Pharmacological investigation of new niclosamide-based isatin hybrids as antiproliferative, antioxidant, and apoptosis inducers.

A group of Niclosamide-linked isatin hybrids (Xo, X1, and X2) was created and examined using IR, 1HNMR, 13C NMR, and mass spectrometry. These hybrids' cytotoxicity, antioxidant, cell cycle analysis, and apoptosis-inducing capabilities were identified. Using the SRB assay, their cytotoxicity against the human HCT-116, MCF-7, and HEPG-2 cancer cell lines, as well as VERO (African Green Monkey Kidney), was evaluated. Compound X1 was the most effective compound. In HCT-116 cells, compound X1 produced cell cycle arrest in the G1 phase, promoted cell death, and induced apoptosis through mitochondrial membrane potential breakdown in comparison to niclosamide and the control. Niclosamide and compound X1 reduced reactive oxygen species generation and modulated the gene expression of BAX, Bcl-2, Bcl-xL, and PAR-4 in comparison to the control. Docking modeling indicated their probable binding modalities with the XIAP BIR2 domain, which selectively binds caspase-3/7, and highlighted their structural drivers of activity for further optimization investigations. Computational in silico modeling of the new hybrids revealed that they presented acceptable physicochemical values as well as drug-like characteristics, which may introduce them as drug-like candidates. The study proved that compound X1 might be a novel candidate for the development of anticancer agents as it presents antiproliferative activity mediated by apoptosis.

Unveiling the potential of isatin-grafted phenyl-1,2,3-triazole derivatives as dual VEGFR-2/STAT-3 inhibitors: Design, synthesis and biological assessments.

The use of VEGFR-2 inhibitors as a stand-alone treatment has proven to be ineffective in clinical trials due to the robustness of cellular response loops that lead to treatment resistance when only targeting VEGFR-2. The over-activation of the signal transducer/activator of transcription 3 (STAT-3) is expected to significantly impact treatment failure and resistance to VEGFR-2 inhibitors. In this study, we propose the concept of combined inhibition of VEGFR-2 and STAT-3 to combat induced STAT-3-mediated resistance to VEGFR-2 inhibition therapy. To explore this, we synthesized new isatin-grafted phenyl-1,2,3-triazole derivatives "6a-n" and "9a-f". Screening on PANC1 and PC3 cancer cell lines revealed that compounds 6b, 6 k, 9c, and 9f exhibited sub-micromolar ranges. The most promising molecules, 6b, 6 k, 9c, and 9f, demonstrated the highest inhibition when tested as dual inhibitors on VEGFR-2 (with IC50 range 53-82 nM, respectively) and STAT-3 (with IC50 range 5.63-10.25 nM). In particular, triazole 9f showed the best results towards both targets. Inspired by these findings, we investigated whether 9f has the ability to trigger apoptosis in prostate cancer PC3 cells via the assessment of the expression levels of the apoptotic markers Caspase-8, Bcl-2, Bax, and Caspase-9. Treatment of the PC3 cells with compound 9f significantly inhibited the protein expression levels of VEGFR-2 and STAT-3 kinases compared to the control.

Identification of Novel Isatin Derivative Bearing a Nitrofuran Moiety as Potent Multi-Isoform Aldehyde Dehydrogenase Inhibitor.

Aldehyde dehydrogenases (ALDHs) are a family of enzymes that aid in detoxification and are overexpressed in several different malignancies. There is a correlation between increased expression of ALDH and a poor prognosis, stemness, and resistance to several drugs. Several ALDH inhibitors have been generated due to the crucial role that ALDH plays in cancer stem cells. All of these inhibitors, however, are either ineffective, very toxic, or have yet to be subjected to rigorous testing on their effectiveness. Although various drug-like compounds targeting ALDH have been reported in the literature, none have made it to routine use in the oncology clinic. As a result, new potent, non-toxic, bioavailable, and therapeutically effective ALDH inhibitors are still needed. In this study, we designed and synthesized potent multi-ALDH isoform inhibitors based on the isatin and indazole pharmacophore. Molecular docking studies and enzymatic tests revealed that among all of the synthesized analogs, compound 3 is the most potent inhibitor of ALDH1A1, ALDH3A1, and ALDH1A3, exhibiting 51.32%, 51.87%, and 36.65% inhibition, respectively. The ALDEFLUOR assay further revealed that compound 3 acts as an ALDH broad spectrum inhibitor at 500 nM. Compound 3 was also the most cytotoxic to cancer cells, with an IC50 in the range of 2.1 to 3.8 µM for ovarian, colon, and pancreatic cancer cells, compared to normal and embryonic kidney cells (IC50 7.1 to 8.7 µM). Mechanistically, compound 3 increased ROS activity due to potent multi-ALDH isoform inhibition, which increased apoptosis. Taken together, this study identified a potent multi-isoform ALDH inhibitor that could be further developed as a cancer therapeutic.

Recent advances in isatin-based chemosensors: A comprehensive review.

A comprehensive review presents an illuminating exploration of the vast potential of isatin, an easily accessible organic compound. This review is a valuable resource, offering a concise yet comprehensive account of the recent breakthroughs in isatin applications in medicinal chemistry, fluorescence sensing, and organic synthesis. Moreover, it dives into the exciting advancements in isatin-based chemosensors, demonstrating their remarkable ability to detect and recognize diverse cations and anions with exceptional precision. Researchers and scientists in the fields of sensing and organic chemistry will find this review indispensable for sparking innovation and developing cutting-edge technologies with significant real-world impact.

Theoretical Study of the Mechanism of the Formation of Azomethine Ylide from Isatine and Sarcosine and Its Reactivity in 1,3-Dipolar Cycloaddition Reaction with 7-Oxabenzonorbornadiene.

The reaction mechanism of tthe formation of azomethine ylides from isatins and sarcosine is addressed in the literature in a general manner. This computational study aims to explore the mechanistic steps for this reaction in detail and to assess the reactivity of formed ylide in a 1,3-dipolar cycloaddition reaction with 7-oxabenzonorbornadiene. For this purpose, density functional theory (DFT) calculations at the M06-2X(SMD,EtOH)/6-31G(d,p) level were employed. The results indicate that CO2 elimination is the rate-determining step, the activation barrier for 1,3-dipolar cycloaddition is lower, and the formed ylide will readily react with dipolarophiles. The substitution of isatine with electron-withdrawal groups slightly decreases the activation barrier for ylide formation.

Synthesis, Fluorescence, and Bioactivity of Novel Isatin Derivatives.

The isatin group is widespread in nature and is considered to be a privileged building block for drug discovery. In order to develop novel SHP1 inhibitors with fluorescent properties as tools for SHP1 biology research, this work designed and synthesized a series of isatin derivatives. The presentive compound 5a showed good inhibitory activity against SHP1PTP with IC50 of 11 ± 3 µM, displayed about 92% inhibitory rate against MV-4-11 cell proliferation at the concentration of 20 µM, exhibited suitable fluorescent properties with a long emission wavelength and a large Stokes shift, and presented blue fluorescent imaging in HeLa cells with low cytotoxicity. This study could offer chemical tool to further understand SHP1 biology and develop novel SHP1 inhibitors in therapy.

Synthesis, Characterization, Antimicrobial and In Silico Studies of Isatin Schiff Base Linked 1,2,3-Triazole Hybrids.

A new series of isatin-Schiff base linked 1,2,3-triazole hybrids has been synthesized using CuAAC approach from (E)-3-(phenylimino)-1-(prop-2-yn-1-yl)indolin-2-one derivatives in high yield (73-91 %). These synthesized derivatives were characterized using FT-IR, 1H NMR, 13C NMR, 2D-NMR and HRMS spectral techniques. The in vitro antimicrobial activity assay demonstrated that most of the tested hybrids exhibited promising activity. Compound 5 j displayed significant antibacterial efficacy against P. aeruginosa and B. subtilis with MIC value of 0.0062 µmol/mL. While, 5 j also showed better antifungal potency against A. niger with MIC value of 0.0123 µmol/mL. The docking studies of most promising compounds were performed with the well-known antibacterial and antifungal targets i. e. 1KZ1, 5TZ1. Molecular modelling investigations demonstrated that hybrids 5 h and 5 l exhibited good interactions with 1KZN and 5TZ1, with binding energies of -9.6 and -11.0 kcal/mol, respectively. Further, molecular dynamics studies of the compounds showing promising binding interactions were also carried out to study the stability of complexes of these hybrids with both the targets.

Rational Design and Synthesis of Isatin-Chalcone Hybrids Integrated with 1H-1,2,3-Triazole: Anti-Proliferative Profiling and Molecular Docking Insights.

In this study, a series of isatin-chalcone linked triazoles were synthesized using Cu-promoted Azide-Alkyne Cycloaddition (CuAAC) reaction and evaluated for their cytotoxicity against various cancer cell lines. The most potent compound displayed approximately 2.5 times greater activity compared to both reference compounds against ovarian cancer cell lines. These findings were supported by caspase-mediated apoptosis and molecular docking analyses. Docking revealed comparable VEGFR-2 affinities for 5 b and 5-FU but highlighted stronger interaction of 5 b with EGFR, evident from its lower docking score. Overall, these results signify the notable anti-proliferative potential of most synthesized hybrids, notably emphasizing the efficacy of compound 5 b in suppressing cancer cell growth.

Design, synthesis, in vitro and in silico evaluations of new isatin-triazine- aniline hybrids as potent anti- Alzheimer multi-target directed lead compounds.

Multi target directed ligands (MTDLs) are one of the promising tools for treatment of complex disease like Alzheimer's disease (AD). In this study, using rational design, we synthesized new 15 hybrids of the s-triazine, isatin and aniline derivatives as anti- AD compounds. The design was as way as that new compounds could had anti cholinesterase (ChE), antioxidant and biometal chelation ability. In vitro biological evaluation against ChE enzymes showed that these molecules were excellent inhibitors with IC50 values ranging from 0.2 nM to 734.5 nM for acetylcholinesterase (AChE), and 0.02 µM to 1.92 µM for butyrylcholinesterase (BChE). Among these compounds, 8 l with IC50 AChE = 0.7 nM, IC50 BChE = 0.09 µM and 8n with IC50 AChE = 0.2 nM, IC50 BChE = 0.03 µM were the most potent compounds. In silico studies showed that these molecules had key and effective interactions with the corresponding enzymes residues. The molecules with hydroxyl group on aniline moiety had also good antioxidant activity with EC50 values ranging from 64.2 µM to 103.6 µM. The UV-Vis spectroscopy study revealed that molecule 8n was also able to chelate biometals such as Zn2+, Cu2+and Fe2+ properly. It was concluded that these molecules could be excellent lead compounds for future studies.

Thiazolyl-isatin derivatives: Synthesis, in silico studies, in vitro biological profile against breast cancer cells, mRNA expression, P-gp modulation, and interactions of Akt2 and VIM proteins.

The literature reports that thiazole and isatin nuclei present a range of biological activities, with an emphasis on anticancer activity. Therefore, our proposal was to make a series of compounds using the molecular hybridization strategy, which has been used by our research group, producing hybrid molecules containing the thiazole and isatin nuclei. After structural planning and synthesis, the compounds were characterized and evaluated in vitro against breast cancer cell lines (T-47D, MCF-7 and MDA-MB-231) and against normal cells (PBMC). The activity profile on membrane proteins involved in chemoresistance and tumorigenic signaling proteins was also evaluated. Among the compounds tested, the compounds 4c and 4a stood out with IC50 values of 1.23 and 1.39 µM, respectively, against the MDA-MB-231 cell line. Both compounds exhibited IC50 values of 0.45 µM for the MCF-7 cell line. Compounds 4a and 4c significantly decreased P-gp mRNA expression levels in MCF-7, 4 and 2 folds respectively. Regarding the impact on tumorigenic signaling proteins, compound 4a inhibited Akt2 in MDA-MB-231 and compound 4c inhibited the mRNA expression of VIM in MCF-7.

Design, synthesis, and biological evaluation of 3-benzenesulfonamide-linked 3-hydrazinoisatin derivatives as carbonic anhydrase inhibitors.

A new series of isatin-linked benzenesulfonamide derivatives (9a-w) were synthesized using the tail approach and assayed for their inhibitory potency against four different human carbonic anhydrase (hCA) isoforms, hCA I, II, IX, and XII. Most of these synthesized compounds exhibited interesting inhibition potency against isoforms hCA I, IX, and XII in the nanomolar range and by taking the standard drug acetazolamide. The most potent compounds in the case of hCA I were 9c (435.8 nM) and 9s (956.4 nM), for hCA IX, 9a (60.5 nM), 9d (95.6 nM), 9g (92.1 nM), and 9k (75.4 nM), and for hCA XII, 9p (84.5 nM). However, these compounds showed more selectivity toward hCA IX over hCA I, II, and XII. Thus, these compounds can be further developed as potential lead molecules for the development of isoform-selective hCA IX inhibitors with further structural modifications.

One Pot Synthesis and Biological Activity Studies of New Spirooxindoles.

This article reports one-pot synthesis of ten novel spirooxindoles using 5-methyl-2-thiohydantoin, isatin derivatives, and malononitrile in good to high yields (65-90 %). The structures of the synthesized compounds were deduced by 1H-NMR, 13C NMR, FT-IR, and Mass spectral data. The antibacterial activity of the compounds was evaluated against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) based on the Kirby-Bauer method. According to the obtained data, the synthesized compounds show more activity against Gram-positive bacteria than Gram-negative bacteria. Also, the antioxidant activity of these compounds was measured using the DPPH radical scavenging test method, which showed good to excellent activity (59.65-94.03 %). Among them, the chlorinated derivatives (4 f-j) exhibited more antioxidant activity (84.85-94.03 %) than the other compounds (4 a-e) (56.65-74.4 %) and even ascorbic acid as a standard antioxidant compound (82.3 %).

A novel isatin Schiff based cerium complex: synthesis, characterization, antimicrobial activity and molecular docking studies.

In this work, a novel isatin-Schiff base L2 had been synthesized through a simple reaction between isatin and 2-amino-5-methylthio-1,3,4-thiadiazole. The produced Schiff base L2 was then subjected to a hydrothermal reaction with cerium chloride to produce the cerium (III)-Schiff base complex C2. Several spectroscopic methods, including mass spectra, FT-IR, elemental analysis, UV-vis, 13C-NMR, 1H-NMR, Thermogravimetric Analysis, HR-TEM, and FE-SEM/EDX, were used to completely characterize the produced L2 and C2. A computer simulation was performed using the MOE software program to find out the probable biological resistance of studied compounds against the proteins in some types of bacteria or fungi. To investigate the interaction between the ligand and its complex, we conducted molecular docking simulations using the molecular operating environment (MOE). The docking simulation findings revealed that the complex displayed greater efficacy and demonstrated a stronger affinity for Avr2 effector protein from the fungal plant pathogen Fusarium oxysporum (code 5OD4) than the original ligand. The antibacterial activity of the ligand and its Ce3+ complex were applied in vitro tests against different microorganism. The study showed that the complex was found to be more effective than the ligand.

A Comprehensive Review of the Diverse Spectrum Activity of 1,2,3-Triazole-linked Isatin Hybrids.

Heterocyclic compounds containing 1,2,3-triazole and isatin as core structures have emerged as promising drug candidates due to their diverse biological activities such as anti-cancer, antifungal, antimicrobial, antitumor, anti-epileptic, antiviral, and more. The presence of 1,2,3-triazoles and isatin heterocycles in these hybrids, both individually known for their medicinal significance, has increasingly piqued the interest of drug discovery researchers, as they seek to delve deeper into their extensive pharmacological potential for enhancing therapeutic efficacy. Moreover, these hybrid compounds are synthetically accessible using readily available materials. Therefore, there is a pressing need to provide a comprehensive overview of the existing knowledge in this field, offering valuable insights to readers and paving the way for the discovery of novel 1,2,3-triazole-linked isatin hybrids with therapeutic potential.

Novel mitochondrial and DNA damaging fluorescent Calix[4]arenes bearing isatin groups as aromatase inhibitors: Design, synthesis and anticancer activity.

Breast cancer causes a high rate of mortality all over the world. Therefore, the present study focuses on the anticancer activity of new lower rim-functionalized calix[4]arenes integrated with isatin and the p-position of calixarenes with 1,4-dimethylpyridinium iodine against various human cancer cells such as MCF-7 and MDA-MB-231 breast cancer cell lines, as well as the PNT1A healthy epithelial cell line. It was observed that compound 6c had the lowest values in MCF-7 (8.83 µM) and MDA-MB-231 (3.32 µM). Cell imaging and apoptotic activity studies were performed using confocal microscopy and flow cytometry, respectively. The confocal imaging studies with 6c showed that the compound easily entered the cell, and it was observed that 6c accumulated in the mitochondria. The Comet assay test was used to detect DNA damage of compounds in cells. It was found that treated cells had abnormal tail nuclei and damaged DNA structures compared with untreated cells. In vitro human aromatase enzyme inhibition profiles showed that compound 6c had a remarkable inhibitory effect on aromatase. Compound 6c displayed a significant inhibition capacity on aromatase enzyme with the IC50 value of 0.104 ± 0.004 µM. Thus, not only the anticancer activity of the new fluorescent derivatives, which are the subject of this study, but the aromatase inhibitory profiles have also been proven.

Location-agnostic site-specific protein bioconjugation via Baylis Hillman adducts.

Proteins labelled site-specifically with small molecules are valuable assets for chemical biology and drug development. The unique reactivity profile of the 1,2-aminothiol moiety of N-terminal cysteines (N-Cys) of proteins renders it highly attractive for regioselective protein labelling. Herein, we report an ultrafast Z-selective reaction between isatin-derived Baylis Hillman adducts and 1,2-aminothiols to form a bis-heterocyclic scaffold, and employ it for stable protein bioconjugation under both in vitro and live-cell conditions. We refer to our protein bioconjugation technology as Baylis Hillman orchestrated protein aminothiol labelling (BHoPAL). Furthermore, we report a lipoic acid ligase-based technology for introducing the 1,2-aminothiol moiety at any desired site within proteins, rendering BHoPAL location-agnostic (not limited to N-Cys). By using this approach in tandem with BHoPAL, we generate dually labelled protein bioconjugates appended with different labels at two distinct specific sites on a single protein molecule. Taken together, the protein bioconjugation toolkit that we disclose herein will contribute towards the generation of both mono and multi-labelled protein-small molecule bioconjugates for applications as diverse as biophysical assays, cellular imaging, and the production of therapeutic protein-drug conjugates. In addition to protein bioconjugation, the bis-heterocyclic scaffold we report herein will find applications in synthetic and medicinal chemistry.

Synthesis, biological activity evaluation and mechanism of action of novel bis-isatin derivatives as potential anti-liver cancer agents.

A series of bis-isatin conjugates with lysine linker were synthesized with the aim of probing their antiproliferative potential. All the newly synthesized derivatives (0-100 µM) were first screened against liver cancer cell lines(Huh1, H22, Huh7, Hepa1-6, HepG2, Huh6 and 97H) using CCK-8 assay. Results indicated that the derivative 4d exhibited the most potent activity against Huh1 (IC50 = 17.13 µM) and Huh7(IC50 = 8.265 µM). In vivo anti-tumor study showed that compound 4d effectively inhibited tumor growth in Huh1-induced xenograft mouse model; the anti-tumor effect of compound 4d (15 mg/kg) was comparable with sorafenib (20 mg/kg). H&E staining analysis and routine blood test and blood serum biochemistry examination was performed to confirm the safety of compound 4d in xenograft models. The mechanism of action of 4d on tumor growth inhibition was further investigated by RNA-Seq analysis, which indicates a positive regulation of autophagy signaling pathway, which was further confirmed with key biomarker expression of autophagy after 4d treatment. Our results suggest that the bis-isatin conjugate compound 4d is a promising tumor inhibitory agent for some liver cancer.

Discovery of sulfonamide-tethered isatin derivatives as novel anticancer agents and VEGFR-2 inhibitors.

In this work, new isatin-based sulphonamides (6a-i, 11a-c, 12a-c) were designed and synthesised as potential dual VEGFR-2 and carbonic anhydrase inhibitors with anticancer activities. Firstly, all target isatins were examined for in vitro antitumor action on NCI-USA panel (58 tumour cell lines). Then, the most potent derivatives were examined for the potential CA inhibitory action towards the physiologically relevant hCA isoforms I, II, and tumour-linked hCA IX isoform, in addition, the VEGFR-2 inhibitory activity was evaluated. The target sulphonamides failed to inhibit the CA isoforms that could be attributable to the steric effect of the neighbouring methoxy group, whereas they displayed potent VEGFR-2 inhibitory effect. Following that, isatins 11b and 12b were tested for their influence on the cell cycle disturbance, and towards the apoptotic potential. Finally, detailed molecular modelling analyses, including docking and molecular dynamics, were carried out to assess the binding mode and stability of target isatins.

Antiproliferative Activity, Multikinase Inhibition, Apoptosis- Inducing Effects and Molecular Docking of Novel Isatin-Purine Hybrids.

The traditional single-treatment strategy for cancer is frequently unsuccessful due to the complexity of cellular signaling. However, suppression of multiple targets is vital to defeat tumor cells. In this research, new compounds for the treatment of cancer were developed successfully as novel hybrid anticancer agents. Based on a molecular hybridization strategy, we designed hybrid agents that target multiple protein kinases to fight cancer cells. The proposed hybrid agents combined purine and isatin moieties in their structures with 4-aminobenzohydrazide and hydrazine as different linkers. Having those two moieties in one molecule enabled the capability to inhibit multiple kinases, such as human epidermal receptor (EGFR), human epidermal growth factor receptor 2 (HER2), vascular endothelial growth factor receptor 2 (VEGFR2) and cyclin-dependent kinase 2 (CDK2). Anticancer activity was evaluated by performing cytotoxicity assays, kinase inhibition assays, cell cycle analysis, and BAX, Bcl-2, Caspase 3 and Caspase 9 protein level determination assays. The results showed that the designed hybrids tackled the cancer by inhibiting both cell proliferation and metastasis. A molecular docking study was performed to predict possible binding interactions in the active site of the investigated protein kinase enzymes.

Dipolarophile-Controlled Regioselective 1,3-Dipolar Cycloaddition: A Switchable Divergent Access to Functionalized N-Fused Pyrrolidinyl Spirooxindoles.

N-fused pyrrolidinyl spirooxindole belongs to a class of privileged heterocyclic scaffolds and is prevalent in natural alkaloids and synthetic pharmaceutical molecules. To realize the switchable synthesis of divergent N-fused pyrrolidinyl spirooxindoles for further biological activity evaluation via a substrate-controlled strategy, a chemically sustainable, catalysis-free, and dipolarophile-controlled three-component 1,3-dipolar cycloaddition of isatin-derived azomethine ylides with diverse dipolarophiles is described in this work. A total of 40 functionalized N-fused pyrrolidinyl spirooxindoles were synthesized in 76-95% yields with excellent diastereoselectivities (up to >99:1 dr). The scaffolds of these products can be well-controlled by employing different 1,4-enedione derivatives as dipolarophiles in EtOH at room temperature. This study provides an efficient strategy to afford a spectrum of natural-like and potentially bioactive N-fused pyrrolidinyl spirooxindoles.