Design, Synthesis, and Neuroprotective Effects of a Series of Pyrazolines against 6-Hydroxydopamine-Induced Oxidative Stress

Synthesis, In vivo, and In silico Evaluation of New Pyrazoline-Benzothiazole Conjugates as Antiepileptic Agents

New 2-(4-benzothiazol-2-yl-phenoxy)-1-(3,5-diphenyl-4,5-dihydro-pyrazol-1-yl)-ethanones (9a-o) have been designed and synthesized. All the synthesized compounds were characterized by thin layer chromatography and spectral analysis. The antiepileptic potential of the synthesized compounds has been tested by following standard animal screening models, including maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) models. The neurotoxic and antidepression effects of the synthesized compounds were checked by utilizing rotarod apparatus, and motor impairment test (by actophotometer) respectively. The study concluded that compounds 9c, 9d, 9f, 9i, 9n, and 9o possessed good antiepileptic potential compared to standard drugs like carbamazepine and phenytoin. The results of the rotarod performance test also established them without any neurotoxicity. The motor impairment test revealed that the synthesized compounds are also good antidepressants. In-silico studies have been performed for calculation of pharmacophore pattern, prediction of pharmacokinetic properties which determine the eligibility of synthesized compounds as orally administered molecules and interactions with the target proteins. The result of in-silico studies reinforced results obtained by in vivo study of the synthesized compounds and their possible mechanism of antiepileptic action i. e. via inhibiting voltage-gated sodium channels (VGSCs) and gamma-aminobutyric acid-A receptor.

EGFR-Targeted Pentacyclic Triterpene Analogues for Glioma Therapy

Glioma, particularly its most malignant form, glioblastoma multiforme (GBM), is the most common and aggressive malignant central nervous system tumor. The drawbacks of the current chemotherapy for GBM have aroused curiosity in the search for targeted therapies. Aberrantly overexpressed epidermal growth factor receptor (EGFR) in GBM results in poor prognosis, low survival rates, poor responses to therapy and recurrence, and therefore EGFR-targeted therapy stands out as a promising approach for the treatment of gliomas. In this context, a series of pentacyclic triterpene analogues were subjected to in vitro and in silico assays, which were conducted to assess their potency as EGFR-targeted anti-glioma agents. In particular, compound 10 was the most potent anti-glioma agent with an IC₅₀ value of 5.82 µM towards U251 human glioblastoma cells. Taking into account its low cytotoxicity to peripheral blood mononuclear cells (PBMCs), compound 10 exerts selective antitumor action towards Jurkat human leukemic T-cells. This compound also induced apoptosis and inhibited EGFR with an IC₅₀ value of 9.43 µM compared to erlotinib (IC₅₀ = 0.06 µM). Based on in vitro and in silico data, compound 10 stands out as a potential orally bioavailable EGFR-targeted anti-glioma agent endowed with the ability to cross the blood–brain barrier (BBB).

Isobornylchalcones as Scaffold for the Synthesis of Diarylpyrazolines with Antioxidant Activity

The pyrazoline ring is defined as a "privileged structure" in medicinal chemistry. A variety of pharmacological properties of pyrazolines is associated with the nature and position of various substituents, which is especially evident in diarylpyrazolines. Compounds with a chalcone fragment show a wide range of biological properties as well as high reactivity which is primarily due to the presence of an α, β-unsaturated carbonyl system. At the same time, bicyclic monoterpenoids deserve special attention as a source of a key structural block or as one of the pharmacophore components of biologically active molecules. A series of new diarylpyrazoline derivatives based on isobornylchalcones with different substitutes (MeO, Hal, NO2, N(Me)2) was synthesized. Antioxidant properties of the obtained compounds were comparatively evaluated using in vitro model Fe2+/ascorbate-initiated lipid peroxidation in the substrate containing brain lipids of laboratory mice. It was demonstrated that the combination of the electron-donating group in the para-position of ring B and OH-group in the ring A in the structure of chalcone fragment provides significant antioxidant activity of synthesized diarylpyrazoline derivatives.

Recent advancements in the development of bioactive pyrazoline derivatives

Pyrazolines remain privileged heterocycles in drug discovery. 2-Pyrazoline scaffold has been proven as a ubiquitous motif which is present in a number of pharmacologically important drug molecules such as antipyrine, ramifenazone, ibipinabant, axitinib etc. They have been widely explored by the scientific community and are reported to possess wide spectrum of biological activities. For combating unprecedented diseases and worldwide increasing drug resistance, 2-pyrazoline has been tackled as a fascinating pharmacophore to generate new molecules with improved potency and lesser toxicity along with desired pharmacokinetic profile. This review aims to summarizes various recent advancements in the medicinal chemistry of pyrazoline based compounds with the following objectives: (1) To represent inclusive data on pyrazoline based marketed drugs as well as therapeutic candidates undergoing preclinical and clinical developments; (2) To discuss recent advances in the medicinal chemistry of pyrazoline derivatives with their numerous biological significances for the eradication of various diseases; (3) Summarizes structure-activity relationships (SAR) including in silico and mechanistic studies to afford ideas for the design and development of novel compounds with desired therapeutic implications.

Synthesis, In vitro and In silico Evaluation of a Series of Pyrazolines as New Anticholinesterase Agents

Background:

Pyrazolines, electron-rich nitrogen carriers, are of great importance due to their potential applications for the treatment of many diseases including inflammation, infectious diseases and neurodegenerative disorders.

Objectives:

The purpose of this work was to synthesize new pyrazoline derivatives and evaluate their anticholinesterase effects.

Methods:

1-Aryl-5-[4-(piperidin-1-yl)phenyl]-3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazoles (1-7) were synthesized via the treatment of 1-(3,4-dimethoxyphenyl)-3-[4-(piperidin-1-yl)phenyl]prop-2- en-1-one with arylhydrazine hydrochloride derivatives in acetic acid, whereas 1-aryl-5-[4- (morpholin-4-yl)phenyl]-3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazoles (8-14) were obtained by the treatment of 1-(3,4-dimethoxyphenyl)-3-[4-(morpholin-4-yl)phenyl]prop-2-en-1-one with arylhydrazine hydrochloride derivatives in acetic acid. Their inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were determined using a modification of Ellman’s spectrophotometric method. In silico docking and Absorption, Distribution, Metabolism and Excretion (ADME) studies were performed using Schrödinger’s Maestro molecular modeling package.

Results:

In general, piperidine derivatives were found to be more effective than morpholine derivatives on cholinesterases (ChEs). 1-Phenyl-5-[4-(piperidin-1-yl)phenyl]-3-(3,4-dimethoxyphenyl)- 4,5-dihydro-1H-pyrazole (1) and 1-(4-cyanophenyl)-5-[4-(piperidin-1-yl)phenyl]-3-(3,4- dimethoxyphenyl)-4,5-dihydro-1H-pyrazole (7) were identified as the most effective AChE inhibitors in this series with 40.92% and 38.98%, respectively. Compounds 1 and 7 were docked into the active site of human AChE (PDB code: 4EY7). Both the compounds were found to be capable of forming π-π stacking interactions with Trp286. Based on in silico ADME studies, these compounds are expected to have reasonable oral bioavailability.

Conclusion:

In the view of this work, the structural modification of the identified agents is going on for the generation of new anticholinesterase agents with enhanced efficacy.

Structure-activity relationship with pyrazoline-based aromatic sulfamates as carbonic anhydrase isoforms I, II, IX and XII inhibitors: Synthesis and biological evaluation

Four new series of aromatic sulfamates were synthesized and investigated for the inhibition of four human (h) isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), hCA I, II, IX, and XII. The reported derivatives, obtained by a sulfamoylation reaction of the corresponding phenolic precursors, bear 3,5-diarylpyrazoline moieties as spacers between the benzenesulfamate fragment which binds the zinc ion from the active site, and the tail of the inhibitor. Pyrazolines are biologically privileged scaffolds, endowed with versatile biological activity, such as an anti-proliferative action. The derivatives were tested for the inhibition of the cytosolic, hCA I and II (off target isoforms) and the trans-membrane, tumor-associated hCA IX and XII enzymes (anticancer drug targets). Generally, hCA I was not effectively inhibited, whereas many low nanomolar inhibitors were evidenced against hCA II (KIs in the range of 0.42-90.1 nM), IX (KIs in the range of 0.72-63.6 nM), and XII (KIs in the range of 0.88-85.2 nM). The best substitution fragments at the pyrazoline ring included for CA II a 4-sulfamic group on the 3-aryl and halogens on the 5-aryl or a methoxy group on the 3-aryl and a 4-sulfamate group on the 5-aryl; for CA IX and CA XII they included the sulfamic group on the 3- or 4-position of the 5-aryl and an electronwithdrawing group on the 4-postion of the 3-aryl ring.

An orally antitumor chalcone hybrid inhibited HepG2 cells growth and migration as the tubulin binding agent

Liver cancer is a kind of high mortality cancer due to the difficulty of early diagnosis. It is necessary to develop the anticancer agents to treat liver cancer. Here, a novel chalcone derivative was synthesized and evaluated for anticancer activity in vitro against liver cancer cell lines (HepG2, SNU-423, SMMC7221, and SNU-398). The chalcone hybrid 9 displayed the antiproliferative effect against HepG2, SNU-423, SMMC7221 and SNU-398 cells with IC₅₀ values of 0.9 μM, 2.7 μM, 6.2 μM and 4.6 μM, respectively. Cellular mechanisms showed that derivative 9 could obviously inhibit HepG2 cells growth and colony formation in a concentration-dependent manner. Analogue 9 inhibited the migration by regulating the expression levels of migration-releated markers and transcription factors (Snail and Slug). Tubulin polymerization inhibition assay illustrated that chalcone hybrid 9 might be a potent tubulin polymerization inhibitor. Importantly, compound 9 displayed the antitumor activity against liver cancer HepG2 cells in vivo with the low toxicity toward mice. Therefore, compound 9 as a novel tubulin polymerization inhibitor deserves further investigation to treat liver cancer. Graphical abstract Compound 9 displayed the antitumor activity against liver cancer HepG2 cells in vivo and low toxicity toward mice Figure: Orally antitumor chalcone hybrid 9 inhibited HepG2 cells growth and migration as the tubulin binding agent.