The possible protective effect of l-cysteine in a rat model of sciatic nerve ischemia-reperfusion: A possible role for NRF1 and Caspase 3; Biochemical, Histological, and Immunohistochemical study.

Organ damage brought on by ischemia is exacerbated by the reperfusion process. L-cysteine is a semi-essential amino acid that acts as a substrate for cystathionine-ß-synthase in the central nervous system. The aim of this study was to investigate the possible protective effects of L- cysteine against the structural and biochemical changes that occur in the rat sciatic nerve after ischemia reperfusion (I/R) and to address some of the underlying mechanisms of these effects. Rats were divided into 4 groups: sham, l-cysteine, I/R, and l-cysteine- I/R groups. Specimens of sciatic nerve were processed for biochemical, histological, and immunohistochemical assessment. The results showed in I/R group, a significant increase in malondialdehyde with a significant decrease in both Nuclear respiratory factor-1 (NRF1) and superoxide dismutase levels. Moreover, with histological alteration. There was a significant increase in the mean surface area fraction of anti-caspase immunopositive cells as well as a significantdecrease in mean surface area fraction of anti-CD 34 immunopositive cells. In contrast, the l-cysteine- I/R group showed amelioration of these biochemical, structural, and immunohistochemical changes. To the best of our knowledge, this is the first study showed the protective effects of l-cysteine in sciatic nerve I/R via NRF1and caspase 3 modulation as well as telocyte activation.

Benzimidazole-Based Derivatives as Apoptotic Antiproliferative Agents: Design, Synthesis, Docking, and Mechanistic Studies.

A new class of benzimidazole-based derivatives (4a-j, 5, and 6) with potential dual inhibition of EGFR and BRAFV600E has been developed. The newly synthesized compounds were submitted for testing for antiproliferative activity against the NCI-60 cell line. All newly synthesized compounds 4a-j, 5, and 6 were selected for testing against a panel of sixty cancer cell lines at a single concentration of 10 µM. Some compounds tested demonstrated remarkable antiproliferative activity against the cell lines tested. Compounds 4c, 4e, and 4g were chosen for five-dose testing against 60 human tumor cell lines. Compound 4c demonstrated strong selectivity against the leukemia subpanel, with a selectivity ratio of 5.96 at the GI50 level. The most effective in vitro anti-cancer assay derivatives (4c, 4d, 4e, 4g, and 4h) were tested for EGFR and BRAFV600E inhibition as potential targets for antiproliferative action. The results revealed that compounds 4c and 4e have significant antiproliferative activity as dual EGFR/BRAFV600E inhibitors. Compounds 4c and 4e induced apoptosis by increasing caspase-3, caspase-8, and Bax levels while decreasing the anti-apoptotic Bcl2 protein. Moreover, molecular docking studies confirmed the potential of compounds 4c and 4e to act as dual EGFR/BRAFV600E inhibitors.

Potential protective effect of 3,3'-methylenebis(1-ethyl-4-hydroxyquinolin-2(1H)-one) against bleomycin-induced lung injury in male albino rat via modulation of Nrf2 pathway: biochemical, histological, and immunohistochemical study.

Acute lung injury is a serious condition accounting for the majority of acute respiratory failure. Bleomycin (BLM) is an antibiotic that was first described as a chemotherapeutic agent. 3,3'-methylenebis(1-ethyl-4-hydroxyquinolin-2(1H)-one) was reported to have anti-inflammatory, anti-apoptotic, and anti-oxidative properties. The current work aimed to assess the possible protective effects and the mechanism of protection of 3,3'-methylenebis-(1-ethyl-4-hydroxyquinolin-2(1H)-one) on BLM-induced lung injury in addition to the effect and underlying mechanisms of nuclear factor-erythroid-related factor 2 pathway against this injury. Rats were equally divided into four groups: control group, BLM group, 1-ethyl-4-hydroxyquinolin-2(1H)-one-treated group, and BLM with 1-ethyl-4-hydroxyquinolin-2(1H)-one-treated group. At the end of the work, the blood samples were proceeded for biochemical study. Lung specimens were obtained for biochemical, histological, and immunohistochemical study. The results exhibited a significant increase in both malondialdehyde and tumor necrotic factor-α with a significant decrease in glutathione, superoxide dismutase, IL 10, surfactant protein A, and nuclear factor erythroid 2-related factor 2 in BLM group. The lung histological results showed various morphological changes in the form of disturbed architecture, inflammatory cell infiltration, and intraluminal debris. This group also displayed a significant increase in the mean surface area fraction of anti-cleaved caspase 3, while group IV exhibited amelioration in the previously mentioned parameters and histological alternations that were induced by BLM. It could be concluded that 3,3'-methylenebis(1-ethyl-4-hydroxyquinolin-2(1H)-one) has anti-oxidative, anti-inflammatory, and anti-apoptotic protective effects against BLM-induced lung injury.

Metal complexes of thiosemicarbazones derived by 2-quinolones with Cu(I), Cu(II) and Ni(II); Identification by NMR, IR, ESI mass spectra and in silico approach as potential tools against SARS-CoV-2.

Substituted thiosemicarbazones derived by 2-quinolone were synthesized to investigate their complexation capability towards Cu(I), Cu(II) and Ni(II) salts. The structure of the complexes was established by ESI, IR and NMR spectra in addition to elemental analyses. Monodetate Cu(I) quinoloyl-substituted ligands were observed, whereas Ni(II) and Cu(II) formed bidentate-thiosemicarbazone derived by 2-quinolones. Subsequently, molecular docking was used to evaluate each analog's binding affinity as well as the inhibition constant (ki) to RdRp complex of SARS-CoV-2. Docking results supported the ability of the tested complexes that potentially inhibit the RdRp of SARSCov-2 show binding energy higher than their corresponding ligands. Additionally, ADMET prediction revealed that some compounds stratify to Lipinski's rule, indicating a good oral absorption, high bioavailability good permeability, and transport via biological membranes. Therefore, these metals-based complexes are suggested to be potentially good candidates as anti-covid agents.

Synthesis, Characterization, and In Vivo Study of Some Novel 3,4,5-Trimethoxybenzylidene-hydrazinecarbothioamides and Thiadiazoles as Anti-Apoptotic Caspase-3 Inhibitors.

The present study aims to discover novel derivatives as antiapoptotic agents and their protective effects against renal ischemia/reperfusion. Therefore, a series of new thiadiazole analogues 2a-g was designed and synthesized through cyclization of the corresponding opened hydrazinecarbothioamides 1a-g, followed by confirmation of the structure via spectroscopic tools (NMR, IR and mass spectra) and elemental analyses. The antiapoptotic activity showed alongside decreasing of tissue damage induced by I/R in the kidneys of rats using N-acetylcysteine (NAC) as an antiapoptotic reference. Most of the cyclized thiadiazoles are better antiapoptotic agents than their corresponding opened precursors. Particularly, compounds 2c and 2g were the most active antiapoptotic compounds with significant biomarkers. A preliminary mechanistic study was performed through caspase-3 inhibition. Compound 2c was selected along with its corresponding opened precursor 1c. An assay of cytochrome C revealed that there is an attenuation of cytochrome C level of about 5.5-fold, which was better than 1c with a level of 4.1-fold. In caspases-3, 8 and 9 assays, compound 2c showed more potency and selectivity toward caspase-3 and 9 compared with 1c. The renal histopathological investigation indicated normal renal tissue for most of the compounds, especially 2c and 2g, relative to the control. Finally, a molecular docking study was conducted at the caspase-3 active site to suggest possible binding modes.

Design, synthesis, mechanistic studies and in silico ADME predictions of benzimidazole derivatives as novel antifungal agents.

Herein, novel three series of benzimidazole scaffold bearing hydrazone, 1,2,4-triazole and 1,3,4-oxadiazole moieties 1-3, 4a-j, 6a-c and 7 derivatives were designed, synthesized and evaluated for their antimicrobial activity. The structures of the prepared compounds were assigned using different spectroscopic techniques such as IR, 1H NMR, 13C NMR and elemental analyses. Compounds 3, 4a, 4e and 4f exhibited remarkable antifungal activity against C. albicans and C. neoformans var. grubii with MIC values ranging from 4 to 16 µg/mL. Furthermore, they were not cytotoxic against red blood cells and human embryonic kidney cells at concentration up to 32 µg/mL. The study was expanded to forecast the mechanism of action of the prepared compounds and determine sterol quantitation method (SQM) by spectrophotometric assay. On the other hand, compound 4e showed the highest inhibitory activity against lanosterol 14α-demethylase (CYP51) with IC50 value = 0.19 µg/mL compared to fluconazole as reference IC50 value = 0.62 µg/mL. Also, compounds 4d and 4f exhibited mild to moderate antibacterial activity. Moreover, molecular docking of the active target compound 4e in active site of lanosterol 14α-demethylase (CYP51) revealed that docking scores and binding mode are comparable to that of co-crystallized ligand confirming their antifungal activity. In silico ADME prediction investigations also forecasting the drug-like characters of these compounds.

Tubulin inhibitors: Discovery of a new scaffold targeting extra-binding residues within the colchicine site through anchoring substituents properly adapted to their pocket by a semi-flexible linker.

Bis-hydrazides 13a-h were designed and synthesized as potential tubulin inhibitors selectively targeting the colchicine site between α- and ß-tubulin subunits. The newly designed ring-B substituents were assisted at their ends by 'anchor groups' which are expected to exert binding interaction(s) with new additional amino acid residues in the colchicine site (beyond those amino acids previously reported to interact with reference inhibitors as CA-4 and colchicine). Conformational flexibility of bis-hydrazide linker assisted these 'extra-binding' properties through reliving ligands' strains in the final ligand-receptor complexes. Compound 13f displayed the most promising computational and biological study results in the series: MM/GBSA binding energy of -62.362 kcal/mol (extra-binding to Arg α:221, Thr ß:353 & Lys ß:254); 34% NCI-H522 cells' death (at 10 µM), IC50 = 0.073 µM (MTT assay); significant cell cycle arrest at G2/M phase; 11.6% preG1 apoptosis induction and 83.1% in vitro tubulin inhibition (at concentration = IC50). Future researchers in bis-hydrazide tubulin inhibitors are advised to consider the 2-chloro-N-(4-substituted-phenyl)acetamide derivatives as compound 13f due to extra-binding properties of their ring B.

New quinoline-2-one/pyrazole derivatives; design, synthesis, molecular docking, anti-apoptotic evaluation, and caspase-3 inhibition assay.

We report the synthesis of new quinoline-2-one/pyrazole hybrids and their antiapoptotic activity. This effect was studied in sight of decreasing tissue damage induced by I/R in colon of rats using N-acetylcysteine (NAC) as anti-apoptotic reference. Compounds 6a, 6c and 6f showed significant improvement for oxidative stress parameters MDA, SOD, GSH and NOx in comparison with model group and greater than the reference NAC (N-acetylcysteine), whereas compounds 6d and 6e exhibited weaker antioxidant activity when compared with the reference NAC. Moreover, compounds 6a, 6c and 6f showed significant decrease in inflammatory mediators TNFα and CRB greater than NAC when compared to the model group especially compound 6c whose found CRB conc 1.90 (mg/dL) in comparison to NAC of conc 2.13 mg/dL. Additionally, colonic histopathological investigation was performed to all targeted compounds that indicates H&E sections of compounds 6a and 6f revealed apparent normal colonic cells while compound 6e showed dilated blood vessels with more apoptotic cells if compared with NAC. Caspase-3 inhibition assay revealed that compounds 6a, 6b and 6d weaken caspase-3 expression to an extent higher than NAC (1.063, 0.430, 0.731 and 1.115, respectively). Docking studies with caspase-3 revealed that most of the tested compounds showed good binding with the enzyme especially for compound 6d make several interactions better than that of the reference NAC.

Design, synthesis and molecular docking of new N-4-piperazinyl ciprofloxacin-triazole hybrids with potential antimicrobial activity.

New N-4-piperazinyl ciprofloxacin-triazole hybrids 6a-o were prepared and characterized. The in vitro antimycobacterial activity revealed that compound 6a experienced promising antimycobacterial activity against Mycobactrium smegmatis compared with the reference isoniazide (INH). Additionally, compound 6a exhibited broad spectrum antibacterial activity against all the tested strains either Gram-positive or Gram-negative bacteria compared with the reference ciprofloxacin. Also, compounds 6g and 6i displayed considerable antifungal activity compared with the reference ketoconazole. DNA cleavage assay of the highly active compounds 6c and 6h showed a good correlation between the Mycobactrium cleaved DNA gyrase assay and their in vitro antimycobactrial activity. Moreover, molecular modeling studies were done for the designed ciprofloxacin derivatives to predict their binding modes towards Topoisomerase II enzyme (PDB: 5bs8).

Design, synthesis, and DNA interaction studies of furo-imidazo[3.3.3]propellane derivatives: Potential anticancer agents.

A large number of natural products containing the propellane scaffold have been reported to exhibit cytotoxicity against several cancers; however, their mechanism of action is still unknown. Anticancer drugs targeting DNA are mainly composed of small planar molecule/s that can interact with the DNA helix, causing DNA malfunction and cell death. The aim of this study was to design and synthesize propellane derivatives that can act as DNA intercalators and/or groove binders. The unique structure of the propellane derivatives and their ability to display planar ligands with numerous possible geometries, renders them potential starting points to design new drugs targeting DNA in cancer cells. New substituted furo-imidazo[3.3.3]propellanes were synthesized via the reaction of substituted alkenylidene-hydrazinecarbothioamides with 2-(1,3-dioxo-2,3-dihydro-1H-2-ylidene)propanedinitrile in tetrahydrofuran at room temperature. The structures of the products were confirmed by a combination of elemental analysis, NMR, ESI-MS, IR and single crystal X-ray analysis. Interestingly, 5c, 5d and 5f showed an ability to interact with Calf Thymus DNA (CT-DNA). Their DNA-binding mode was investigated using a combination of absorption spectroscopy, DNA melting, viscosity, CD spectroscopy measurements, as well as competitive binding studies with several dyes. Their cytotoxicity was evaluated against the NCI-60 panel of cancer cell lines. 5c, 5d and 5f exhibited similar anti-proliferative activity against the A549 non-small cell lung cancer (NSCLC) cell line. Further mechanistic studies revealed their ability to induce DNA damage in the A549 cell line, as well as apoptosis, evidenced by elevated Annexin V expression, enhanced caspase 3/7 activation and PARP cleavage. In this study, we present the potential for designing novel propellanes to provoke cytotoxic activity, likely through DNA binding-induced DNA damage and apoptosis.

Current Trends and Future Directions of Fluoroquinolones.

Fluoroquinolones represent an interesting synthetic class of antimicrobial agents with broad spectrum and potent activity. Since the discovery of nalidixic acid, the prototype of quinolones, several structural modifications to the quinolone nucleus have been carried out for improvement of potency, spectrum of activity, and to understand their structure activity relationship (SAR). The C-7 substituent was reported to have a major impact on the activity. Accordingly, Substitution at C-7 or its N-4-piperazinyl moiety was found to affect potency, bioavailability, and physicochemical properties. Also, it can increase the affinity towards mammalian topoisomerases that may shift quinolones from antibacterial to anticancer candidates. Moreover, the presence of DNA topoisomerases in both eukaryotic and prokaryotic cells makes them excellent targets for chemotherapeutic intervention in antibacterial and anticancer therapies. Based on this concept, several fluoroquionolones derivatives have been synthesized and biologically evaluated as antibacterial, antituberculosis, antiproliferative, antiviral and antifungal agents. This review is an attempt to focus on the therapeutic prospects of fluoroquinolones with an updated account on their atypical applications such as antitubercular and anticancer activities.

Design, synthesis, molecular docking, anti-Proteus mirabilis and urease inhibition of new fluoroquinolone carboxylic acid derivatives.

New hydroxamic acid, hydrazide and amide derivatives of ciprofloxacin in addition to their analogues of levofloxacin were prepared and identified by different spectroscopic techniques. Some of the prepared compounds revealed good activity against the urease splitting bacteria, Proteus mirabilis. The urease inhibitory activity was investigated using indophenol method. Most of the tested compounds showed better activity than the reference acetohydroxamic acid (AHA). The ciprofloxacin hydrazide derivative 3a and levofloxacin hydroxamic acid 7 experienced the highest activity (IC50=1.22µM and 2.20µM, respectively). Molecular docking study revealed high spontaneous binding ability of the tested compounds to the active site of urease.

New antiproliferative 7-(4-(N-substituted carbamoylmethyl)piperazin-1-yl) derivatives of ciprofloxacin induce cell cycle arrest at G2/M phase.

New N-4-piperazinyl derivatives of ciprofloxacin 2a-g were prepared and tested for their cytotoxic activity. The primary in vitro one dose anticancer assay experienced promising cytotoxic activity against different cancer cell lines especially non-small cell lung cancer. Independently, compounds 2b, 2d, 2f and 2g showed anticancer activity against human non-small cell lung cancer A549 cells (IC50=14.8, 24.8, 23.6 and 20.7µM, respectively) compared to the parent ciprofloxacin (IC50 >100µM) and doxorubicin as a positive control (IC50=1µM). The flow cytometric analysis for 2b showed dose dependent G2/M arrest in A549 cells. Also, 2b increased the expression of p53 and p21 and decreased the expression of cyclin B1 and Cdc2 proteins in A549 cells without any effect on the same proteins expression in WI-38 cells. Specific inhibition of p53 by pifithrin-α reversed the G2/M phase arrest induced by the 2b compound, suggesting contribution of p53 to increase. Taken together, 2b induced G2/M phase arrest via p53/p21 dependent pathway. The results indicate that 2b can be used as a lead compound for further development of new derivatives against non-small cell lung cancer.