New platelet aggregation inhibitors based on pyridazinone moiety

Pyridazine and pyridazinone derivatives: Synthesis and in vitro investigation of their anti-inflammatory potential in LPS-induced RAW264.7 macrophages

New pyridazine and pyridazinone derivatives 3a-g, 4a-f, 6a, and 6b were designed and synthesized. Cell viability of all compounds was established based on the viability of lipopolysaccharide-induced RAW264.7 macrophage cells determined via the MTT assay. In vitro inhibition assays on human COX-1 and COX-2 enzymes were conducted to probe the newly synthesized compounds' anti-inflammatory activity. The half maximal inhibitory concentration values for the most active compounds, 3d, 3e, and 4e towards COX-2 were 0.425, 0.519, and 0.356 µM, respectively, in comparison with celecoxib. The newly synthesized compounds' ability to inhibit the production of certain proinflammatory cytokines, such as inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-6, and prostaglandin-E2, was also estimated in lipopolysaccharide-induced macrophages (RAW264.7 cells). Compounds 3d and 3e were identified as the most potent cytokine production inhibitors. The results of molecular modeling studies suggested that these compounds were characterized by a reasonable binding affinity toward the active site of COX-2, when compared to a reference ligand. These results might be taken into consideration in further investigations into new anti-inflammatory agents.

Synthesis, crystal structure, DFT, Hirshfeld surface analysis, energy framework, docking and molecular dynamic simulations of (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one as anticancer agent

In this work, a novel crystal, (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one (E-BSP) was synthesized via Knoevenagel condensation of benzaldehyde and (E)-6-(4-methoxystyryl)-4,5-dihydropyridazin-3(2H)-one. The molecular structure of E-BSP was confirmed by using FT-IR, 1H-NMR, 13C-NMR, UV-vis, ESI-MS, TGA/DTA thermal analyses and single crystal X-ray diffraction. The DFT/B3LYP methods with the 6-311++G(d,p) basis set were used to determine the vibrational modes over the optimized structure. Potential energy distribution (PED) and the VEDA 4 software were used to establish the theoretical mode assignments. The same approach was used to compute the energies of frontier molecular orbitals (HOMO-LUMO), global reactivity descriptors, and molecular electrostatic potential (MEP). Additionally, experimental and computed UV spectral parameters were determined in methanol and the obtained outputs were supported by FMO analysis. Molecular docking and molecular dynamics (MD) simulation analyses of the E-BSP against six proteins obtained from different cancer pathways were carried out. The proteins include; epidermal growth factor receptor (EGFR), Estrogen receptor (ERα), Mammalian target of rapamycin (mTOR), Progesterone receptor (PR) (Breast cancer), Human cyclin-dependent kinase 2 (CDK2) (Colorectal cancer), and Survivin (Squamous cell carcinoma/Non-small cell lung cancer). The results of the analyses showed that the compound had less binding energies ranging between -6.30 to -9.09 kcal/mol and formed stable complexes at the substrate-binding site of the proteins after the 50 ns MD simulation. Therefore, E-BSP was considered a potential inhibitor of different cancer pathways and should be used for the treatment of cancer after experimental validation and clinical trial.Communicated by Ramaswamy H. Sarma.

Novel Pyridazin-3(2H)-one-Based Guanidine Derivatives as Potential DNA Minor Groove Binders with Anticancer Activity

Novel aryl guanidinium analogues containing the pyridazin-3(2H)-one core were proposed as minor groove binders (MGBs) with the support of molecular docking studies. The target dicationic or monocationic compounds, which show the guanidium group at different positions of the pyridazinone moiety, were synthesized using the corresponding silyl-protected pyridazinones as key intermediates. Pyridazinone scaffolds were converted into the adequate bromoalkyl derivatives, which by reaction with N,N'-di-Boc-protected guanidine followed by acid hydrolysis provided the hydrochloride salts 1-14 in good yields. The ability of new pyridazin-3(2H)-one-based guanidines as DNA binders was studied by means of DNA UV-thermal denaturation experiments. Their antiproliferative activity was also explored in three cancer cell lines (NCI-H460, A2780, and MCF-7). Compounds 1-4 with a bis-guanidinium structure display a weak DNA binding affinity and exhibit a reasonable cellular viability inhibition percentage in the three cancer cell lines studied.

Pyridazinones containing dithiocarbamoyl moieties as a new class of selective MAO-B inhibitors

A novel class of potential MAO-B inhibitors was designed and synthesized in good yield by combining the pyridazinone moiety with the dithiocarbamate framework, two relevant pharmacophores for drug discovery. The biological results obtained for the different pyridazinone/dithiocarbamate hybrids (compounds 8-14) indicated that most of them reversibly and selectively inhibit the hMAO-B in vitro with IC₅₀ values in the µM range and exhibit not significant cellular toxicity. The analogues 9a₁, 11a₁, 12a₂, 12b₁ and 12b₂, which present the dithiocarbamate fragment derivatized with a piperidin-1-yl or pyrrolidin-1-yl group and placed at C3 or C4 of the diazine ring, were the most attractive compounds of these series. Molecular modeling studies were performed to analyze the binding mode to the enzyme and the structure activity relationships of the titled compounds, as well as to predict their drug-like properties.

Synthesis, spectroscopy, crystal structure, TGA/DTA study, DFT and molecular docking investigations of (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one

In this study, we present the synthesis of novel pyridazin-3(2H)-one derivative namely (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one (MBSP). The chemical structure of MBSP was characterized using spectroscopic techniques such as FT-IR, ¹H NMR, ¹³C NMR, UV-Vis, ESI-MS, and finally, the structure was confirmed by single X-ray diffraction studies. The DFT calculation was performed to compare the gas-phase geometry of the title compound to the solid-phase structure of the title compound. Furthermore, a comparative study between theoretical UV-Vis, IR, ¹H- and ¹³C NMR spectra of the studied compound and experimental ones have been carried out. The thermal behavior and stability of the compound were analyzed by using TGA and DTA techniques which revealed that the compound is thermostable up to its melting point. Finally, the in silico docking and ADME studies are performed to investigate whether MBSP is a potential therapeutic for COVID-19.

Polymorphism of 2-(5-benzyl-6-oxo-3-phenyl-1,6-di-hydro-pyridazin-1-yl)acetic acid with two monoclinic modifications: crystal structures and Hirshfeld surface analyses

Two polymorphs of the title compound, C19H16N2O3, were obtained from ethano-lic (polymorph I) and methano-lic solutions (polymorph II), respectively. Both polymorphs crystallize in the monoclinic system with four formula units per cell and a complete mol-ecule in the asymmetric unit. The main difference between the mol-ecules of (I) and (II) is the reversed position of the hy-droxy group of the carb-oxy-lic function. All other conformational features are found to be similar in the two mol-ecules. The different orientation of the OH group results in different hydrogen-bonding schemes in the crystal structures of (I) and (II). Whereas in (I) inter-molecular O-H⋯O hydrogen bonds with the pyridazinone carbonyl O atom as acceptor generate chains with a C(7) motif extending parallel to the b-axis direction, in the crystal of (II) pairs of inversion-related O-H⋯O hydrogen bonds with an R 2 2(8) ring motif between two carb-oxy-lic functions are found. The inter-molecular inter-actions in both crystal structures were analysed using Hirshfeld surface analysis and two-dimensional fingerprint plots.

Novel compounds of hybrid structure pyridazinone–coumarin as potent inhibitors of platelet aggregation

Aim: The current limitations of antiplatelet therapy promote the search for new antithrombotic agents. Here we describe novel platelet aggregation inhibitors that combine pyridazinone and coumarin scaffolds in their structure. Results: The target compounds were synthesized in good yield from maleic anhydride, following a multistep strategy. The in vitro studies demonstrated significant antiplatelet activity in many of these compounds, with IC50 values in the low micromolar range, revealing that the activity was affected by the substitution pattern of the two selected cores. Additional studies point out their effect as inhibitors of glycoprotein (Gp) IIb/IIIa activation. Conclusion: This novel hybrid structure can be considered a good prototype for the development of potent platelet aggregation inhibitors.

Oral administration of leeches (Shuizhi): A review of the mechanisms of action on antiplatelet aggregation

ETHNOPHARMACOLOGICAL RELEVANCE

The leeches (Shuizhi) comprise approximately 680 species distributed throughout the world. As recorded, they have been used as traditional Chinese medicines since the Eastern Han Dynasty, where they were claimed for promote blood circulation and eliminate blood stasis. And have been used to prevent CVDs by exerting multiple effects when orally administered, one of which is the significant inhibition of platelet aggregation. Its ability to exert this effect has been extensively investigated in vivo and in clinical practice.

AIM OF STUDY

The aim of this review is to summarize and analyse the antiplatelet aggregation mechanisms of leeches by oral administration, support their therapeutic potential and uncover opportunities for future research.

MATERIALS AND METHODS

Relevant studies from 1980 to 2018 on leeches and platelet aggregation were collected from ancient books, pharmacopoeia, reports and theses via library and internet databases (PubMed, CNKI, Google Scholar, Web of science, SciFinder, Springer and Elsevier).

RESULTS

Leeches is a unique animal medicine, they can prevent platelet aggregation by inhibiting ADP-induced platelet aggregation, increasing PGI₂, decreasing TXA₂ and Ca²⁺, and possibly recovering endothelial cell dysfunction. Leeches also exhibit a strong ability to activate eNOS, leading to an increase in platelet-derived NO. Additionally, the pteridine compounds obtained and identified from leeches have sulfur structure similar to those of other antiplatelet aggregation agents, such as ticlopidine, clopidogrel and ticagrelor.

CONCLUSION

The present review has focused on the related antiplatelet aggregation mechanisms, dipyridine compounds and toxicological information of leeches. According to the reported data, leeches have emerged as a good source of natural medicine for the treatment of antiplatelet aggregation agents and also make educated guesses for material basis of effects on antiplatelet aggregation. This review can help provide new insights for further studies in association with the development of effective antiplatelet aggregation drugs from natural medicines, especially leeches.

A new pyridazinone exhibits potent cytotoxicity on human cancer cells via apoptosis and poly-ubiquitinated protein accumulation

In the last 15 years, pyridazinone derivatives have acquired extensive attention due to their widespread biological activities and pharmacological applications. Pyridazinones are well known for their anti-microbial, anti-viral, anti-inflammatory, anti-cancer, and cardiovascular activities, among others. In this study, we evaluated the anti-cancer activity of a new pyridazinone derivative and propose it as a potential anti-neoplastic agent in acute promyelocytic leukemia cells. Pyr-1 cytotoxicity was assessed on several human cancer and two non-cancerous cell lines by the DNS assay. Pyr-1 demonstrated potent cytotoxicity against 22 human cancer cell lines, exhibiting the most favorable selective cytotoxicity on leukemia (CEM and HL-60), breast (MDA-MB-231 and MDA-MB-468), and lung (A-549) cancer cell lines, when compared with non-cancerous breast epithelial MCF-10A cells. Analyses of apoptosis/necrosis pathways, reactive oxygen species (ROS) production, mitochondria health, caspase-3 activation, and cell cycle profile were performed via flow cytometry. Both hmox-1 RNA and protein expression levels were evaluated by quantitative real-time PCR and Western blotting assays, respectively. Pyr-1 induced apoptosis in acute promyelocytic leukemia cells as confirmed by phosphatidylserine externalization, mitochondrial depolarization, caspase-3 activation, DNA fragmentation, and disrupted cell cycle progression. Additionally, it was determined that Pyr-1 generates oxidative and proteotoxic stress by provoking the accumulation of ROS, resulting in the overexpression of the stress-related hmox-1 mRNA transcripts and protein and a marked increase in poly-ubiquitinated proteins. Our data demonstrate that Pyr-1 induces cell death via the intrinsic apoptosis pathway by accumulating ROS and by impairing proteasome activity.

Synthesis, biological evaluation and molecular modeling studies of phthalazin-1(2H)-one derivatives as novel cholinesterase inhibitors

A series of donepezil analogues based on phthalazin-1(2H)-one scaffold was studied as hChEIs. The biological results revealed that the structural modifications proposed significantly affected ChE inhibitory potency as well as selectivity AChE/BuChE.