Alkenyl oxindole is a novel PROTAC moiety that recruits the CRL4DCAF11 E3 ubiquitin ligase complex for targeted protein degradation.

Alkenyl oxindoles have been characterized as autophagosome-tethering compounds (ATTECs), which can target mutant huntingtin protein (mHTT) for lysosomal degradation. In order to expand the application of alkenyl oxindoles for targeted protein degradation, we designed and synthesized a series of heterobifunctional compounds by conjugating different alkenyl oxindoles with bromodomain-containing protein 4 (BRD4) inhibitor JQ1. Through structure-activity relationship study, we successfully developed JQ1-alkenyl oxindole conjugates that potently degrade BRD4. Unexpectedly, we found that these molecules degrade BRD4 through the ubiquitin-proteasome system, rather than the autophagy-lysosomal pathway. Using pooled CRISPR interference (CRISPRi) screening, we revealed that JQ1-alkenyl oxindole conjugates recruit the E3 ubiquitin ligase complex CRL4DCAF11 for substrate degradation. Furthermore, we validated the most potent heterobifunctional molecule HL435 as a promising drug-like lead compound to exert antitumor activity both in vitro and in a mouse xenograft tumor model. Our research provides new employable proteolysis targeting chimera (PROTAC) moieties for targeted protein degradation, providing new possibilities for drug discovery.

Pyrano[2,3-c]pyrazole fused spirooxindole-linked 1,2,3-triazoles as antioxidant agents: Exploring their utility in the development of antidiabetic drugs via inhibition of α-amylase and DPP4 activity.

Environment-benign, multicomponent synthetic methodologies are vital in modern pharmaceutical research and facilitates multi-targeted drug development via synergistic approach. Herein, we reported green and efficient synthesis of pyrano[2,3-c]pyrazole fused spirooxindole linked 1,2,3-triazoles using a tea waste supported copper catalyst (TWCu). The synthetic approach involves a one-pot, five-component reaction using N-propargylated isatin, hydrazine hydrate, ethyl acetoacetate, malononitrile/ethyl cyanoacetate and aryl azides as model substrates. Mechanistically, the reaction was found to proceed via in situ pyrazolone formation followed by Knoevenagel condensation, azide alkyne cycloaddition and Michael's addition reactions. The molecules were developed using structure-based drug design. The primary goal is to identifying anti-oxidant molecules with potential ability to modulate α-amylase and DPP4 (dipeptidyl-peptidase 4) activity. The anti-oxidant analysis, as determined via DPPH, suggested that the synthesized compounds, A6 and A10 possessed excellent anti-oxidant potential compared to butylated hydroxytoluene (BHT). In contrast, compounds A3, A5, A8, A9, A13, A15, and A18 were found to possess comparable anti-oxidant potential. Among these, A3 and A13 possessed potential α-amylase inhibitory activity compared to the acarbose, and A3 further emerged as dual inhibitors of both DPP4 and α-amylase with anti-oxidant potential. The relationship of functionalities on their anti-oxidant and enzymatic inhibition was explored in context to their SAR that was further corroborated using in silico techniques and enzyme kinetics.

Discovery and optimization of narrow spectrum inhibitors of Tousled like kinase 2 (TLK2) using quantitative structure activity relationships.

The oxindole scaffold has been the center of several kinase drug discovery programs, some of which have led to approved medicines. A series of two oxindole matched pairs from the literature were identified where TLK2 was potently inhibited as an off-target kinase. The oxindole has long been considered a promiscuous kinase inhibitor template, but across these four specific literature oxindoles TLK2 activity was consistent, while the kinome profile was radically different ranging from narrow to broad spectrum kinome coverage. We synthesized a large series of analogues, utilizing quantitative structure-activity relationship (QSAR) analysis, water mapping of the kinase ATP binding sites, kinome profiling, and small-molecule x-ray structural analysis to optimize TLK2 inhibition and kinome selectivity. This resulted in the identification of several narrow spectrum, sub-family selective, chemical tool compounds including 128 (UNC-CA2-103) that could enable elucidation of TLK2 biology.

A water mediated multicomponent reaction for the synthesis of novel spirooxindole derivatives and their antifungal activity.

A water mediated three-component reaction of isatin, 4-aminocoumarin, and 1,3-cyclodicarbonyl compounds is reported for the synthesis of spiro[chromeno[4,3-b]cyclopenta[e]pyridine-7,3'-indoline]trione and the spiro[chromeno[4,3-b]quinoline 7,3'-indoline]trione. Up to 27 different spirooxindole derivatives were synthesized by this method. The bioactivity of these spirooxindole derivatives was evaluated and they were found to show antifungal activity against Cercospora arachidicola, Physalospora piricola, Rhizoctonia cerealis, and Fusarium moniliforme.

Benzimidazole-oxindole hybrids as multi-kinase inhibitors targeting melanoma.

In the current study, a series of benzimidazole-oxindole conjugates 8a-t were designed and synthesized as type II multi-kinase inhibitors. They exhibited moderate to potent inhibitory activity against BRAFWT up to 99.61 % at 10 µM. Notably, compounds 8e, 8k, 8n and 8s demonstrated the most promising activity, with 99.44 to 99.61 % inhibition. Further evaluation revealed that 8e, 8k, 8n and 8s exhibit moderate to potent inhibitory effects on the kinases BRAFV600E, VEGFR-2, and FGFR-1. Additionally, compounds 8a-t were screened for their cytotoxicity by the NCI, and several compounds showed significant growth inhibition in diverse cancer cell lines. Compound 8e stood out with a GI50 range of 1.23 - 3.38 µM on melanoma cell lines. Encouraged by its efficacy, it was further investigated for its antitumor activity and mechanism of action, using sorafenib as a reference standard. The hybrid compound 8e exhibited potent cellular-level suppression of BRAFWT, VEGFR-2, and FGFR-1 in A375 cell line, surpassing the effects of sorafenib. In vivo studies demonstrate that 8e significantly inhibits the growth of B16F10 tumors in mice, leading to increased survival rates and histopathological tumor regression. Furthermore, 8e reduces angiogenesis markers, mRNA expression levels of VEGFR-2 and FGFR-1, and production of growth factors. It also downregulated Notch1 protein expression and decreased TGF-ß1 production. Molecular docking simulations suggest that 8e binds as a promising type II kinase inhibitor in the target kinases interacting with the key regions in their kinase domain.

Novel sulfonamide-indolinone hybrids targeting mitochondrial respiration of breast cancer cells.

Breast cancer (BC) still poses a threat worldwide which demands continuous efforts to present safer and efficacious treatment options via targeted therapy. Beside kinases' aberrations as Aurora B kinase which controls cell division, BC adopts distinct metabolic profiles to meet its high energy demands. Accordingly, targeting both aurora B kinase and/or metabolic vulnerability presents a promising approach to tackle BC. Based on a previously reported indolinone-based Aurora B kinase inhibitor (III), and guided by structural modification and SAR investigation, we initially synthesized 11 sulfonamide-indolinone hybrids (5a-k), which showed differential antiproliferative activities against the NCI-60 cell line panel with BC cells displaying preferential sensitivity. Nonetheless, modest activity against Aurora B kinase (18-49% inhibition) was noted at 100 nM. Screening of a representative derivative (5d) against 17 kinases, which are overexpressed in BC, failed to show significant activity at 1 µM concentration, suggesting that kinase inhibitory activity only played a partial role in targeting BC. Bioinformatic analyses of genome-wide transcriptomics (RNA-sequencing), metabolomics, and CRISPR loss-of-function screens datasets suggested that indolinone-completely responsive BC cell lines (MCF7, MDA-MB-468, and T-47D) were more dependent on mitochondrial oxidative phosphorylation (OXPHOS) compared to partially responsive BC cell lines (MDA-MB-231, BT-549, and HS 578 T). An optimized derivative, TC11, obtained by molecular hybridization of 5d with sunitinib polar tail, manifested superior antiproliferative activity and was used for further investigations. Indeed, TC11 significantly reduced/impaired the mitochondrial respiration, as well as mitochondria-dependent ROS production of MCF7 cells. Furthermore, TC11 induced G0/G1 cell cycle arrest and apoptosis of MCF7 BC cells. Notably, anticancer doses of TC11 did not elicit cytotoxic effects on normal cardiomyoblasts and hepatocytes. Altogether, these findings emphasize the therapeutic potential of targeting the metabolic vulnerability of OXPHOS-dependent BC cells using TC11 and its related sulfonamide-indolinone hybrids. Further investigation is warranted to identify their precise/exact molecular target.

C3-Spirooxindoles: Divergent chemical synthesis and bioactivities (2018-2023).

This scientific review documents the recent progress of C3-spirooxindoles chemistry (synthesis and reaction mechanism) and their bioactivities, focusing on the promising results as well as highlighting the biological mechanism via the reported molecular docking findings of the most bioactive derivatives. C3-Spirooxindoles are attractive bioactive agents and have been found in a variety of natural compounds, including alkaloids. They are widely investigated in the field of medicinal chemistry and play a key role in medication development, such as antivirals, anticancer agents, antimicrobials, etc. Regarding organic synthesis, several traditional and advanced strategies have been reported, particularly those that started with isatin derivatives.

Design and Synthesis of New bis-oxindole and Spiro(triazole-oxindole) as CDK4 Inhibitors with Potent Anti-breast Cancer Activity.

BACKGROUND: Since CDKs have been demonstrated to be overexpressed in a wide spectrum of human malignancies, their inhibition has been cited as an effective technique for anticancer drug development. METHODS: In this context, new bis-oxindole/spiro-triazole-oxindole anti-breast cancer drugs with potential CDK4 inhibitory effects were produced in this work. The novel series of bis-oxindole/spirotriazole- oxindole were synthesized from the reaction of bis-oxindole with the aniline derivatives then followed by 1,3-dipolar cycloaddition of hydrazonoyl chloride. RESULTS: The structure of these bis-oxindole/spiro-triazole-oxindole series was proven based on their spectral analyses. Most bis-oxindole and bis-spiro-triazole-oxindole compounds effectively inhibited the growth of MCF-7 (IC50 = 2.81-17.61 µM) and MDA-MB-231 (IC50 = 3.23-7.98 µM) breast cancer cell lines with low inhibitory activity against normal WI-38 cells. While the reference doxorubicin showed IC50 values of 7.43 µM against MCF-7 and 5.71 µM against the MDA-MB-231 cell line. Additionally, compounds 3b, 3c, 6b, and 6d revealed significant anti-CDK4 activity (IC50 = 0.157- 0.618 µM) compared to palbociclib (IC50 = 0.071 µM). Subsequent mechanistic investigations demonstrated that 3c was able to trigger tumor cell death through the induction of apoptosis. Moreover, it stimulated cancer cell cycle arrest in the G1 phase. Furthermore, western blotting disclosed that the 3c-induced cell cycle arrest may be mediated through p21 upregulation. CONCLUSION: According to all of the findings, bis-oxindole 3c shows promise as a cancer treatment targeting CDK4.

An Integrative Approach to Study the Inhibition of Providencia vermicola FabD Using C2-Quaternary Indolinones.

Background: The present study investigates the potential bioactivity of twelve experimentally designed C-2 quaternary indolinones against Providencia spp., a bacterial group of the Enterobacteriaceae family known to cause urinary tract infections. The study aims to provide insights into the bioactive properties of the investigated compounds and their potential use in developing novel treatments against Providencia spp. The experimental design of indolinones, combined with their unique chemical structure, makes them attractive candidates for further investigation. The results of this research may contribute to the development of novel therapeutic agents to combat Providencia spp. infections. Methods: The synthesized indolinones (moL1-moL12) are evaluated to identify any superior activity, particularly focusing on moL12, which possesses aza functionality. The antimicrobial activities of all twelve compounds are tested in triplicates against six different Gram-positive and Gram-negative organisms, including P. vermicola (P<0.05). Computational methods have been employed to assess the pharmacokinetic properties of the compounds. Results: Among the synthesized indolinones, moL12 exhibits superior activity compared to the other compounds with similar skeleton but different functional moieties. All six strains tested, including P. vermicola, demonstrated sensitivity to moL12. Computational studies support the pharmacokinetic properties of moL12, indicating acceptable absorption, distribution, metabolism, excretion, and toxicity characteristics. Conclusion: Utilizing the PPI approach, we have identified a promising target, FabD, in Gram-negative bacteria. Our analysis has shown that moL12 exhibits significant potential in binding with FabD, thereby, might inhibit cell wall formation, and display superior antimicrobial activity compared to other compounds. Consequently, moL12 may be a potential therapeutic agent that could be used to combat urinary tract infections caused by Providencia spp. The findings of this research hold significant promise for the development of new and effective treatments for bacterial infections.

Novel spirooxindole alkaloid derivatives from the medicinal insect Blaps japanensis and their biological evaluation.

Blapspirooxindoles A-C (1-3), three novel spirooxindole alkaloids with a unique spiro[chromane-4,3'-indoline]-2,2'-dione motif, blapcumaranons A and B (4 and 5), two new 2-cumaranon derivatives, blapoxindoles A-J (6-15), ten new oxindole alkaloid derivatives, along with one known compound (16), were isolated from the whole bodies of Blaps japanensis. Their structures including absolute configurations were determined by using spectroscopic, X-ray crystallographic, and computational methods. Compounds 1-11 and 13 exist as racemic mixtures in nature, and their (-)- and (+)-antipodes were separated by chiral HPLC. Biological evaluations of these compounds were determined with multiple assays including anti-tumor, anti-inflammatory, and renal protection activities in vitro. Several compounds displayed effective activity in one or more assays.

The Discovery of Novel Small Oxindole-Based Inhibitors Targeting the SARS-CoV-2 Main Protease (Mpro ).

With the potential for coronaviruses to re-emerge and trigger future pandemics, the urgent development of antiviral inhibitors against SARS-CoV-2 is essential. The Mpro enzyme is crucial for disease progression and the virus's life cycle. It possesses allosteric sites that can hinder its catalytic activity, with some of these sites located at or near the dimerization interface. Among them, sites #2 and #5 possess druggable pockets and are predicted to bind drug-like molecules. Consequently, a commercially available ligand library containing ~7 million ligands was used to target site #2 via structure-based virtual screening. After extensive filtering, docking, and post-docking analyses, 53 compounds were chosen for biological testing. An oxindole derivative was identified as a Mpro non-competitive reversible inhibitor with a Ki of 115 µM and an IC50 of 101.9 µM. Throughout the 200 ns-long MD trajectories, our top hit has shown a very stable binding mode, forming several interactions with residues in sites #2 and #5. Moreover, derivatives of our top hit were acquired for biological testing to gain deeper insights into their structure-activity relationship. To sum up, drug-like allosteric inhibitors seem promising and can provide us with an additional weapon in our war against the recent pandemic, and possibly other coronaviruses-caused diseases.

Oxindole and Benzoxazinone Alkaloids from the Seeds of Persea americana (Avocado) and Their SIRT1 Stimulatory Activity.

Persea americana Mill. (Lauraceae), commonly known as avocado, is a well-known food because of its nutrition and health benefits. The seeds of avocado are major byproducts, and thus their phytochemicals and bioactivities have been of interest for study. The chemical components of avocado seeds were investigated by using UPLC-qTOF-MS/MS-based molecular networking, resulting in the isolation of seven new oxindole alkaloids (1-7) and two new benzoxazinone alkaloids (8 and 9). The chemical structures of the isolated compounds were identified by the analysis of NMR data in combination with computational approaches, including NMR and ECD calculations. Bioactivities of the isolated compounds toward silent information regulation 2 homologue-1 (SIRT1) in HEK293 cells were assessed. The results showed that compound 1 had the most potent effect on SIRT1 activation with an elevated NAD+/NADH ratio with potential for further investigation as an anti-aging agent.

Synthesis of Novel Pyrazole-Oxindole Conjugates with Cytotoxicity in Human Cancer Cells via Apoptosis.

A novel series of pyrazole-oxindole conjugates were prepared and characterized as potential cytotoxic agents by FT-IR, NMR and HR-MS. The cytotoxic activity of these compounds was tested in the Jurkat acute T cell leukemia, CEM acute lymphoblastic leukemia, MCF10 A mammary epithelial and MDA-MB 231 triple negative breast cancer cell lines. Among the tested conjugates, 5-methyl-3-((3-(1-phenyl)-3-(p-tolyl)-1H-pyrazol-4-yl)methylene)indolin-2-one 6h emerged as the most cytotoxic with a CC50 of 4.36+/-0.2 µM against Jurkat cells. The mechanism of cell death induced by 6h was investigated through the Annexin V-FITC assay via flow cytometry. Reactive oxygen species (ROS) accumulation, mitochondrial health and the cell cycle progression were also evaluated in cells exposed to 6h. Results demonstrated that 6h induces apoptosis in a dose-response manner, without generating ROS and/or altering mitochondrial health. In addition, 6h disrupted the cell cycle distribution causing an increase in DNA fragmentation (Sub G0-G1), and an arrest in the G0-G1 phase. Taken together, the 6h compound revealed a strong potential as an antineoplastic agent evidenced by its cytotoxicity in leukemia cells, the activation of apoptosis and restriction of the cell cycle progression.

Combination of an Oxindole Derivative with (-)-ß-Elemene Alters Cell Death Pathways in FLT3/ITD+ Acute Myeloid Leukemia Cells.

Acute myeloid leukemia (AML) is one of the cancers that grow most aggressively. The challenges in AML management are huge, despite many treatment options. Mutations in FLT3 tyrosine kinase receptors make the currently available therapies less responsive. Therefore, there is a need to find new lead molecules that can specifically target mutated FLT3 to block growth factor signaling and inhibit AML cell proliferation. Our previous studies on FLT3-mutated AML cells demonstrated that ß-elemene and compound 5a showed strong inhibition of proliferation by blocking the mutated FLT3 receptor and altering the key apoptotic genes responsible for apoptosis. Furthermore, we hypothesized that both ß-elemene and compound 5a could be therapeutically effective. Therefore, combining these drugs against mutated FLT3 cells could be promising. In this context, dose-matrix combination-based cellular inhibition analyses, cell morphology studies and profiling of 43 different apoptotic protein targets via combinatorial treatment were performed. Our studies provide strong evidence for the hypothesis that ß-elemene and compound 5a combination considerably increased the therapeutic potential of both compounds by enhancing the activation of several key targets implicated in AML cell death.

Optimization and Antibacterial Evaluation of Novel 3-(5-Fluoropyridine-3-yl)-2-oxazolidinone Derivatives Containing a Pyrimidine Substituted Piperazine.

In this study, a series of novel 3-(5-fluoropyridine-3-yl)-2-oxazolidinone derivatives were designed and synthesized based on compounds previously reported, and their antibacterial activity was investigated. Then their antibacterial activity was investigated for the first time. Preliminary screening results showed that all these compounds exhibited antibacterial activity against gram-positive bacteria, including 7 drug-sensitive strains and 4 drug-resistant strains, among which compound 7j exhibited an 8-fold stronger inhibitory effect than linezolid, with a minimum inhibitory concentration (MIC) value of 0.25 µg/mL. Further molecular docking studies predicted the possible binding mode between active compound 7j and the target. Interestingly, these compounds could not only hamper the formation of biofilms, but also have better safety, as confirmed by cytotoxicity experiments. All these results indicate that these 3-(5-fluoropyridine-3-yl)-2-oxazolidinone derivatives have the potential to be developed into novel candidates for the treatment of gram-positive bacterial infections.

Simple and Efficient Synthesis of 3-Aryl-2-oxazolidinone Scaffolds Enabling Increased Potency toward Biofilms.

Infectious diseases caused by bacterial pathogens are a leading cause of mortality worldwide. In particular, recalcitrant bacterial communities known as biofilms are implicated in persistent and difficult to treat infections. With a diminishing antibiotic pipeline, new treatments are urgently required to combat biofilm infections. An emerging strategy to develop new treatments is the hybridization of antibiotics. The benefit of this approach is the extension of the useful lifetime of existing antibiotics. The oxazolidinones, which include the last resort antibiotic linezolid, are an attractive target for improving antibiofilm efficacy as they present one of the most recently discovered classes of antibiotics. A key step in the synthesis of new 3-aryl-2-oxazolidinone derivatives is the challenging formation of the oxazolidinone ring. Herein we report a direct synthetic route to the piperazinyl functionalized 3-aryl-2-oxazolidinone 17. We also demonstrate an application of these piperazine molecules by functionalizing them with a nitroxide moiety as a strategy to extend the useful lifetime of oxazolidinones and improve their potency against Methicillin-resistant Staphylococcus aureus (MRSA) biofilms. The antimicrobial susceptibility of the linezolid-nitroxide conjugate 11 and its corresponding methoxyamine derivative 12 (a control for biofilm dispersal) was assessed against planktonic cells and biofilms of MRSA. In comparison to linezolid and our lead compound 10 (a piperazinyl oxazolidinone derivative), the linezolid-nitroxide conjugate 11 displayed a minimum inhibitory concentration that was 4-16-fold higher. The opposite effect was seen in biofilms where the linezolid-nitroxide hybrid 11 was >2-fold more effective (160 µg/mL versus >320 µg/mL) in eradicating MRSA biofilms. The methoxyamine derivative 12 performed on par with linezolid. The drug-likeness of the compounds was also assessed, and all compounds were predicted to have good oral bioavailability. Our piperazinyl oxazolidinone derivative 10 was confirmed to be lead-like and would be a good lead candidate for future functionalized oxazolidinones. The modification of antibiotics with a dispersal agent appears to be a promising approach for eradicating MRSA biofilms and overcoming the antibiotic resistance associated with the biofilm mode of growth.

Synthesis and SARs study of novel spiro-oxindoles as potent antiproliferative agents with CDK-2 inhibitory activities.

A series of 16 novel spirooxindole analogs 8a-p were designed and constructed via cost-effective single-step multicomponent [3+2] cycloaddition reaction of azomethine ylide (AY) generated in situ from substituted isatin (6a-d) with suitable amino acids (7a-c) and ethylene-engrafted pyrazole derivatives (5a,b). The potency of all compounds was assayed against a human breast cancer cell line (MCF-7) and a human liver cell line (HepG2). Spiro compound 8c was the most active member among the synthesized candidates, with exceptional cytotoxicity against the MCF-7 and HepG2 cell lines, with IC50 values of 0.189 ± 0.01 and 1.04 ± 0.21 µM, respectively. The candidate 8c exhibited more potent activity (10.10- and 2.27-fold) than the standard drug roscovitine (IC50 = 1.91 ± 0.17 µM (MCF-7) and 2.36 ± 0.21 µM (HepG2)). Compound 8c was investigated for epidermal growth factor receptor (EGFR) inhibition; it exhibited promising IC50 values of 96.6 nM compared with 67.3 nM for erlotinib. The IC50 value of 8c (34.98 nM) exhibited cyclin-dependent kinase 2 (CDK-2) inhibition, being more active than roscovitine the (IC50 = 140 nM) in targeting the CDK-2 kinase enzyme. Additionally, for apoptosis induction of compound 8c in MCF-7, it upregulated the expression levels of proapoptotic genes for P53, Bax, caspases-3, 8, and 9 at up to 6.18, 4.8, 9.8, 4.6, 11.3 fold-change, respectively, and downregualted the level of the antiapoptotic gene for Bcl-2 by 0.14-fold. Finally, a molecular docking study of the most active compound 8c highlighted a good binding affinity with Lys89 as the key amino acid for CDK-2 inhibition.

Physicochemical properties, drug likeness, ADMET, DFT studies, and in vitro antioxidant activity of oxindole derivatives.

Poor pharmacokinetic and safety profiles create significant hurdles in the drug development process. This work focuses on a detailed understanding of drug discovery interplay among physicochemical, pharmacokinetic, toxicity endpoints, and antioxidant properties of oxindole derivatives. DFT compiutations were also performed at B3LYP/6-311G** level to evaluate the physicochemical properties, global reactivity features, and intramolecular interactions. The BOILED-Egg pharmacokinetic model envisaged gastrointestinal absorption, blood-brain barrier penetration, and no interaction with p-glycoprotein for compounds C1 and C2. The physicochemical evaluation revealed that C1 possesses superior drug-like properties fit for oral absorption. Both derivatives were predicted to have high plasma protein binding, efficient distribution, and inhibiting CYP 450 major isoforms but serve as substrates only for a few of them. Both molecules have mild to moderate clearance rates. Out of ten toxicity parameters, only hepatotoxicity was predicted. DFT results implied that the meta position of the -OH group made the possibility of charge transfer greater than -para positioned -OH, due to the ΔNmax (eV) values of molecules C1 and C2 being calculated at 2.596 and 2.477, respectively. Both C1 and C2 exhibited a concentration dependant DPPH and ABTS radical scavenging activity. The chemical structure-physicochemical-pharmacokinetic relationship identified the meta position as the favorite for the electron-withdrawing hydroxyl group. This provides useful insight to medicinal chemists to design 6-chlorooxindole derivatives with an acceptable drug-like and pharmacokinetic property.

Antiferroptotic Activities of Oxindole GIF-0726-r Derivatives: Involvement of Ferrous Iron Coordination and Free-Radical Scavenging Capacities.

Ferroptosis and oxytosis are iron- and oxidative stress-dependent cell death pathways strongly implicated in neurodegenerative diseases, cancers, and metabolic disorders. Therefore, specific inhibitors may have broad clinical applications. We previously reported that 3-[4-(dimethylamino)benzyl]-2-oxindole (GIF-0726-r) and derivatives protected the mouse hippocampal cell line HT22 against oxytosis/ferroptosis by suppressing reactive oxygen species (ROS) accumulation. In this study, we evaluated the biological activities of GIF-0726-r derivatives with modifications at the oxindole skeleton and other positions. The addition of a methyl, nitro, or bromo group to C-5 of the oxindole skeleton enhanced antiferroptotic efficacy on HT22 cells during membrane cystine-glutamate antiporter inhibition and ensued intracellular glutathione depletion. In contrast, the substitution of the dimethylamino group on the side chain phenyl ring with a methyl, nitro, or amine group dramatically suppressed antiferroptotic activity regardless of other modifications. Compounds with antiferroptotic activity also directly scavenged ROS and decreased free ferrous ions in both HT22 cells and cell-free reactions while those compounds without antiferroptotic activity had little effect on either ROS or ferrous-ion concentration. Unlike oxindole compounds, which we have previously reported, the antiferroptotic compounds had little effect on the nuclear factor erythroid-2-related factor 2-antioxidant response element pathway. Oxindole GIF-0726-r derivatives with a 4-(dimethylamino)benzyl moiety at C-3 and some types of bulky group at C-5 (whether electron-donating or electron-withdrawing) can suppress ferroptosis, warranting safety and efficacy evaluations in animal models of disease.

3-Arylidene-2-oxindoles as GSK3ß inhibitors and anti-thrombotic agents.

Development of novel agents that prevent thrombotic events is an urgent task considering increasing incidence of cardiovascular diseases and coagulopathies that accompany cancer and COVID-19. Enzymatic assay identified novel GSK3ß inhibitors in a series of 3-arylidene-2-oxindole derivatives. Considering the putative role of GSK3ß in platelet activation, the most active compounds were evaluated for antiplatelet activity and antithrombotic activity. It was found that GSK3ß inhibition by 2-oxindoles correlates with inhibition of platelet activation only for compounds 1b and 5a. Albeit, in vitro antiplatelet activity matched well with in vivo anti-thrombosis activity. The most active GSK3ß inhibitor 5a exceeds antiplatelet activity of acetylsalicylic acid in vitro by 10.3 times and antithrombotic activity in vivo by 18.7 times (ED50 7.3 mg/kg). These results support the promising role of GSK3ß inhibitors for development of novel antithrombotic agents.