Synthesis, Cytotoxicity and Anti-Proliferative Activity Against AGS Cells of New 3(2H)-Pyridazinone Derivatives Endowed with a Piperazinyl Linker.

Novel twenty-three 3(2H)-pyridazinone derivatives were designed and synthesized based on the chemical requirements related to the anti-proliferative effects previously demonstrated within this scaffold. The introduction of a piperazinyl linker between the pyridazinone nucleus and the additional (un)substituted phenyl group led to some compounds endowed with a limited cytotoxicity against human gingival fibroblasts (HGFs) and good anti-proliferative effects against gastric adenocarcinoma cells (AGS) as evaluated by MTT and LDH assays, using doxorubicin as a positive control. Successive analyses revealed that the two most promising representative compounds (12 and 22) could exert their effects by inducing oxidative stress as demonstrated by the hydrogen peroxide release and the morphological changes (cell blebbing) revealed by light microscopy analysis after the haematoxylin-eosin staining. Moreover, to further assess the apoptotic process induced by compounds 12 and 22, Bax expression was measured by flow cytometry. These findings enlarged our knowledge of the structural requirements in this scaffold to display valuable biological effects against cancerous cell lines.

Design, Synthesis, and Biological Evaluation of Pyridazinones Containing the (2-Fluorophenyl) Piperazine Moiety as Selective MAO-B Inhibitors.

Twelve pyridazinones (T1-T12) containing the (2-fluorophenyl) piperazine moiety were designed, synthesized, and evaluated for monoamine oxidase (MAO) -A and -B inhibitory activities. T6 was found to be the most potent MAO-B inhibitor with an IC50 value of 0.013 µM, followed by T3 (IC50 = 0.039 µM). Inhibitory potency for MAO-B was more enhanced by meta bromo substitution (T6) than by para bromo substitution (T7). For para substitution, inhibitory potencies for MAO-B were as follows: -Cl (T3) > -N(CH3)2 (T12) > -OCH3 (T9) > Br (T7) > F (T5) > -CH3 (T11) > -H (T1). T6 and T3 efficiently inhibited MAO-A with IC50 values of 1.57 and 4.19 µM and had the highest selectivity indices (SIs) for MAO-B (120.8 and 107.4, respectively). T3 and T6 were found to be reversible and competitive inhibitors of MAO-B with Ki values of 0.014 and 0.0071, respectively. Moreover, T6 was less toxic to healthy fibroblast cells (L929) than T3. Molecular docking simulations with MAO binding sites returned higher docking scores for T6 and T3 with MAO-B than with MAO-A. These results suggest that T3 and T6 are selective, reversible, and competitive inhibitors of MAO-B and should be considered lead candidates for the treatment of neurodegenerative disorders like Alzheimer's disease.

Synthesis and biological evaluation of new 3(2H)-pyridazinone derivatives as non-toxic anti-proliferative compounds against human colon carcinoma HCT116 cells.

Novel 3(2H)-pyridazinone derivatives were designed, synthesised in satisfactory yields and evaluated in different experimental assays to assess their preliminary toxicity in vivo and anti-proliferative effects against HCT116 cell lines in vitro. Artemia salina lethality test provided LC50 values >100 µg/mL for all compounds. Successive assays revealed that some compounds were endowed with a promising anti-proliferative effect against HCT116 cells, alone or stimulated by serotonin as a pro-inflammatory factor in order to mimick an inflamed model in vivo of cancer cell microenvironment. Moreover, the kinurenic acid level after treatment with these newly synthesised compounds was monitored as a marker of anti-proliferation in colon carcinoma models. The IC50 values obtained for the best-in-class compounds were comparable to that of daunorubicin as a reference drug. Conversely, these compounds were not able to counteract the spontaneous migration of human cancer HCT116 cell line in the wound healing paradigm.

Synthesis, molecular modelling and biological activity of some pyridazinone derivatives as selective human monoamine oxidase-B inhibitors.

BACKGROUND: Since brain neurotransmitter levels are associated with the pathology of various neurodegenerative diseases like Parkinson and Alzheimer, monoamineoxidase (MAO) plays a critical role in balancing these neurotransmitters in the brain. MAO isoforms appear as promising drug targets for the development of central nervous system agents. Pyridazinones have a broad array of biological activities. Here, six pyridazinone derivatives were synthesized and their human monoamine oxidase inhibitory activities were evaluated by molecular docking studies, in silico ADME prediction and in vitro biological screening tests. METHODS: The compounds were synthesized by the reaction of different piperazine derivatives with 3 (2H)-pyridazinone ring and MAO-inhibitory effects were investigated. Docking studies were conducted with Maestro11.8 software. RESULTS: Most of the synthesized compounds inhibited hMAO-B selectively except compound 4f. Compounds 4a-4e inhibited hMAO-B selectively and reversibly in a competitive mode. Compound 4b was found as the most potent (ki = 0.022 ± 0.001 µM) and selective (SI (Ki hMAO-A/hMAO-B) = 206.82) hMAO-B inhibitor in this series. The results of docking studies were found to be consistent with the results of the in vivo activity studies. Compounds 4a-4e were found to be non-toxic to HepG2 cells at 25 µM concentration. In silico calculations of ADME properties indicated that the compounds have good pharmacokinetic profiles. CONCLUSION: It was concluded that 4b is possibly recommended as a promising nominee for the design and development of new pyridazinones which can be used in the treatment of neurological diseases.

A Series of New Hydrazone Derivatives: Synthesis, Molecular Docking and Anticholinesterase Activity Studies.

BACKGROUND: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are known to be serine hydrolase enzymes responsible for the hydrolysis of acetylcholine (ACh), which is a significant neurotransmitter for regulation of cognition in animals. Inhibition of cholinesterases is an effective method to curb Alzheimer's disease, a progressive and fatal neurological disorder. OBJECTIVE: In this study, 30 new hydrazone derivatives were synthesized. Then we evaluated their anticholinesterase activity of compounds. We also tried to get insights into binding interactions of the synthesized compounds in the active site of both enzymes by using molecular docking approach. METHODS: The compounds were synthesized by the reaction of various substituted/nonsubstituted benzaldehydes with 6-(substitute/nonsubstituephenyl)-3(2H)-pyridazinone-2-yl propiyohydrazide. Anticholinesterase activity of the compounds was determined using Ellman's method. Molecular docking studies were done by using the ADT package version 1.5.6rc3 and showed by Maestro. RMSD values were obtained using Lamarckian Genetic Algorithm and scoring function of AutoDock 4.2 release 4.2.5.1 software. RESULTS: The activities of the compounds were compared with galantamine as cholinesterase enzyme inhibitor, where some of the compounds showed higher BChE inhibitory activity than galantamine. Compound F111 was shown to be the best BChE inhibitor effective in 50 µM dose, providing 89.43% inhibition of BChE (IC50=4.27±0.36 µM). CONCLUSION: This study supports that novel hydrazone derivates may be used for the development of new BChE inhibitory agents.

A new series of pyridazinone derivatives as cholinesterases inhibitors: Synthesis, in vitro activity and molecular modeling studies.

BACKGROUND: The pyridazinone nucleus has been incorporated into a wide variety of therapeutically interesting molecules to transform them into better drugs. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are known to be serine hydrolase enzymes responsible for the hydrolysis of acetylcholine (ACh). Inhibition of cholinesterases is an effective method to curb Alzheimer's disease. Here, we prepared 12 new 6-substituted-3(2H)-pyridazinone-2-acetyl-2-(nonsubstituted/4-substituted benzenesulfonohydrazide) derivatives and evaluated their inhibitory effects on AChE/BChE in pursuit of potent dual inhibitors for Alzheirmer's Disease. We also tried to get insights into binding interactions of the synthesized compounds in the active site of both enzymes by using molecular docking approach. METHOD: We obtained our compounds by the reaction of various substituted/nonsubstituted benzenesulfonic acid derivatives with 6-substitutedphenyl-3(2H)-pyridazinone-2-yl acetohydrazide and determined their anticholinesterase activities according to the Ellman's method. Molecular docking studies were done using Glide and the results were evaluated on Maestro (Schrödinger, LLC, New York, NY, 2019). RESULTS: The title compounds showed moderate inhibition at 100 µg/ml against both enzymes, yet with better activity against BChE. Compound VI2a emerged as a dual inhibitor with 25.02% and 51.70% inhibition against AChE and BChE, respectively. CONCLUSION: This study supports that novel pyridazinone derivates may be used for the development of new BChE inhibitory agents. It was less potent than the reference drugs, yet promising for further modifications as a lead. The ability of the compounds to adopt energetically more favourable conformations and to engage in more key interactions in the ECBChE active gorge explains their better activity profile against ECBChE.