Chemoselective and Regiospecific Formylation of 1-Phenyl-1H-pyrazoles Through the Duff Reaction

Anti-inflammatory, antinociceptive, and vasorelaxant effects of a new pyrazole compound 5-(1-(2-fluorophenyl)-1H-pyrazol-4-yl)-1H-tetrazole: role of NO/cGMP pathway and calcium channels

Molecular modification of compounds remains important strategy towards the discovery of new drugs. In this sense, this study presents a new pyrazole derivative 5-(1-(2-fluorophenyl)-1H-pyrazol-4-yl)-1H-tetrazole (LQFM039) and evaluated the anti-inflammatory, analgesic, and vasorelaxant effects of this compound as well the mechanisms of action involved in the pharmacological effects. For this, mice were orally treated with LQFM039 (17.5, 35, or 70 mg/kg) prior acetic acid-induced abdominal writhing, formalin, tail flick, and carrageenan-induced paw edema protocols. In addition, vascular reactivity protocols were made with aortic rings contraction with phenylephrine and stimulated with graded concentrations of LQFM039. Abdominal writhing and licking time in both neurogenic and inflammatory phases of formalin were reduced with LQFM039 without altering latency to nociceptive response in the tail flick test. Carrageenan-induced paw edema showed that LQFM039 reduces edema and cell migration. In addition, the mechanism of action of LQFM039 involves NO/cGMP pathway and calcium channels, since this new pyrazole derivate elicited concentration-dependent relaxation attenuated by Nω-nitro-l-arginine methyl ester and 1H-[1,2,4] oxadiazolo [4,3-alpha]quinoxalin-1-one, and blockade of CaCl₂-induced contraction. Altogether, our finding suggests anti-inflammatory, antinociceptive, and vasorelaxant effect of this new pyrazole derivative with involvement of NO/cGMP pathway and calcium channels.

Monitoring glutathione dynamics in DNA replication (S-phase) using a two-photon reversible ratiometric fluorescent probe

The redox regulator glutathione (GSH) migrates to the nucleus to give a safeguard to DNA replication in the S-phase. The fluctuation of GSH dynamics in the cell cycle process may help to understand cancerogenesis or other abnormalities in DNA replication. For the first time, we attempted to track the time-dependent S-phase change using the newly developed ratiometric fluorescent probe Nu-GSH. This probe is highly chemoselective towards glutathione and shows an emission intensity shift from 515 nm to 455 nm. It has shown fluorescence reversibility from blue to green channels while scavenging reactive oxygen species H₂O₂. Both ratiometric fluorescence images and FACS analysis have provided quantitative information on the GSH levels in the nucleoli during DNA replication in the S-phase. Furthermore, GSH fluctuation reciprocated the decay of the S-phase on a time scale. Additionally, its two-photon ability guaranteed its capability to study GSH dynamics in live cells/tissues noninvasively. We envision that the probe Nu-GSH can be used to get high-throughput quantitative information on glutathione dynamics and give an opportunity to monitor its perturbation during the course of cell division.

Anxiolytic- and antidepressant-like effects of new phenylpiperazine derivative LQFM005 and its hydroxylated metabolite in mice

The current treatments available for anxiety and depression are only palliative. Full remission has remained elusive, characterizing unmet medical needs. In the scope of an academic drug discovery program, we describe here the design, synthesis, in vitro metabolism prediction and pharmacological characterization of a new piperazine compound, 1-(4-methoxyphenyl)-4-((1-phenyl-1H-pyrazol-4-yl)methyl)piperazine (LQFM005), and of its main putative metabolite, 4-(4-((4-(4-methoxyphenyl)piperazin-1-yl)methyl)- 1H-pyrazol-1-yl)phenol (LQFM235). The production of the metabolite was initially performed by in vitro biotransformation of LQFM005 using Aspergillus candidus and then by chemical synthesis. Oral administration of either 12 or 24 µmol/kg LQFM005 to mice did not affect spontaneous locomotor activity but increased the time spent in the center of the open field. Both LQFM005 and LQFM235 (24 µmol/kg) increased the time spent by the mice in the open arms of the elevated plus maze (EPM), a good indication of anxiolytic-like effect, and decreased the immobility time in the forced swimming test (FST), suggesting an antidepressant-like effect. The previous administration of WAY-100635 (a 5-HT_1A antagonist) abolished the effects of LQFM005 in both EPM and FST. Binding experiments showed that LQFM005 and its metabolite bind to the 5-HT_1A receptor with a moderate affinity (K_i around 5-9 µM). The two compounds are relatively safe, as indicated by cytotoxic assessment using the 3T3 fibroblast cell line and estimated LD₅₀ around 600 mg/kg. In conclusion, oral administration of the newly synthesized phenylpiperazines produced anxiolytic- and antidepressant-like effects in behavioral tests, putatively in part through the activation of 5-HT_1A receptors.

Neuropharmacological Activity of the New Piperazine Derivative 2-(4-((1- Phenyl-1H-Pyrazol-4-yl)Methyl)Piperazin-1-yl)Ethyl Acetate is Modulated by Serotonergic and GABAergic Pathways

BACKGROUND

Pharmacological treatments for mental disorders, such as anxiety and depression, present several limitations and adverse effects. Therefore, new pharmacotherapy with anxiolytic and antidepressant potential is necessary, and the study of compounds capable of interacting with more than one pharmacological target may provide new therapeutic options.

OBJECTIVES

In this study, we proposed the design, synthesis of a new compound, 2-(4-((1-phenyl-1H-pyrazol-4-yl)methyl)piperazin-1-yl)ethyl acetate (LQFM192), pharmacological evaluation of its anxiolytic-like and antidepressant-like activities, as well as the possible mechanisms of action involved.

METHODS

Administration of LQFM192 was carried out prior to the exposure of male Swiss mice to behavioral tests, such as the elevated plus-maze and forced swimming test. The involvement of the serotonergic system was studied by pretreatment with WAY-100635 or p-chlorophenylalanine (PCPA) and the involvement of the benzodiazepine site of the GABAA receptor by pretreatment with flumazenil.

RESULTS

The treatment with LQFM192 at doses of 54 and 162 µmol/kg demonstrated anxiolyticlike activity that was blocked by WAY-100635, PCPA, and flumazenil pretreatments. The potential antidepressant-like activity was visualized at the same doses and blocked by WAY-100635 and PCPA.

CONCLUSION

In summary, the anxiolytic-like activity of LQFM192 is mediated by the serotonergic system and the benzodiazepine site of the GABAA receptor, and the antidepressant-like activity through the serotonergic system.

Anti-inflammatory and antinociceptive activity profile of a new lead compound - LQFM219

LQFM219 is a molecule designed from celecoxibe (COX-2 inhibitor) and darbufelone (inhibitor of COX-2 and 5-LOX) lead compounds through a molecular hybridisation strategy. Therefore, this work aimed to investigate the antinociceptive and anti-inflammatory activities of this new hybrid compound. The acute oral systemic toxicity of LQFM219 was evaluated via the neutral red uptake assay. Acetic acid-induced abdominal writhing and CFA-induced mechanical hyperalgesia were performed to evaluate the antinociceptive activity, and the anti-oedematogenic activity was studied by CFA-induced paw oedema and croton oil-induced ear oedema. Moreover, the acute anti-inflammatory activity was determined by carrageenan-induced pleurisy. In addition, cell migration, myeloperoxidase enzyme activity, and TNF-α and IL-1β levels were determined in pleural exudate. Moreover, a redox assay was conducted using electroanalytical and DPPH methods. The results demonstrated that LQFM219 was classified as GHS category 4, and it showed better free radical scavenger activity compared to BHT. Besides, LQFM219 decreased the number of writhings induced by acetic acid and the response to the mechanical stimulus in the CFA-induced mechanical hyperalgesia test. Furthermore, LQFM219 reduced oedema formation, cell migration, and IL-1β and TNF-α levels in the pleural cavity and inhibited myeloperoxidase enzyme activity. Thus, our study provides that the new pyrazole derivative, LQFM219, demonstrated low toxicity, antinociceptive and anti-inflammatory potential in vitro and in vivo.

Design, synthesis and pharmacological assessment of new pyrazole compounds

AIMS

This study investigated the antinociceptive and anti-inflammatory effects of new pyrazole compounds LQFM011(5), LQFM043(6) and LQFM044(7) as well as the mechanisms of action and acute in vitro toxicity.

MAIN METHODS

The antinociceptive activity was evaluated using the acetic acid-induced abdominal writhing test, formalin-induced pain test and the Randall-Selitto test. The anti-inflammatory activity was evaluated using models of paw oedema and pleurisy induced by carrageenan; cell migration, the levels of tumour necrosis factor α (TNF-α) and myeloperoxidase (MPO) enzyme activity were evaluated. In addition, the ability to inhibit phospholipase A2 (PLA2) in vitro and docking in PLA2 were used. Acute oral systemic toxicity in mice was evaluated through the neutral red uptake assay.

KEY FINDINGS

The synthesised compounds (5-7), delivered via gavage (p.o.) at 70, 140 or 280 µmol/kg, decreased the number of writhings induced by acetic acid; the three compounds (280 µmol/kg p.o.) reduced the paw licking time in the first and second phase of the formalin test and decreased the nociceptive threshold variation in the Randall-Selitto test. Furthermore, this dose reduced oedema formation, leucocyte migration (specifically through reduction in polymorphonuclear cell movement) and increased mononuclear cells. MPO activity and the levels of pro-inflammatory cytokines TNF-α were decreased. Evaluation of PLA2 inhibition via the docking simulation revealed more interactions of LQFM043R(6) and LQFM044(7), data that corroborated the half-maximal inhibitory concentration (IC₅₀) of PLA2 inhibition in vitro. Therefore, LQFM011(5), LQFM043(6) and LQFM044(7) were classified with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) as category 4.

Antiangiogenic and antitumoral activity of LQFM126 prototype against B16F10 melanoma cells

Inhibition of mouse double minute 2 homolog (MDM2)-p53 interaction and reactivation of p53 signaling have been explored as effective anticancer therapeutic strategy. The potent and specific antitumor activity shown by Nutlins, first class of MDM2-p53 inhibitors discovered, has made these compounds potential antitumor candidates. To this end, we synthesized Nutlin-1 and Nutlin-2 analogs through molecular simplification and selected the compound with the most efficient antitumoral activity. Cytotoxicity of Nutlin-2 analog LQFM126 on B16F10 melanoma cells induced intense cytoplasmic vacuolization, reduction of cell size, chromatin condensation, cytoplasmic degeneration and nuclear fragmentation. LQFM126 antiproliferative effects mediated cell cycle retention in G₀/G₁ phase and increased the levels of cell cycle regulatory proteins p21 and p27. This Nutlin analog increased mitochondrial membrane potential, activated caspase-8, -9 and -3/7 and reduced VEGF levels in B16F10 cells. Therefore, LQFM126 promoted alterations suggestive of apoptosis, G0/G1 cell cycle arrest and suppression of angiogenesis through modulation of VEGF expression in B16F10 cells. Additionally, LQFM126 was classified as UN GHS category 4 (LD50 > 300-2000 mg/kg), suggesting it has low acute systemic toxicity. LQFM126 can be a promising prototype for anticancer therapy.

Molecular docking and pharmacological/toxicological assessment of a new compound designed from celecoxib and paracetamol by molecular hybridization

Nonsteroidal anti-inflammatory drugs are commonly used worldwide; however, they have several adverse effects, evidencing the need for the development of new, more effective and safe anti-inflammatory and analgesic drugs. This research aimed to design, synthesize and carry out a pharmacological/toxicological investigation of LQFM-102, which was designed from celecoxib and paracetamol by molecular hybridization. To evaluate the analgesic effect of this compound, we performed formalin-induced pain, hot plate and tail flick tests. The anti-inflammatory effect of LQFM-102 was evaluated in carrageenan-induced paw oedema and pleurisy tests. The biochemical markers indicative of toxicity-AST, ALT, GSH, urea and creatinine-as well as the index of gastric lesion after prolonged administration of LQFM-102 were also analyzed. In addition, the interaction of LQFM-102 with COX enzymes was evaluated by molecular docking. In all experimental protocols, celecoxib or paracetamol was used as a positive control at equimolar doses to LQFM-102. LQFM-102 reduced the pain induced by formalin in both phases of the test. However, this compound did not increase the latency to thermal stimuli in the hot plate and tail flick tests, suggesting an involvement of peripheral mechanisms in this effect. Furthermore, LQFM-102 reduced paw oedema, the number of polymorphonuclear cells, myeloperoxidase activity and TNF-α and IL-1β levels. Another interesting finding was the absence of alterations in the markers of hepatic and renal toxicity or lesions of gastric mucosa. In molecular docking simulations, LQFM-102 interacted with the key residues for activity and potency of cyclooxygenase enzymes, suggesting an inhibition of the activity of these enzymes.

Anti-inflammatory effect of a new piperazine derivative: (4-methylpiperazin-1-yl)(1-phenyl-1H-pyrazol-4-yl)methanone

AIMS

This study investigates the anti-nociceptive and anti-inflammatory effects of new piperazine compound (LQFM182) as well as the toxicity acute in vitro.

MAIN METHODS

To evaluate the anti-nociceptive activity, the acetic acid-induced abdominal writhing test, tail flick test and formalin-induced pain test were used. The anti-inflammatory activity was evaluated using the models of paw oedema and pleurisy induced by carrageenan and some inflammatory parameters were evaluated, including cell migration, myeloperoxidase enzyme activity and the levels of TNF-α and IL-1β cytokines in pleural exudate. The acute oral systemic toxicity of LQFM182 in mice was evaluated through the neutral red uptake (nru) assay.

KEY FINDINGS

LQFM182 (50, 100 or 200 mg/kg, p.o.) decreased the number of writhings induced by acetic acid in a dose-dependent manner, and an intermediate dose (100 mg/kg, p.o.) reduced the paw licking time of animals in the second phase of the formalin test. Furthermore, LQFM182 (100 mg/kg, p.o.) reduced oedema formation at all hours of the paw oedema induced by carrageenan test and in pleurisy test reduced cell migration from the reduction of polymorphonuclear cells, myeloperoxidase enzyme activity and the levels of pro-inflammatory cytokines IL-1β and TNF-α. Therefore, it was classified in GHS category 300 < LD₅₀ < 2000 mg/kg.

SIGNIFICANCE

Reduction of the TNF-α and IL-1β levels.

Induction of apoptosis in Ehrlich ascites tumour cells via p53 activation by a novel small-molecule MDM2 inhibitor - LQFM030

OBJECTIVE

The activation of the p53 pathway through the inhibition of MDM2 has been proposed as a novel therapeutic strategy against tumours. A series of cis-imidazoline analogues, termed nutlins, were reported to displace the recombinant p53 protein from its complex with MDM2 by binding to MDM2 in the p53 pocket, and exhibited an antitumour activity both in vitro and in vivo. Thus, the purpose of this study was to evaluate the antitumour properties of LQFM030 (2), a nutlin analogue created by employing the strategy of molecular simplification.

METHODS

LQFM030 (2) cytotoxicity was evaluated in Ehrlich ascites tumour (EAT) cells, p53 wild type, by the trypan blue exclusion test, and the mechanisms involved in EAT cell death were investigated by light and fluorescence microscopy, flow cytometry, real-time PCR and Western blotting.

KEY FINDINGS

Our results demonstrate that LQFM030 has dose-dependent antiproliferative activity and cytotoxic activity on EAT cells, induces the accumulation of p53 protein and promotes cell cycle arrest and apoptosis. p53 gene transcription was unaffected by LQFM030 (2); however, MDM2 mRNA increased and MDM2 protein decreased.

CONCLUSIONS

These results suggest that the small-molecule p53 activator LQFM030 (2) has the potential for further development as a novel cancer therapeutic agent.

Copper-Catalyzed Synthesis of Trifluoroethylarenes from Benzylic Bromodifluoroacetates

Trifluoroethylarenes are found in a variety of biologically active molecules, and strategies for accessing this substructure are important for developing therapeutic candidates and biological probes. Trifluoroethylarenes can be directly accessed via nucleophilic trifluoromethylation of benzylic electrophiles; however, current catalytic methods do not effectively transform electron-deficient substrates and heterocycles. To address this gap, we report a Cu-catalyzed decarboxylative trifluoromethylation of benzylic bromodifluoroacetates. To account for the tolerance of sensitive functional groups, we propose an inner-sphere mechanism of decarboxylation.