Design, synthesis, insilco study and biological evaluation of new isatin-sulfonamide derivatives by using mono amide linker as possible as histone deacetylase inhibitors.

OBJECTIVE: Aim: To evaluate the cytotoxic activity of newly synthesized a series of novel HDAC inhibitors comprising sulfonamide as zinc binding group and Isatin derivatives as cap group joined by mono amide linker as required to act as HDAC inhibitors. PATIENTS AND METHODS: Materials and Methods: The utilization of sulfonamide as zinc binding group joined by N-alkylation reaction with ethyl-bromo hexanoate as linker group that joined by amide reaction with Isatin derivatives as cap groups which known to possess antitumor activity in the designed of new histone deacetylase inhibitors and using the docking and MTT assay to evaluate the compounds. RESULTS: Results: Four compounds have been synthesized and characterized successfully by ART-FTIR, NMR and ESI-Ms. the compounds were synthesized and characterized by successfully by ART-FTIR, NMR and ESI- Ms. Assessed for their cytotoxic activity against human colon adenocarcinoma MCF-7 (IC50, I=105.15, II=60.00, III=54.11, IV=56.57, vorinostat=28.41) and hepatoblastoma HepG2 (IC50, I=63.91, II=135.18, III=118.85, IV=51.46, vorinostat=37.50). Most of them exhibited potent HDAC inhibitory activity and significant cytotoxicity. CONCLUSION: Conclusions: The synthesized compounds (I, II, III and IV) showed cytotoxicity toward MCF-7 and HepG2 cancer cell lines and their docking analysis provided a preliminary indication that they are viable [HDAC6] candidates.

The delayed effect of rotenone on the relative content of brain isatin-binding proteins of rats with experimental parkinsonism.

Isatin (indoldione-2,3) is an endogenous biological regulator found in the brain, peripheral tissues, and biological fluids of humans and animals. Its biological activity is realized via isatin-binding proteins, many of which were identified during proteomic profiling of the brain of mice and rats. A number of these proteins are related to the development of neurodegenerative diseases. Previously, using a model of experimental Parkinsonism induced by a seven-day course of rotenone injections, we have observed behavioral disturbances, as well as changes in the profile and relative content of brain isatin-binding proteins. In this study, we have investigated behavioral responses and the relative content of brain isatin-binding proteins in rats with rotenone-induced Parkinsonism 5 days after the last administration of this neurotoxin. Despite the elimination of rotenone, animals exhibited motor and coordination impairments. Proteomic profiling of isatin-binding proteins revealed changes in the relative content of 120 proteins (the relative content of 83 proteins increased and that of 37 proteins decreased). Comparison of isatin-binding proteins characterized by the changes in the relative content observed in the brain right after the last injection of rotenone (n=16) and 5 days later (n=11) revealed only two common proteins (glyceraldehyde-3-phosphate dehydrogenase and subunit B of V-type proton ATPase). However, most of these proteins are associated with neurodegeneration, including Parkinson's and Alzheimer's diseases.

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.

Early pharmacological profiling of isatin derivatives as potent and selective cytotoxic agents.

Isatin derivatives have attracted a lot of interest for their potential in the development of new anticancer drugs. A library of 38 isatin derivatives, created through an Ugi four-component reaction, underwent an initial screening in a panel of six human solid tumor cell lines. The four most active derivatives were then selected for further testing. These compounds showed selectivity towards the non-small cell lung cancer (NSCLC) cell line SW1573, whilst NSCLC A549 cells were barely affected. The combination of phenotypic assays, including wound healing, clonogenic and continuous live cell imaging provided a deeper understanding of the compounds' mode of action. In particular, the latter demonstrated that isatin derivatives were able to induce necroptosis in SW1573 cells. The kinetics of cell death showed that necroptosis appeared after 2.5 h of exposure, which could be delayed to 7 h when co-treated with necrostatin-1. Interaction between the isatin derivatives and the KRAS G12C protein variant was discarded after in silico studies. Further studies are warranted to identify the cellular target responsible for the observed selectivity among cell lines.

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.

Identification of new anti-mycobacterial agents based on quinoline-isatin hybrids targeting enoyl acyl carrier protein reductase (InhA).

Tuberculosis (TB) is a global issue that poses a significant economic burden as a result of the ongoing emergence of drug-resistant strains. The urgent requirement for the development of novel antitubercular drugs can be addressed by targeting specific enzymes. One such enzyme, Mycobacterium tuberculosis (MTB) enoyl-acyl carrier protein (enoyl-ACP) reductase (InhA), plays a crucial role in the survival of the MTB bacterium. In this research study, a series of hybrid compounds combining quinolone and isatin were synthesized and assessed for their effectiveness against MTB, as well as their ability to inhibit the activity of the InhA enzyme in this bacterium. Among the compounds tested, 7a and 5g exhibited the most potent inhibitory activity against MTB, with minimum inhibitory concentration (MIC) values of 55 and 62.5 µg/mL, respectively. These compounds were further evaluated for their inhibitory effects on InhA and demonstrated significant activity compared to the reference drug Isoniazid (INH), with IC50 values of 0.35 ± 0.01 and 1.56 ± 0.06 µM, respectively. Molecular docking studies investigated the interactions between compounds 7a and 5g and the target enzyme, revealing hydrophobic contacts with important amino acid residues in the active site. To further confirm the stability of the complexes formed by 5g and 7a with the target enzyme, molecular dynamic simulations were employed, which demonstrated that both compounds 7a and 5g undergo minor structural changes and remain nearly stable throughout the simulated process, as assessed through RMSD, RMSF, and Rg values.

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.

Isatin-tethered halogen-containing acylhydrazone derivatives as monoamine oxidase inhibitor with neuroprotective effect.

Sixteen isatin-based hydrazone derivatives (IS1-IS16) were synthesized and assessed for their ability to inhibit monoamine oxidases (MAOs). All the molecules showed improved inhibitory MAO-B activity compared to MAO-A. Compound IS7 most potently inhibited MAO-B with an IC50 value of 0.082 µM, followed by IS13 and IS6 (IC50 = 0.104 and 0.124 µM, respectively). Compound IS15 most potently inhibited MAO-A with an IC50 value of 1.852 µM, followed by IS3 (IC50 = 2.385 µM). Compound IS6 had the highest selectivity index (SI) value of 263.80, followed by IS7 and IS13 (233.85 and 212.57, respectively). In the kinetic study, the Ki values of IS6, IS7, and IS13 for MAO-B were 0.068 ± 0.022, 0.044 ± 0.002, and 0.061 ± 0.001 µM, respectively, and that of IS15 for MAO-A was 1.004 ± 0.171 µM, and the compounds were reversible-type inhibitors. The lead compounds were central nervous system (CNS) permeable, as per parallel artificial membrane permeability assay (PAMPA) test results. The lead compounds were examined for their cytotoxicity and potential neuroprotective benefits in hazardous lipopolysaccharide (LPS)-exposed SH-SY5Y neuroblastoma cells. Pre-treatment with lead compounds enhanced anti-oxidant levels (SOD, CAT, GSH, and GPx) and decreased ROS and pro-inflammatory cytokine (IL-6, TNF-alpha, and NF-kB) production in LPS-intoxicated SH-SY5Y cells. To confirm the promising effects of the compound, molecular docking, dynamics, and MM-GBSA binding energy were used to examine the molecular basis of the IS7-MAO-B interaction. Our findings indicate that lead compounds are potential therapeutic agents to treat neurological illnesses, such as Parkinson's disease.

Formation of bis-spiropyrrolidines from isatin, secondary amines, and alkylidene Meldrum's acids.

A catalyst-free synthesis of stable bis-spiropyrrolidines from isatin, secondary amines, and alkylidene Meldrum's acids in MeCN in 75-95% yield is described. The antioxidant and antimicrobial properties of the synthesized compounds are investigated. For this purpose, the radical scavenging activities of four derivatives were studied by radical trapping of diphenylpicrylhydrazine and ferric reduction power experiments. Disk diffusion test on Gram-positive and Gram-negative bacteria was employed to investigate antibacterial activities of five derivatives.

Design and synthesis of benzo[b]thiophene-based hybrids as novel antitubercular agents against MDR/XDR Mycobacterium tuberculosis.

In an effort to support the global fight against tuberculosis (TB), which is widely recognized as the most lethal infectious disease worldwide, we present the design and synthesis of new benzo[b]thiophene-based hybrids as promising candidates for the management of multidrug-resistant (MDR)/extensively drug-resistant (XDR) Mycobacterium tuberculosis. The isatin motif was incorporated into the target hybrids as it represents a privileged scaffold in antitubercular drug discovery. Since lipophilicity plays a pivotal role in the anti-TB agents' activity, the lipophilicity of the target hybrids was manipulated via the development of two series of N-1 methyl and N-1 benzyl substituted isatins (6a-h and 9a-h, respectively). Screening of the target hybrids was first performed against drug-sensitive M. tuberculosis (ATCC 25177). The structure-activity relationship outputs highlighted that incorporation of 3-unsubstituted benzo[b]thiophene and 5-methoxy isatin moieties was favorable for the antimycobacterial activity. Thereafter, the most potent molecules (6b-h, 9c-e, and 9h) were evaluated against the resistant strains MDR-TB (ATCC 35822) as well as against XDR-TB (RCMB 2674) where they displayed promising activity. To evaluate the safety of the target hybrids, an sulforhodamine B assay was conducted to determine their possible cytotoxic effects on VERO cells.

Evaluation of N-alkyl isatins and indoles as acetylcholinesterase and butyrylcholinesterase inhibitors.

Two series of N-alkyl isatins and N-alkyl indoles varying in size of the alkyl group were synthesised and evaluated for inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among the N-alkyl isatins 4a-j, the addition of the N-alkyl group improved inhibition potency towards AChE and BChE compared to isatin. Selectivity towards inhibition of BChE was observed, and the increase in size of the N-alkyl group positively correlated to improved inhibition potency. The most potent inhibitor for BChE was 4i (IC50 = 3.77 µM, 22-fold selectivity for BChE over AChE). N-alkyl indoles 5a-j showed similar inhibition of AChE, the most potent being 5g (IC50 = 35.0 µM), but 5a-j lost activity towards BChE. This suggests an important role of the 3-oxo group on isatin for BChE inhibition, and molecular docking of 4i with human BChE indicates a key hydrogen bond between this group and Ser198 and His438 of the BChE catalytic triad.

Synthesis biological evaluation and molecular docking of isatin hybrids as anti-cancer and anti-microbial agents.

Isatin, known as 1H-indole-2,3-dione, was originally recognised as a synthetic molecule until its discovery in the fruits of the cannonball tree, Couroupita guianensis. It is naturally occurring in plants of the genus Isatis and serves as a metabolic derivative of adrenaline in humans. Isatin possesses significant pharmacological importance, and its synthetic versatility has prompted extensive interest in its derivative compounds due to their diverse biological and pharmacological properties. These derivatives represent a valuable class of heterocyclic compounds with potential applications as precursors for synthesizing numerous valuable drugs. In the pursuit of advancing our research on isatin hybrids, we investigate the utilisation of readily available hydrazonoindolin-2-one and isatin as starting materials for the synthesis of a wide range of analogues. Characterisation of the synthesized compounds was carried out through various analytical techniques. Furthermore, the obtained compounds were subjected to extensive testing to evaluate their anticancer and antimicrobial activities. Specifically, their efficacy against key proteins, namely Staphylococcus aureus protein (PDB ID: 1JIJ), Escherichia coli protein (PDB ID: 1T9U), Pseudomonas aeruginosa protein (PDB ID: 2UV0), and Acinetobacter baumannii protein (PDB ID: 4HKG), was examined through molecular docking calculations. Several molecules, such as 3, 4, 6, 16, and 19, displayed remarkable activity against the renal cancer cell line UO-31. Additionally, the results of antimicrobial activity testing revealed that compound 16 exhibited significant cytotoxicity against Candida albicans and Cryptococcus neoformans. Subsequently, ADME/T calculations were performed to gain insights into the potential effects and reactions of these molecules within human metabolism. This comprehensive study provides valuable insights into the potential pharmacological applications of isatin derivatives and underscores their significance in drug development.

Isatin-indoloquinoxaline click adducts with a potential to overcome platinum-based drug-resistance in ovarian cancer.

Herein, a series of isatin tethered indolo[2,3-b]quinoxaline hybrids was synthesized by considering the pharmacophoric features of known DNA intercalators and topoisomerase II inhibitors. The anti-proliferative properties of the synthesized compounds were evaluated against ovarian cancer cell lines (SKOV-3 and Hey A8). Four of the compounds exhibited promising anti-proliferative activities, with one of them being 10-fold more potent than cisplatin against drug-resistant Hey A8 cells. Further investigations were carried out to determine the DNA intercalating affinities of the most active compounds as potential mechanisms for their anti-proliferative activities. ADMET in silico studies were performed to assess the physicochemical, pharmacokinetics, and toxicity parameters of active compounds. This study, to the best of our knowledge, is the first report on the potential of isatin-indoloquinoxaline hybrids as structural blueprints for the development of new DNA intercalators. Additionally, it explores their potential to circumvent platinum-based resistance in ovarian cancer.

Neuroprotective effects of isatin and afobazole in rats with rotenone-induced Parkinsonism are accompanied by increased brain levels of Triton X-100 soluble alpha-synuclein.

Effects of the endogenous neuroprotector isatin and the pharmacological drug afobazole (exhibiting neuroprotective properties) on behavioral reactions and quantitative changes in the brain proteomic profile have been investigated in rats with experimental rotenone Parkinsonism. A single dose of isatin (100 mg/kg subcutaneously on the last day of a 7-day course of rotenone administration) improved the motor activity of rats with rotenone-induced Parkinsonism in the open field test (horizontal movements) and the rotating rod test. Afobazole (10 mg/kg intraperitoneally, daily during the 7-day course of rotenone administration) reduced the manifestations of rigidity and postural instability. Proteomic analysis, performed using brain samples obtained the day after the last administration of rotenone and neuroprotectors, revealed similar quantitative changes in the brain of rats with rotenone Parkinsonism. An increase in the relative content of 65 proteins and a decrease in the relative content of 21 proteins were detected. The most pronounced changes - an almost ninety-fold increase in the alpha-synuclein content - were found in the brains of rats treated with isatin. In animals of the experimental groups treated with "Rotenone + Isatin", as well as "Rotenone + Afobazole", the increase in the relative content of this protein in the brain was almost 60 and 50 times higher than the control values. Taking into consideration the known data on the physiological role of alpha-synuclein, an increase in the content of this protein in the brain upon administration of neuroprotectors to animals with rotenone Parkinsonism may represent a compensatory reaction, at least in the early stages of this disease and the beginning of its treatment.

Anticancer and Antiphytopathogenic Activity of Fluorinated Isatins and Their Water-Soluble Hydrazone Derivatives.

A series of new fluorinated 1-benzylisatins was synthesized in high yields via a simple one-pot procedure in order to explore the possible effect of ortho-fluoro (3a), chloro (3b), or bis-fluoro (3d) substitution on the biological activity of this pharmacophore. Furthermore, the new isatins could be converted into water-soluble isatin-3-hydrazones using their acid-catalyzed reaction with Girard's reagent P and its dimethyl analog. The cytotoxic action of these substances is associated with the induction of apoptosis caused by mitochondrial membrane dissipation and stimulated reactive oxygen species production in tumor cells. In addition, compounds 3a and 3b exhibit platelet antiaggregation activity at the level of acetylsalicylic acid, and the whole series of fluorine-containing isatins does not adversely affect the hemostasis system as a whole. Among the new water-soluble pyridinium isatin-3-acylhydrazones, compounds 7c and 5c,e exhibit the highest antagonistic effect against phytopathogens of bacterial and fungal origin and can be considered useful leads for combating plant diseases.

The anti-breast cancer potential of indole/isatin hybrids.

Breast cancer (BC) is one of the most prevalent malignancies and the major contributor to cancer mortality in women globally, with a high degree of heterogeneity and a dismal prognosis. As drug resistance is responsible for most BC fatalities and advanced BC is currently considered incurable, finding innovative anti-BC chemotherapeutics is urgently required. Indole and its analog isatin (indole-1H-2,3-dione) are prominent pharmacophores in the development of novel medications, and their derivatives exhibit strong anticancer activities, also against BC. In particular, indole/isatin hybrids exhibit significant potency against BC including multidrug-resistant forms and excellent selectivity by influencing a variety of biological targets associated with the disease, supplying helpful building blocks for the identification of potential new BC treatment options. This review includes articles from 2020 to the present and provides insights into the in vitro and in vivo anti-BC potential, molecular mechanisms, and structure-activity relationships (SARs) of indole/isatin hybrids that may be helpful in the development of innovative anti-BC chemotherapeutics.

Novel 7-Deazapurine Incorporating Isatin Hybrid Compounds as Protein Kinase Inhibitors: Design, Synthesis, In Silico Studies, and Antiproliferative Evaluation.

Cancer is a multifactorial disorder with extremely complex genetics and progression. The major challenge in cancer therapy is the development of cancer resistance and relapse. Conventional anticancer drugs directly target the DNA of the cell, while modern chemotherapeutic drugs include molecular-targeted therapy, such as targeting the abnormal cell signaling inside the cancer cells. Targeted chemotherapy is effective in several malignancies; however, the success has always been limited by drug resistance and/or side effects. Anticancer with multi-targeted actions simultaneously modulates multiple cancer cell signaling pathways and, therefore, may ease the chance of effective anticancer drug development. In this research, a series of 7-deazapurine incorporating isatin hybrid compounds was designed and successfully synthesized. Among those hybrids, compound 5 demonstrated a very potent cytotoxic effect compared to the reference anticancer drug against four cancer cell lines. Likewise, compound 5 inhibited the activity of four protein kinase enzymes in nanomolar ranges. Further analysis of the biological evaluation of compound 5 revealed the capability of compound 5 to arrest cell cycle progression and induce programmed cell death. Moreover, molecular simulation studies were performed to investigate the possible types of interactions between compound 5 and the investigated protein kinases. Finally, taking into consideration all the abovementioned findings, compound 5 could be a good candidate for further investigations.

Design and synthesis of isatin derivatives as effective SARS-CoV-2 3CL protease inhibitors.

SARS-CoV-2 chymotrypsin-like cysteine protease (3CLpro ) is one of the most widely developed drug targets for COVID-19. This study aimed to design and synthesize isatin derivatives to target SARS-CoV-2 3CLpro in a covalent binding manner. Through the process, a potent 3CLpro inhibitor (5g) was discovered with an IC50 value of 0.43 ± 0.17 µM. To understand the binding affinity and specificity of 5g as a candidate inhibitor of SARS-CoV-2 3CLpro , several assays were conducted, including FRET enzyme activity assays, thermodynamic-based and kinetic-based validation of inhibitor-target interactions, and cell-based FlipGFP assays. The interaction mechanism between 3CLpro -5g was characterized by docking. Overall, these findings suggest that 5g is a new potent SARS-CoV-2 3CLpro inhibitor for the treatment of COVID-19.

Design, Synthesis, Molecular Docking, and Biological Evaluation of Isatin-Based Fused Heterocycles As Epidermal Growth Factor Receptor Inhibitors.

A series of isatin-based fused heterocycles were designed, synthesized, and evaluated for anticancer activity against four cancer cell lines: MCF-7, MDA-MB-231, A549, and HL-60. Among them, Q3 and T4 were found to be potent anticancer agents. Furthermore, two compounds Q3 and T4 were selected for epidermal growth factor receptor (EGFR) inhibitory activity. Two compounds Q3 and T4 were found to be most potent EGFR inhibitors with IC50 of 0.22 ± 0.10 and 0.19 ± 0.07 µM. The EGFR inhibitory activity of standard drug erlotinib was 0.08 ± 0.02 µM. Structural Activity Relationship studies showed that electronegative atoms were necessary for EGFR inhibitory potential. Finally, molecular docking studies were carried out to check the binding pattern of synthesized derivatives with the adenosine triphosphate (ATP) binding site of EGFR and results revealed that compounds Q3 (-9.2 kcal/mol) and T4 (-8.9 kcal/mol) exhibited better binding affinity than reference drug erlotinib (-7.3 kcal/mol).

Evaluation of Anti-Neuroinflammatory Activity of Isatin Derivatives in Activated Microglia.

Neuroinflammation plays a crucial role in the progression of Alzheimer's disease and other neurodegenerative disorders. Overactivated microglia cause neurotoxicity and prolong the inflammatory response in many neuropathologies. In this study, we have synthesised a series of isatin derivatives to evaluate their anti-neuroinflammatory potential using lipopolysaccharide activated microglia as a cell model. We explored four different substitutions of the isatin moiety by testing their anti-neuroinflammatory activity on BV2 microglia cells. Based on the low cytotoxicity and the activity in reducing the release of nitric oxide, pro-inflammatory interleukin 6 and tumour necrosis factor α by microglial cells, the N1-alkylated compound 10 and the chlorinated 20 showed the best results at 25 µM. Taken together, the data suggest that 10 and 20 are promising lead compounds for developing new neuroprotective agents.