI3Kα show potential for the treatment of cancer.

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.

Sagrillo F, R. Freitas MC, A. Alves M, Thota S, Tinoco LW, Magalhães A, Sant’Anna CMR, Fraga CAM. Structure–property relationship studies of 3-acyl-substituted furans: the serendipitous identification and characterization of a new non-classical hydrogen bond donor moiety

A serendipitous identification and characterization of a new non-classical hydrogen bond donor moiety found in N-acylhydrazones containing 3-acyl-substituted furan subunit is presented.

Recent advances in the pharmacological diversification of quinazoline/quinazolinone hybrids

Due to the pharmacological activities of quinazoline and quinazolinone scaffolds, it has aroused great interest in medicinal chemists for the development of new drugs or drug candidates. The pharmacological activities of quinazoline and its related scaffolds include anti-cancer, anti-microbial, anti-convulsant, and antihyperlipidaemia. Recently, molecular hybridization technology is used for the development of hybrid analogues with improved potency by combining two or more pharmacophores of bioactive scaffolds. The molecular hybridization of various biologically active pharmacophores with quinazoline derivatives resulted in lead compounds with multi-faceted biological activity wherein specific as well as multiple targets were involved. The present review summarizes the advances in lead compounds of quinazoline hybrids and their related heterocycles in medicinal chemistry. Moreover, the review also helps to intensify the drug development process by providing an understanding of the potential role of these hybridized pharmacophoric features in exhibiting various pharmacological activities.

Recent advances in quinazoline/quinazolinone hybrid heterocycles in medicinal chemistry and their pharmacological diversification.

NHC-catalyzed β-specific addition of N-based nucleophiles to allenoates

N-heterocyclic carbene (NHC) catalyzed reactions of nitrogenous heterocycles or trifluoromethylated acylhydrazone with allenoates gave regiospecific β-adducts. DFT calculations rationalized the origination of regio- and E/Z selectivities.

A Novel Conjugate of Bis[((4-bromophenyl)amino)quinazoline], a EGFR-TK Ligand, with a Fluorescent Ru(II)-Bipyridine Complex Exhibits Specific Subcellular Localization in Mitochondria

The epidermal growth factor receptor (EGFR) is a key target in anticancer research, whose aberrant function in malignancies has been linked to severe irregularities in critical cellular processes, including cell cycle progression, proliferation, differentiation, and survival. EGFR mutant variants, either transmembrane or translocated to the mitochondria and/or the nucleus, often exhibit resistance to EGFR inhibitors. The ability to noninvasively image and quantify EGFR provides novel approaches in the detection, monitoring, and treatment of EGFR-related malignancies. The current study aimed to deliver a new theranostic agent that combines fluorescence imaging properties with EGFR inhibition. This was achieved via conjugation of an in-house-developed ((4-bromophenyl)amino)quinazoline inhibitor of mutant EGFR-TK, selected from a focused aminoquinazoline library, with a [Ru(bipyridine)₃]²⁺ fluorophore. A triethyleneglycol-derived diamino linker featuring (+)-ionizable sites was employed to link the two functional moieties, affording two unprecedented Ru conjugates with 1:1 and 2:1 stoichiometry of aminoquinazoline to the Ru complex (mono-quinazoline-Ru-conjugate and bis-quinazoline-Ru-conjugate, respectively). The bis-quinazoline-Ru-conjugate, which retains an essential inhibitory activity, was found by fluorescence imaging to be effectively uptaken by Uppsala 87 malignant glioma (grade IV malignant glioma) cells. The fluorescence imaging study and a time-resolved fluorescence resonance energy transfer study indicated a specific subcellular distribution of the conjugate that coincides with that of a mitochondria-targeted dye, suggesting mitochondrial localization of the conjugate and potential association with mitochondria-translocated forms of EGFR. Mitochondrial localization was further documented by the specific concentration of the bis-quinazoline-Ru-conjugate in a mitochondrial isolation assay.

Design and synthesis of 1,2,4-triazolo[1,5-a]pyrimidine derivatives as PDE 4B inhibitors endowed with bronchodilator activity

A series of 1,2,4-triazolo[1,5-a]pyrimidine derivatives was designed, synthesized, and screened for their phosphodiesterase (PDE 4B) inhibitory activity and bronchodilation ability. Compound 7e showed 41.80% PDE 4B inhibition at 10 µM. Eight compounds were screened for their bronchodilator activity, where compounds 7f and 7e elicited promising bronchodilator activity with EC₅₀ values of 18.6 and 57.1 µM, respectively, compared to theophylline (EC₅₀  = 425 µM). Molecular docking at the PDE 4B active site revealed a binding mode and docking scores comparable to those of a reference ligand, consistent with their PDE 4B inhibition activity.

Orally delivered resveratrol-loaded lipid-core nanocapsules ameliorate LPS-induced acute lung injury via the ERK and PI3K/Akt pathways

Background

Resveratrol (RSV) has attracted interest as an alternative drug for the treatment of acute lung injury (ALI) and other pulmonary diseases, but its poor oral bioavailability is a limitation. In this study, we employed drug delivery nanotechnology to improve the stability, lung localization and efficacy of orally administered resveratrol to control lung damage leading to ALI.

Methods and materials

RSV-loaded lipid-core nanocapsules (RSV-LNCs), prepared by interfacial deposition of biodegradable polymers, were given orally to A/J mice prior to lipopolysaccharide (LPS) intranasal instillation. Inflammatory changes, oxidative stress and lung tissue elastance were assessed 24 h after LPS challenge.

Results

RSV-LNCs (5 mg/kg), given 1, 4, 6 or 12 h but not 24 h before provocation, inhibited LPS-induced leukocyte accumulation in the bronchoalveolar fluid (BALF), whereas unloaded nanocapsules (ULNCs) or free RSV (5 mg/kg) were ineffective. RSV-LNCs (2.5–10 mg/kg) but not ULNCs or RSV improved lung function and prevented total leukocyte and neutrophil accumulation equally in both BALF and lung tissue when given 4 h before LPS challenge. Similar findings were seen concerning the generation of a range of pro-inflammatory cytokines such as IL-6, KC, MIP-1α, MIP-2, MCP-1 and RANTES in lung tissue. In addition, only RSV-LNCs inhibited MDA levels and SOD activity in parallel with blockade of the ERK and PI3K/Akt pathways following LPS provocation.

Conclusion

Nanoformulation of RSV in biodegradable oil-core polymers is an effective strategy to improve the anti-ALI activity of RSV, suggesting that the modified-release formulation of this plant polyphenol may be of great value in clinical conditions associated with ALI and respiratory failure.

Tin Powder-Promoted Cascade Condensation/Allylation/Lactamization: Synthesis of Isoindolinones and Pyrazoloisoindol-8-ones

An efficient tin powder-promoted cascade condensation/allylation/lactamization of 2-formylbenzoic acids, hydrazides, and allyl bromides was developed for the synthesis of isoindolinones in good to excellent yields under mild conditions without any other additives or catalysts. Further manipulation of isoindolinones by iodocyclization process afforded the tricyclic tetrahydro-8 H-pyrazolo[5,1- a]isoindol-8-one derivatives, which could be converted into more complicated tetracyclic tetrahydro-4 H-azirino[1',2':2,3]pyrazolo[5,1- a]isoindol-4-ones.

Base-promoted regiodivergent allylation of N-acylhydrazones with Morita–Baylis–Hillman carbonates by tuning the catalyst

A catalyst-controlled regiodivergent allylation reaction of N-acylhydrazones (NAHs) with Morita–Baylis–Hillman (MBH) carbonates has been developed, paving a new avenue for the diversification of NAH.