Recent advances in isatin hybrids as potential anticancer agents

Targeting sensitive and multidrug resistant leukemia cells with a novel benzofuran-isatin conjugate

Benzofuran-isatin conjugates are considered as promising compounds in cancer prevention and treatment. However, it is not known yet whether these compounds are useful to effectively treat multidrug-resistant tumors. In this study, we investigated the activity of G-5e, a novel benzofuran-isatin conjugate in a panel of cell lines exhibiting well-known drug resistance mechanisms (P-gp, BCRP, TP53, EGFR). P-glycoprotein overexpressing CEM/ADR5000 cell line displayed notable hypersensitivity (collateral sensitivity) to G-5e, which was mediated through autophagic cell death activation including downregulation of the autophagy suppressor RND2, upregulation of the autophagy inducer LC3B, and G0/G1 phase arrest during cell cycle progression. Independent of collateral sensitivity, transcriptomic analyses also revealed that G-5e caused downregulation of NF-κB and ERK1/2 pathways. Our findings highlight the potential of benzofuran-isatin conjugates to combat multidrug resistance and the role of RND2 for collateral sensitivity.

A survey of isatin hybrids and their biological properties

The emergence of diverse infections worldwide, which is a serious global threat to human existence, necessitates the urgent development of novel therapeutic candidates that can combat these diseases with efficacy. Molecular hybridization has been established as an efficient technique in designing bioactive molecules capable of fighting infections. Isatin, a core nucleus of an array of compounds with diverse biological properties can be modified at different positions leading to the creation of novel drug targets, is an active area of medicinal chemistry. This review containing published articles from 2005 to 2022 highlights isatin hybrids which have been synthesized and reported in the literature alongside a discussion on their biological properties. The enriched structure-activity relationship studies discussed provides insights for the rational design of novel isatin hybrids with tailored biological properties as effective therapeutic candidates inspired by nature.

CO2•- Enabled Synthesis of Phenanthridinones, Oxindoles, Isoindolinones, and Spirolactams

We report herein that photoinduced CO2•- enabled reductive intramolecular radical cyclization of a variety of aryl iodide derivatives to the corresponding phenanthridinone, oxindole, isoindolinone, and spirolactam derivatives in good yields. Preliminary mechanistic studies suggested the generation of CO2•- through homolysis of cesium formate in the presence of light, and the further involvement of CO2•- and the aryl radical was directly proved by trapping with diphenyl styrene and TEMPO.

Synthesis, anti-proliferation, apoptosis induction in breast cancer cells, and aromatase inhibition of coumarin-triazole hybrids: In vitro and in silico studies

Breast cancer is one of the most common cancers found in women worldwide. Besides the availability of clinical drugs, drug resistance and considerable side effects are concerning issues driven the needs for the discovery of novel anticancer agents. Aromatase inhibition is one of the effective strategies for management of hormone-dependent breast cancer. Triazole, coumarin, and isatin are heterocyclic scaffolds holding great attention in the field of drug design. Molecular hybridization is a well-known strategy to achieve new molecules with improved potency and properties. Herein, a set of 27 triazole-based hybrids (i.e., coumarin-triazoles series 5-6 and isatin-triazoles series 7) were synthesized and investigated for their anti-proliferation, apoptosis induction, and aromatase inhibitory potentials. Anti-proliferative study against the hormone-dependent breast cancer (T47D) cell line indicated that coumarin-triazoles 5h (R=NO2) and 6i (R=SO2NH2) were the two most potent antiproliferative agents. Particularly, compound 5h showed comparable potency and superior selectivity index than that of the reference drug, doxorubicin. Moreover, the coumarin-triazole 5h induced cellular apoptosis of the estrogen-dependent breast cancer (MCF-7) cells. Additionally, findings from the aromatase inhibitory assay suggested four compounds as potential aromatase inhibitors (i.e., 5i, 6f, 6g and 6i, IC50 = 1.4-2.4 μM). Two QSAR models with preferable predictive performances were constructed to reveal key properties influencing antiproliferative and aromatase inhibitory effects. Molecular docking was conducted to elucidate the possible binding modalities against the target aromatase enzyme. Key structural features essential for the binding were highlighted. Moreover, the drug-like properties of top-ranking compounds were assessed to ensure their possibilities for successful development.

Synthesis, Biological Activities, and Molecular Docking Studies of 15-Site Matrine Based Isatohydrazone Derivatives as Potential Anticancer Agents

To acquire matrine derivatives with enhanced anticancer activity, we designed and synthesized twenty-one 15-site matrine based isatohydrazone derivatives were designed and synthesized. The anti-proliferative activity of all the compounds against human cervical cancer cells (HeLa), human colon cancer cells (HCT116), and non-small cell lung cancer cells (A549) was examined by the MTT method. The majority of the compounds exhibited superior anticancer activity compared to matrine. Among them, compound 5a displayed the most potent anti-proliferative activity, with IC50 values of 9.02±0.33 μM (HeLa), 10.49±1.09 μM (HCT116), and 15.23±0.12 μM (A549), respectively. Compound 5a can also induce cell cycle arrest in the G0/G1 phase and trigger apoptosis, as well as inhibit cell clonal formation and migration. Molecular docking experiments have demonstrated that compound 5a can form hydrogen bonds and hydrophobic interactions with EGFR-related protein 7AEI.

Design, Synthesis, and Cytotoxicity Evaluation of Novel Indolin-2-One Based Molecules on Hepatocellular Carcinoma HepG2 Cells as Protein Kinase Inhibitors

A series of indolinone-based derivatives were designed and synthesized using the hybrid pharmacophoric design approach as cytotoxic kinase inhibitors. The cytotoxic effects of the designed molecules were tested against MCF-7 and HepG-2 cell lines. Compounds 9 and 20 were the most cytotoxic, with IC50 values against HepG-2 and MCF-7 cells ranging from 2.53 to 7.54 µM. Additionally, compounds 9 and 20 were also found to be slightly more cytotoxic than indirubin with 2.2-2.7-fold higher cytotoxicity with HepG-2 cells. CDK-2 and CDK-4 kinase enzyme inhibition assay showed that compound 9 had a higher inhibitory effect (4.8-fold) than indirubin against CDK-2 and comparable inhibition against CDK-4. Moreover, compound 20 displayed nanomolar inhibitory action against both EGFR kinase and VFGFR-2 enzyme, which were around 8.8- and 5.4-fold higher than the IC50 values of indirubin. Compounds 9 and 20 induced cell cycle arrest at the G1 phase on HepG2 cells. The levels of the key apoptotic proteins assessed revealed elevated levels of the Bax/Bcl-2 ratio, which in turn initiated the caspase3/7 cascade that led to the activation of both intrinsic and extrinsic apoptotic pathways. The cell cycle inhibitory proteins p53 and p21 were significantly upregulated upon treatment with compounds 9 and 20. The docking results revealed that compound 9 exhibits stronger binding affinity to CDK-2 than indirubin, and compound 20 showed a similar binding mode to sorafenib with VEGFR-2.

Copper(II)-Catalyzed Enantioselective Addition of Aryl Amines to Isatin-Derived N-Boc-Ketimines for the Synthesis of Acyclic N,N'-Ketals

Here, we demonstrated a copper(II)-catalyzed enantioselective addition of aryl amines to isatin-derived N-Boc-ketimines using chiral O-N-N tridentate ligands derived from BINOL and proline. Generally, the chiral acyclic N,N'-ketals were obtained in high yields (up to 98%) and excellent ee values (up to 98%). Various aryl amines could be tolerated and a gram-scale reaction was also possible. Further, an X-ray diffraction experiment confirmed that the configuration of isatin-derived N-Boc ketimine should be (Z). Confirmation of the configuration of the ketimine would make it easier to understand the rationale for stereofacial selective activation of the electrophile with either organo- or Lewis acid-based catalysts.

Design, synthesis, in vitro, and in silico studies of novel isatin-hybrid hydrazones as potential triple-negative breast cancer agents

Recent advances in cancer therapy have been made possible by monoclonal antibodies, domain antibodies, antibody drug conjugates, etc. The most impact has come from controlling cell cycle checkpoints through checkpoint inhibitors. This manuscript explores the potential of a series of novel N-benzyl isatin based hydrazones (5-25), which were synthesized and evaluated as anti-breast cancer agents. The synthesized hydrazones of N-benzyl isatin were screened in vitro against two cell lines, the MDA-MB-231 breast cancer cell line and the MCF-10A breast epithelial cell line. The results indicated that all compounds showed great potential against the triple-negative MDA-MB-231 breast cancer cell line. Compound 23 with nitro substitution at the 4th position of the phenyl ring exhibited significant antiproliferative potential for the MDA-MB-231 with an IC50 value of 15.8 ± 0.6 μM. Molecular dynamics and molecular docking simulations were performed to get a deeper understanding of the interactions between the synthesized compounds and cancer cells.

Multi-target directed ligands inspired natural products as an effective approach for the treatment of complex chronic health disorders

Complex diseases involve multifaceted etiological components, which limit the effectiveness of conventional targeted therapies. Therefore, standard medicinal treatments often face significant challenges and failures when addressing these disease conditions. Furthermore, the growing interest in multidrug resistance (MDR), the occurrence of adverse drug reactions related to use traditional approaches, and the limited clinical efficacy of single-target drug therapy have increased the demand for innovative drug treatments. In this rapidly evolving era, the exploration of multi-target directed ligands (MTDLs) derived from natural products has granted us access to a wide range of compounds with medicinal properties. The allure of these MTDLs lies in their unique ability to minimize side effects from using two medicinal agents, establishing them as the preferred choice for drug developers. MTDLs have been recognized for their extraordinary capacity to collectively hinder multiple pathways implicated in the development of intricate diseases by merging or linking active molecules obtained from these sources. This review delves into promising MTDLs derived from natural products, which modulates diverse biological pathways implicated in complex diseased conditions particularly Alzheimer's disease, diabetes, cardiac disorders and inflammatory conditions.

Intramolecular cyclization of N-aryl amides for the synthesis of 3-amino oxindoles

A mild and efficient strategy to synthesize pharmaceutically important 3-amino oxindoles from readily available N-aryl amides has been developed. This unique reaction proceeds via the intramolecular cyclization of 2-azaallyl anions with N-aryl amides to afford 3-amino substituted oxindoles. This novel method avoids the direct usage of transition metal catalysts and additional oxidants. Furthermore, the anti-pulmonary fibrosis activity evaluation showed that 3-amino oxindole 2f significantly inhibited collagen deposition, which can ameliorate pulmonary fibrosis by reducing excessive extracellular matrix (ECM) deposition.

Preliminary evaluation of antiproliferative and apoptotic activities of novel indolin-2-one derivatives

Indole-based agents are frequently used in targeted or supportive therapy of several cancers. In this study, we investigated the anticancer properties of originally synthesized novel indolin-2-one derivatives (6a-d) against Malignant Mesothelioma, Breast cancer, and Colon Cancer cells. Our results revealed that all derivatives were effectively delayed cell proliferation by inhibiting the ERK1/2, AKT, and STAT3 signaling pathways in a concentration-dependent manner. Additionally, these variants induced cell cycle arrest in the S phase, accompanied by elevated levels of p21 and p27 expressions. Derivatives also initiated mitochondrial apoptosis through the upregulation of Bax and downregulation of Bcl-2 proteins, leading to the activation of caspase 3 and PARP cleavage in exposed cells. Remarkably, three of the indolin-2-one derivatives displayed significant selectivity towards Breast and Colon Cancer cells, with compound 6d promising as the most potent and wide spectral one for all cancer cell lines.

Investigation of the effects of thiazole compounds on thioredoxin reductase 1 (TrxR1), glutathione S-transferase (GST), and glutathione reductase (GR) targeted human brain glioblastoma cancer (U-87 MG)

Cancer is a fatal disease that kills thousands of people worldwide. Despite the information produced by research on cancer treatment, applications in cancer treatment are limited. Therefore, scientists' efforts to develop more effective treatment approaches continue. In the study, we aimed to determine the anticancer potential of amino thiazole compounds on human glioblastoma (U-87 MG) and human dermal fibroblast (HDFa) cells and their inhibition effects on enzymes that cause multidrug resistance in cancer cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide cell viability test was performed to understand the cytotoxic properties of thiazole derivatives. The cellular death mechanisms behind thiazole application were investigated using flow cytometry analysis. According to cell viability analysis, thiazole derivatives exhibited a greater effect on U-87 MG than the HDFa cell line in terms of cytotoxicity. Flow cytometry showed higher apoptotic cell death in U-87 MG cells than in the HDFa cell line. It can be concluded that thiazole compounds exert anticancer effects on U-87 MG and HDFa as well as show apoptotic properties. Their effects on thioredoxin reductase 1 (TrxR1), glutathione S-transferase (GST), and glutathione reductase (GR) activities, which are important in the development of chemotherapeutic methods, were also examined. From the results obtained, it was determined that the 2-amino-4-(p-tolyl)thiazole (T7) compound significantly suppressed both TrxR1 and GST activities, and the 2-amino-6-methylbenzothiazole (T8) compound significantly suppressed both TrxR1 and GST activities. Compound T7 was determined to be a selective inhibitor for TrxR1 and GST targeting, and compound T8 was determined to be a selective inhibitor for TrxR1 and GR targeting glioblastoma treatment.

Discovery and prospects of new heterocyclic Isatin-hydrazide derivative with a novel role as estrogen receptor α degrader in breast cancer cells

Introduction: Isatin, a heterocycle scaffold, is the backbone of many anticancer drugs and has previously been reported to engage multiple cellular targets and mechanisms, including angiogenesis, cell cycle, checkpoint pathways and multiple kinases. Here, we report that a novel isatin derivative, 5i, degrades estrogen receptor alpha (ERα) in estrogen-dependent breast cancer cells. This effect of the isatin nucleus has not been previously reported. Tamoxifen and fulvestrant represent standard therapy options in estrogen-mediated disease but have their own limitations. Isatin-based triple angiokinase inhibitor BIBF1120 (Nintedanib) and multikinase inhibitor Sunitinib (Sutent) have been approved by the FDA. Methods: Keeping this in view, we synthesized a series of N'-(1-benzyl-2-oxo-1, 2-dihydro-3H-indol-3-ylidene) hydrazide derivatives and evaluated them in vitro for antiproliferative activities in MCF-7 (ER+) cell line. We further investigated the effect of the most potent compound (5i) on the Erα through Western Blot Analysis. We used in silico pharmacokinetics prediction tools, particularly pkCSM tool, to assess the activity profiles of the compounds. Results and discussion: Compound 5i showed the best antiproliferative activity (IC50 value; 9.29 ± 0.97 µM) in these cells. Furthermore, 5i downregulated ERα protein levels in a dose-dependent manner in MCF-7. A multifaceted analysis of physicochemical properties through Data Warrior software revealed some prominent drug-like features of the synthesized compounds. The docking studies predicted the binding of ligands (compounds) with the target protein (ERα). Finally, molecular dynamics (MD) simulations indicated stable behavior of the protein-ligand complex between ERα and its ligand 5i. Overall, these results suggest that the new isatin derivative 5i holds promise as a new ERα degrader.

Therapeutic bacteria and viruses to combat cancer: double-edged sword in cancer therapy: new insights for future

Cancer, ranked as the second leading cause of mortality worldwide, leads to the death of approximately seven million people annually, establishing itself as one of the most significant health challenges globally. The discovery and identification of new anti-cancer drugs that kill or inactivate cancer cells without harming normal and healthy cells and reduce adverse effects on the immune system is a potential challenge in medicine and a fundamental goal in Many studies. Therapeutic bacteria and viruses have become a dual-faceted instrument in cancer therapy. They provide a promising avenue for cancer treatment, but at the same time, they also create significant obstacles and complications that contribute to cancer growth and development. This review article explores the role of bacteria and viruses in cancer treatment, examining their potential benefits and drawbacks. By amalgamating established knowledge and perspectives, this review offers an in-depth examination of the present research landscape within this domain and identifies avenues for future investigation.

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.

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.

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.

Thiazole, Isatin and Phthalimide Derivatives Tested in vivo against Cancer Models: A Literature Review of the Last Six Years

BACKGROUND

Cancer is a disease characterized by the abnormal multiplication of cells and is the second leading cause of death in the world. The search for new effective and safe anticancer compounds is ongoing due to factors such as low selectivity, high toxicity, and multidrug resistance. Thus, heterocyclic compounds derived from isatin, thiazole and phthalimide that have achieved promising in vitro anticancer activity have been tested in vivo and in clinical trials.

OBJECTIVE

This review focused on the compilation of promising data from thiazole, isatin, and phthalimide derivatives, reported in the literature between 2015 and 2022, with in vivo anticancer activity and clinical trials.

METHODS

A bibliographic search was carried out in the PUBMED, MEDLINE, ELSEVIER, and CAPES PERIODIC databases, selecting relevant works for each pharmacophoric group with in vivo antitumor activity in the last 6 years.

RESULTS

In our study, 68 articles that fit the scope were selected and critically analyzed. These articles were organized considering the type of antitumor activity and their year of publication. Some compounds reported here demonstrated potent antitumor activity against several tumor types.

CONCLUSION

This review allowed us to highlight works that reported promising structures for the treatment of various cancer types and also demonstrated that the privileged structures thiazole, isatin and phthalimide are important in the design of new syntheses and molecular optimization of compounds with antitumor activity.

New phenothiazine conjugates as apoptosis inducing agents: Design, synthesis, In-vitro anti-cancer screening and 131I-radiolabeling for in-vivo evaluation

Phenothiazines (PTZs) are a group of compounds characterized by the presence of the 10H-dibenzo-[b,e]-1,4-thiazine system. PTZs used in clinics as antipsychotic drugs with other diverse biological activities. The current aim of the study is to investigate and understand the effect of potent PTZs compounds using a group of In-vitro and In-vivo assays. A total of seventeen novel phenothiazine derivatives have been designed, synthesized, and evaluated primarily in-vitro for their ability to inhibit proliferation activity against NCI-60 cancer cell lines, including several multi-drug resistant (MDR) tumor cell lines. Almost all compounds were active and displayed promising cellular activities with GI50 values in the sub-micromolar range. Four of the most promising derivatives (4b, 4h, 4g and 6e) have been further tested against two selected sensitive cancer cell lines (colon cancer; HCT-116 and breast cancer; MDA-MB231). The apoptosis assay showed that all the selected compounds were able to induce early apoptosis and compound 6e was able to induce additional cellular necrosis. Cell cycle assay showed all selected compounds were able to induce cell cycle arrest at sub-molecular phase of G0-G1 with compound 6e induced cell cycle arrest at G2M in HCT-116 cells. Accordingly, the apoptotic effect of the selected compounds was extensively investigated on genetic level and Casp-3, Casp-9 and Bax gene were up-regulated with down-regulation of Bcl-2 gene suggesting the activation of both intrinsic and extrinsic pathways. In-vivo evaluation of the antitumor activity of compound 4b in solid tumor bearing mice showed promising therapeutic effect with manifestation of dose and time dependent toxic effects at higher doses. For better evaluation of the degree of localization of 4b, its 131I-congener (131I-4b) was injected intravenously in Ehrlich solid tumor bearing mice that showed good localization at tumor site with rapid distribution and clearance from the blood. In-silico study suggested NADPH oxidases (NOXs) as potential molecular target. The compounds introduced in the current study work provided a cutting-edge phenothiazine hybrid scaffold with promising anti-proliferation action that may suggest their anti-cancer activity.

Recent progress in the synthesis of natural product inspired bioactive glycohybrids

Carbohydrates are a basic structural component that are indispensable to all cellular processes. In addition to being employed as chiral starting materials in the synthesis of a variety of natural products, carbohydrates are recognized as naturally occurring molecules having an enormous variety of functional, stereochemical, and structural properties. The understanding and biological roles of carbohydrate derived molecules can be greatly improved by selectively synthesizing functional carbohydrates through incorporating them with privileged scaffolds. For a deeper understanding of their roles and the development of functional materials based on sugar, it is crucial to develop new techniques for efficiently synthesizing, functionalizing, and modifying carbohydrates. Glycohybrids have a wide range of structural and functional characteristics along with protein-carbohydrate interactions that are crucial to mammalian biology and a number of disease states. This review, consisting the literature from January 2017 to July 2023 and provide an overview of recent developments in the chemical synthesis of glycohybrids based on natural product scaffolds of coumarin, quinolone, naphthalene diimide, indole, isatin, naphthoquinone, imidazole and pyrimidine. The biological activity of active glycohybrids are discussed in this review.

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.

Two-carbon tethered artemisinin-isatin hybrids: design, synthesis, anti-breast cancer potential, and in silico study

Eleven two-carbon tethered artemisinin-isatin hybrids (4a-k) were designed, synthesized, and evaluated for their antiproliferative activity against MCF-7, MDA-MB-231, and MDA-MB-231/ADR breast cancer cell lines, as well as cytotoxicity toward MCF-10A cells in this paper. Among them, the representative hybrid 4a (IC50: 2.49-12.6 µM) was superior to artemisinin (IC50: 72.4->100 µM), dihydroartemisinin (IC50: 69.6-89.8 µM), and Adriamycin (IC50: 4.46->100 µM) against the three tested breast cancer cell lines. The structure-activity relationship revealed that the length of the alkyl linker between artemisinin and isatin was critical for the activity, so further structural modification could focus on evaluation of the linker. The in silico studies were used to investigate the mechanism of the most promising hybrid 4a. Target prediction, bioinformatics, molecular docking, and molecular dynamics revealed that the most promising hybrid 4a may exert anti-breast cancer activity by acting on multiple targets such as EGFR, PIK3CA, and MAPK8 and thus participating in multiple tumor-related signaling pathways.

Discovery of isatin-β-methyldithiocarbazate derivatives as New Delhi metallo- β-lactamase-1 (NDM-1) inhibitors against NDM-1 producing clinical isolates

New Delhi metallo-β-lactamase-1 (NDM-1) poses a threat to public health due to its capability to hydrolyze nearly all β-lactam antibiotics, leaving limited treatment options for NDM-1 positive pathogens. Regrettably, there are presently no effective NDM-1 inhibitors in clinical use. This compels us to seek new compounds to combat multi-drug resistant bacterial infections (MDR). In our study, Zndm19 was identified as a new NDM-1 inhibitor through virtual screening and an NDM-1 enzyme activity inhibition assay. Subsequently, we employed the checkerboard method, time-killing assay, and combined disk test to investigate the synergistic bactericidal efficacy of Zndm19 in combination with meropenem (MEM). Meanwhile, molecular docking and site-directed mutagenesis were conducted to uncover the crucial amino acid residues engaged in Zndm19 binding. Finally, we established a mice peritonitis infection model to assess the synergistic effect of Zndm19 and MEM in vivo. Our findings demonstrated that 16 µg/mL of Zndm19 inhibited NDM-1 activity without affecting NDM-1 expression, restoring the bactericidal activity of MEM against NDM-1-positive Escherichia coli in vitro. Furthermore, MET-67, ASP-124, HIS-189, and HIS-250 amino acid residues constituted the active site of Zndm19 in NDM-1. Importantly, this combination therapy exhibited synergistic anti-infection activity in the mice peritonitis infection model, leading to an approximate 60% increase in survival rates and reduction of tissue bacterial load, effectively combating bacterial infection in vivo. In summary, our research validates that the synthetic novel NDM-1 inhibitor Zndm19 holds promise as a drug to treat drug-resistant bacterial infections, especially those harboring NDM-1.

Design, synthesis, molecular docking and DFT studies on novel melatonin and isatin based azole derivatives

In order to address the pressing demand for newer broad-spectrum antifungal medicines with enhanced activity, computer modelling was utilised to rationally develop newer antifungal azole-based drugs. Based on the drug and active sites of the Lanosterol 14 alpha-Demethylases (LAD) of the prominent fungal pathogen Candida albicans interaction, Novel triazole-linked melatonin and isatin derivatives 7a-d and 8a-d were synthesised using bioisosterism. Besides the experimental synthesis and subsequent characterization, the present study focused on obtaining optimised geometries, frequency calculations, and TD-DFT studies of the synthesised molecules. We also performed molecular docking studies to explore the inhibitory ability of the synthesised compounds against the active sites of the Lanosterol 14 alpha-Demethylases (LAD) of the prominent fungal pathogen Candida albicans. The binding interactions resulted in positive findings, demonstrating the involvement of the synthesised compounds in the suppression of fungal growth. Comparative analysis of the binding potential of the synthesised molecules and commercially available drug fluconazole revealed a remarkable note: the docking scores for the designed drugs 7b, 7c, and 8c are much greater than those of the fluconazole molecule. The in silico study of the designed series of drug molecules serves as an important guideline for further exploration in the quest for potent antifungal agents.

Green synthesis, anti-proliferative evaluation, docking, and MD simulations studies of novel 2-piperazinyl quinoxaline derivatives using hercynite sulfaguanidine-SA as a highly efficient and reusable nanocatalyst

In this study, the immobilization of sulfaguanidine-SA on the surface of FeAl2O4 (hercynite) MNPs (magnetic nanoparticles) as a novel acid nanocatalyst has been successfully reported for the synthesis of 2-(piperazin-1-yl) quinoxaline derivatives via a one-pot multiple-component reaction under green conditions. The products were characterized by SEM, TEM, TGA, EDS, BET technique, VSM, and FTIR. This series of novel 2-piperazinyl quinoxaline derivatives containing isatin-based thio/semicarbazones and/or Schiff bases of Metformin were evaluated for anticancer activity against both human ovarian and colon-derived tumor cell lines by MTT colorimetric assay. Although most of the investigated hybrid compounds exhibited excellent anti-proliferative activities and high selectivity index (SI) values, the promising compounds N'-[4-(quinoxaline-2-yl)-piperazine-1-yl]methyl-5-chloro-1-H-indole,2,3-dion-3-metformin 4c and N'-[4-(quinoxaline-2-yl)-piperazine-1-yl]methyl-5-bromo-1-H-indole,2,3-dion-3-metformin 4b proved to be the most potent anti-proliferative agents (IC50 values < 1 μM). Molecular docking and dynamics simulation suggest that these hybrid compounds can be wrapped in the catalytic cavity of c-Kit tyrosine kinase receptor and the binding pocket of P-glycoprotein with high scores. Thus, 2-piperazinyl quinoxaline linked isatin-based N-Mannich bases of metformin and/or thio/semicarbazones might be served as suitable candidates for further investigations to develop a new generation of multi-target cancer chemotherapy agents.

Click synthesis, antimicrobial, DNA photocleavage and computational studies of oxindole-tethered 1H-1,2,3-triazoles

Aim: To obtain new hybrids derived from isatin and triazole. Materials & methods: A series of oxindole-1-H-1,2,3-triazole hybrids (4a-l) were synthesized from 3-sulfenylated N-propargylated oxindoles and organic azides employing Cu(I)-catalyzed azide-alkyne cycloaddition. These compounds were evaluated in vitro for antimicrobial activity by the standard serial dilution method and DNA photocleavage activity. Results: Antimicrobial assay revealed that compounds 4l and 4f exhibited promising efficacy against Candida albicans and Rhizopus oryzae, respectively, with a minimum inhibitory concentration value of 0.0008 μmol/mL. Compounds 4h and 4k completely degraded plasmid DNA. Further molecular docking of compounds with 1KZN (4j and 4k) and 5TZ1 (4h and 4l) revealed good binding interactions. Conclusion: Results of the current research can help in the development of new antimicrobial agents with high efficacy.

Design, synthesis, antitumor evaluation, and molecular docking of novel pyrrolo[2,3-d]pyrimidine as multi-kinase inhibitors

In the last twenty years, protein kinases have been identified as important targets for cancer therapy. In order to prevent unexpected toxicity, medicinal chemists have always focused on discovering selective protein kinase inhibitors. However, cancer is a multifactorial process and its formation and progression depend on different stimuli. Therefore, it is imperative to develop anticancer therapy that targets multiple kinases associated cancer progression. In this research a series of hybrid compounds was designed and synthesized successfully with the aim of producing anticancer activity through the induction of multiple protein kinase inhibition. The designed derivatives comprise isatin and pyrrolo[2,3-d]pyrimidine scaffolds in their structures with a hydrazine linking the two pharmacophores. Antiproliferative and kinase inhibition assays revealed promising anticancer and multi-kinase inhibitory effects of compound 7 with comparable results with the reference standards. Moreover, compound 7 suppressed cell cycle progression and induced apoptosis in HepG2 cells. Finally, molecular docking simulation was performed to investigate the potential types of interactions between the protein kinase enzymes and the designed hybrid compounds. The results of this research indicated the promising anticancer effect of compound 7 through the inhibition of a number of protein kinase receptors and the suppression of cell cycle and the induction of apoptosis.

1-Benzyl-5-bromo-3-hydrazonoindolin-2-ones as Novel Anticancer Agents: Synthesis, Biological Evaluation and Molecular Modeling Insights

Human health is experiencing several obstacles in the modern medical era, particularly cancer. As a result, the cancer therapeutic arsenal should be continually expanded with innovative small molecules that preferentially target tumour cells. In this study, we describe the development of two small molecule series (7a–d and 12a–e) based on the 1-benzyl-5-bromoindolin-2-one scaffold that connected through a hydrazone linker to a 4-arylthiazole (7a–d) or 4-methyl-5-(aryldiazenyl)thiazole (12a–e) moiety. The anticancer activity of all the reported indolin-2-one derivatives was assessed against breast (MCF-7) and lung (A-549) cancer cell lines. The 4-arylthiazole-bearing derivatives 7c and 7d revealed the best anticancer activity toward MCF-7 cells (IC50 = 7.17 ± 0.94 and 2.93 ± 0.47, respectively). Furthermore, the VEGFR-2 inhibitory activity for 7c and 7d was evaluated. Both molecules disclosed good inhibitory activity, and their IC50 values were equal to 0.728 µM and 0.503 µM, respectively. Additionally, the impacts of 7d on the cell cycle phases as well as on the levels of different apoptotic markers (caspase-3, caspase-9, Bax, and Bcl-2) were assessed. Molecular docking and dynamic simulations are carried out to explore the binding mode of 7d within the VEGFR-2 active site.

New 6′-Amino-5′-cyano-2-oxo-1,2-dihydro-1′H-spiro[indole-3,4′-pyridine]-3′-carboxamides: Synthesis, Reactions, Molecular Docking Studies and Biological Activity

The purpose of this work was to prepare new isatin- and monothiomalondiamide-based indole derivatives, as well as to study the properties of the new compounds. The four-component reaction of 5-R-isatins (R = H, CH3), malononitrile, monothiomalonamide (3-amino-3-thioxo- propanamide) and triethylamine in hot EtOH yields a mixture of isomeric triethylammonium 6′-amino-3′-(aminocarbonyl)-5′-cyano-2-oxo-1,2-dihydro-1′H- and 6′-amino-3′-(aminocarbonyl)- 5′-cyano-2-oxo-1,2-dihydro-3′H-spiro[indole-3,4′-pyridine]-2′-thiolates. The reactivity and structure of the products was studied. We found that oxidation of spiro[indole-3,4′-pyridine]-2′-thiolates with DMSO-HCl system produced only acidification products, diastereomeric 6′-amino-5′-cyano-5-methyl-2-oxo-2′-thioxo-1,2,2′,3′-tetrahydro-1′H-spiro-[indole-3,4′-pyridine]- 3′-carboxamides, instead of the expected isothiazolopyridines. The alkylation of the prepared spiro[indole-3,4′-pyridine]-2′-thiolates upon treatment with N-aryl α-chloroacetamides and α-bromoacetophenones proceeds in a regioselective way at the sulfur atom. In the case of α-bromoacetophenones, ring-chain tautomerism was observed for the S-alkylation products. According to NMR data, the compounds consist of a mixture of stereoisomers of 2′-amino-6′-[(2-aryl-2-oxoethyl)thio]-3′-cyano-2-oxo-1′H-spiro[indoline-3,4′-pyridine]-5′-carboxamides and 5′-amino-3′-aryl-6′-cyano-3′-hydroxy-2-oxo-2′,3′-dihydrospiro[indoline-3,7′-thiazolo[3,2-a]pyridine]-8′-carboxamides in various ratios. The structure of the synthesized compounds was confirmed by IR spectroscopy, HRMS, 1H and 13C DEPTQ NMR studies and the results of 2D NMR experiments (1H-13C HSQC, 1H-13C HMBC). Molecular docking studies were performed to investigate suitable binding modes of some new compounds with respect to the transcriptional regulator protein PqsR of Pseudomonas aeruginosa. The docking studies revealed that the compounds have affinity for the bacterial regulator protein PqsR of Pseudomonas aeruginosa with a binding energy in the range of −5.8 to −8.2 kcal/mol. In addition, one of the new compounds, 2′-amino-3′-cyano-5-methyl-2-oxo-6′-{[2-oxo-2-(p-tolylamino)ethyl]thio}-1′H-spiro-[indoline-3,4′-pyridine]-5′-carboxamide, showed in vitro moderate antibacterial effect against Pseudomonas aeruginosa and good antioxidant properties in a test with 1,1-diphenyl-2-picrylhydrazyl radical. Finally, three of the new compounds were recognized as moderately active herbicide safeners with respect to herbicide 2,4-D in the laboratory experiments on sunflower seedlings.

Artemisinin-isatin hybrids tethered via ethylene linker and their anti-lung cancer activity

The synthesized 11 artemisinin-isatin hybrids 5a-c and 6a-h tethered via ethylene linker were assessed for their in vitro antiproliferative activity against A549 and H1299 nonsmall-cell lung cancer cell lines as well as their cytotoxicity towards BEAS-2B human normal lung epithelial cells. The preliminary results showed that hybrids 5a-c and 6a-h did not show any cytotoxicity (IC50 : >100 µM) on BEAS-2B cells, and also possessed potential activity (IC50 : 6.99-76.49 µM) against A549 and H1299 lung cancer cell lines. The representative hybrid 6c (IC50 : 6.99 and 7.57 µM) was far more potent than artemisinin (IC50 : >100 µM) and dihydroartemisinin (IC50 : >100 µM), and was slightly less active than doxorubicin (IC50 : 4.14 and 2.77 µM). Moreover, hybrid 6c also exhibited an excellent safety profile and good selectivity with SI values of >13.21. Therefore, hybrid 6c could serve as a promising candidate for further in vivo evaluations.

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.

Design, Synthesis, and Biological Evaluation of Novel Amyl Ester Tethered Dihydroartemisinin-Isatin Hybrids as Potent Anti-Breast Cancer Agents

A series of novel amyl ester tethered dihydroartemisinin-isatin hybrids 4a-d and 5a-h were designed, synthesized, and evaluated as anti-breast cancer agents. The synthesized hybrids were preliminarily screened against estrogen receptor-positive (MCF-7 and MCF-7/ADR) and triple-negative (MDA-MB-231 and) breast cancer cell lines. Three hybrids 4a,d and 5e not only were more potent than artemisinin and adriamycin against drug-resistant MCF-7/ADR and MDA-MB-231/ADR breast cancer cell lines, but also displayed non-cytotoxicity towards normal MCF-10 A breast cells, and the SI values were >4.15, indicating their excellent selectivity and safety profiles. Thus, hybrids 4a,d and 5e could act as potential anti-breast cancer candidates and were worthy of further preclinical evaluations. Moreover, the structure-activity relationships which may facilitate further rational design of more effective candidates were also enriched.

Photoinduced halogen-bonding enabled synthesis of oxindoles and isoindolinones from aryl iodides

We report the use of halogen bonding (XB) for the generation of aryl radicals from aryl halides under blue light irradiation and applied it in radical generation/1,5-hydrogen-atom transfer/radical cyclization cascade reactions for the synthesis of oxindoles and isoindolinones. On the basis of experimental studies, we propose that DBU can serve as a suitable XB acceptor with aryl halides for the formation of a photoactive electron donor and acceptor complex.

Design, synthesis, and in vitro cytotoxicity evaluation of novel dihydroartemisinin-isatin hybrids tethered via different length of esters as potential anti-breast cancer agents

In the present work, we reported the design, synthesis, and in vitro cytotoxicity evaluation of novel dihydroartemisinin-isatin hybrids tethered via different length of esters against MCF-7, MDA-MB-231, MCF-7/ADR and MDA-MB-231/ADR breast cancer cell lines. The preliminary results showed that the majority of the hybrids exhibited good anti-breast cancer cell activity. In particular, hybrids 7 g and 7n not only were more potent than ART, DHA and ADR against the four tested breast cancer cell lines, but also were non-toxic towards normal MCF-10A breast cells. The selectivity index values of hybrids 7 g and 7n were > 12.83 and > 25.97 respectively, revealing their excellent safety and selectivity profiles. The drug-resistant index values of hybrids 7 g and 7n were in a range of 0.33 to 1.12, implying that these hybrids had the potential to overcome drug resistance. Accordingly, hybrids 7 g and 7n could be considered as potential lead molecules for the development of novel anti-breast cancer agents with minimal untoward events to normal human cells. The structure-activity relationships indicated that the length of ester likner between DHA and isatin as well as substituents at C-3 and C-5 positions of isatin moiety had great impact on the activity.

Development and evaluation of novel artemisinin-isatin hybrids with potential anti-leukemic cytotoxicity

Twenty-one novel ester tethered artemisinin-isatin hybrids were designed, synthesized and screened against human myeloid leukemia cell lines (K562 and K562/ADR), human acute lymphoblastic leukemia cell line (CCRF-CEM) as well as normal human peripheral blood mononuclear cells (PBMCs) for their cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The structure-activity relationships (SARs) were also discussed to facilitate further rational design of more effective candidates. The preliminary results showed that most of the ester tethered artemisinin-isatin hybrids (IC₅₀: 0.32-29.35 µM) exhibited promising activity against CCRF-CEM cells, and some of them (IC₅₀: 1.23-49.84 µM) were also active against K562 and K562/ADR human myeloid leukemia cell lines. Among them, hybrid 7d (IC₅₀: 0.32, 2.67 and 1.23 µM) not only possessed profound activity against the three tested leukemia cell lines and excellent safety and selectivity profiles, but also showed promising pharmacokinetic properties. Accordingly, hybrid 7d could be considered as a potential lead molecule for the development of novel anti-leukemic agents with minimal untoward events to normal human cells.

Design, synthesis and anti-breast cancer properties of butyric ester tethered dihydroartemisinin-isatin hybrids

Fifteen novel butyric ester tethered dihydroartemisinin-isatin hybrids 4a-d and 5a-k were designed, synthesized, and evaluated for cytotoxicity against four human breast cancer cell lines, including MCF-7, MDA-MB-231, MCF-7/ADR and MDA-MB-231/ADR using the MTT method. A significant part of them were active against the four tested cancer cell lines, and the representative hybrid 5b (IC₅₀: 1.27 µM) was 14.88 -> 78.74 times more active than adriamycin (IC₅₀: 18.90 µM), DHA (IC₅₀: 28.28 µM) and ART (IC₅₀: > 100 µM) against MCF-7 breast cancer cells, whereas hybrid 5c (IC₅₀: 2.39 and 3.95 µM) was superior to adriamycin (IC₅₀: 3.38 and >100 µM), DHA (IC₅₀: 48.80 and 82.78 µM) and ART (IC₅₀: >100 and >100 µM) against MDA-MB-231 and MDA-MB-231/ADR breast cancer cell lines. Moreover, the selected hybrids (IC₅₀: >100 µM) displayed non-cytotoxicity towards normal MCF-10A breast cells, and the SI values of hybrids 5b,c were >78.74 and >41.84 respectively, demonstrating their excellent selectivity and safety profiles. Accordingly, hybrids 5b,c could serve as promising anti-breast cancer candidates and deserved further preclinical evaluations.

New Insights into the Structural Requirements of Isatin-Derived Pro-Apoptotic Agents against Acute Myeloid Leukemia

Searching for bioactive compounds within the huge chemical space is like trying to find a needle in a haystack. Isatin is a unique natural compound which is endowed with different bio-pertinent activities, especially in cancer therapy. Herein, we envisaged that adopting a hybrid strategy of isatin and α,β-unsaturated ketone would afford new chemical entities with strong chemotherapeutic potential. Of interest, compounds 5b and 5g demonstrated significant antiproliferative activities against different cancer genotypes according to NCI-60 screening. Concomitantly, their IC₅₀ against HL-60 cells were 0.38 ± 0.08 and 0.57 ± 0.05 µM, respectively, demonstrating remarkable apoptosis and moderate cell cycle arrest at G1 phase. Intriguingly, an impressive safety profile for 5b was reflected by a 37.2 times selectivity against HL-60 over PBMC from a healthy donor. This provoked us to further explore their mechanism of action by in vitro and in silico tools. Conclusively, 5b and 5g stand out as strong chemotherapeutic agents that hold clinical promise against acute myeloid leukemia.

Synthesis, Biocidal and Antibiofilm Activities of New Isatin-Quinoline Conjugates against Multidrug-Resistant Bacterial Pathogens along with Their In Silico Screening

Isatin-quinoline conjugates 10a-f and 11a-f were assembled by the reaction of N-(bromobutyl) isatin derivatives 3a, b with aminoquinolines 6a-c and their corresponding hydrazinyl 9a-c in good yields. The structures of the resulting conjugates were established by spectroscopic tools and showed data consistent with the proposed structures. In vitro antibacterial activity against different bacterial strains was evaluated. All tested conjugates showed significant biocidal activity with lower MIC than the first line drugs chloramphenicol and ampicillin. Conjugates 10a, 10b and 10f displayed the most potent activity against all clinical isolates. The antibiofilm activity for all tested conjugates was screened against the reference drug vancomycin using the MRSA strain. The results revealed that all conjugates had an inhibitory activity against biofilm formation and conjugate. Conjugate 11a showed 83.60% inhibition at 10 mg/mL. In addition, TEM studies were used to prove the mechanism of antibacterial action of conjugates 10a and 11a against (MRSA). Modeling procedures were performed on 10a-f and 11a-f and interestingly the results were nearly consistent with the biological activities. In addition, in silico pharmacokinetic evaluation was performed and revealed that the synthesized compounds 10a-f and 11a-f were considered drug-like molecules with promising bioavailability and high GI absorption. The results confirmed that the title compounds caused the disruption of bacterial cell membranes and could be used as potential leads for the further development and optimization of antibacterial agents.

Palladium-Catalyzed Domino Carbopalladation/Carbonylative Cyclization: Synthesis of Heterocycles bearing Oxindoles and 3-Acylbenzofuran/3-Acylindole Moieties

A novel and straightforward methodology for palladium-catalyzed carbopalladation-initiated domino carbonylative cyclization to construct bisheterocycles has been established. With TFBen as an efficient and convenient CO source, the protocol is capable of generating oxindole and 3-acylbenzofuran/3-acylindole moieties from the corresponding N-(o-iodoaryl)acrylamides and o-alkynylphenols/o-alkynylanilines with the formation of three C-C bonds and one C-O/C-N bond in a single one-step operation. A wide range of bisheterocycles bearing oxindoles and 3-acylbenzofurans/3-acylindoles were prepared in moderate to excellent yields with good functional group tolerance.

Crystal structure and Hirshfeld surface analysis of N-(2,6-di-methyl-phen-yl)-2-[3-hy-droxy-2-oxo-3-(2-oxoprop-yl)indolin-1-yl]acetamide

The cup-shaped conformation of the title mol-ecule, C21H22N2O4, is largely determined by an intra-molecular N-H⋯O hydrogen bond. In the crystal, double layers of mol-ecules are formed by O-H⋯O and C-H⋯O hydrogen bonds. A Hirshfeld surface analysis was performed, which confirms the regions that are active for inter-molecular inter-actions.

N-1,2,3-Triazole-isatin derivatives: anti-proliferation effects and target identification in solid tumour cell lines

Molecular hybridization approaches have become an important strategy in medicinal chemistry, and to this end, we have developed a series of novel N-1,2,3-triazole-isatin hybrids that are promising as tumour anti-proliferative agents. Our isatin hybrids presented high cytotoxic activity against colon cancer cell line SW480, lung adenocarcinoma cell line A549, as well as breast cancer cell lines MCF7 and MDA-MB-231. All tested compounds demonstrated better anti-proliferation (to 1-order of magnitude) than the cis-platin (CDDP) benchmark. In order to explore potential biological targets for these compounds, we used information from previous screenings and identified as putative targets the histone acetyltransferase P-300 (EP300) and the acyl-protein thioesterase 2 (LYPLA2), both known to be involved in epigenetic regulation. Advantageous pharmacological properties were predicted for these compounds such as good total surface area of binding to aromatic and hydrophobic units in the enzyme active site. In addition, we found down-regulation of LYPLA2 and EP300 in both the MCF7 and MDA-MB-231 breast cancer cells treated with our inhibitors, but no significant effect was detected in normal breast cells MCF10A. We also observed upregulation of EP300 mRNA expression in the MCF10A cell line for some of these compounds and the same effect for LYPLA2 mRNA in MCF7 for one of our compounds. These results suggest an effect at the transcriptional regulation level and associated with oncological contexts.

Design, synthesis, in silico studies, and antiproliferative evaluations of novel indolin-2-one derivatives containing 3-hydroxy-4-pyridinone fragment

Keeping in view the pharmacological properties of indolinones as promising scaffold as kinase inhibitors, herein, a novel series of 3-hydrazonoindolin-2-one derivatives bearing 3-hydroxy-4-pyridinone moiety were synthesized, studied by molecular docking, and fully characterized by spectroscopic techniques. All the prepared compounds were evaluated for their cytotoxicity attributes against a panel of tumor cell lines, including non-small cell lung cancer (A549), breast carcinoma (MCF-7), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML). They displayed moderate to promising antiproliferative effects toward A549 and MCF-7 cells but remarkable results against AML and CML. Especially, compound 10k was found to be more potent against AML (EC₅₀ = 0.69 μM) compare to the other halogen-substituted derivatives. FMS-like tyrosine kinase 3 (FLT3) is known to be expressed in AML cancer cells. The molecular docking studies demonstrated that our prepared compounds were potentially bound to AML active site through essential H-bond and other vital interactions with critical binding residues.

Isatin thiazoles as antidiabetic: Synthesis, in vitro enzyme inhibitory activities, kinetics, and in silico studies

Diabetes mellitus is one of the most prevalent diseases nowadays. Several marketed drugs are available for the cure and treatment of diabetes, but there is still a dire need of introducing compatible drug molecules with lesser side effects. The current study is based on the synthesis of isatin thiazole derivatives 4-30 via the Hantzsch reaction. The synthetic compounds were characterized using different spectroscopic techniques and evaluated for their α-amylase and α-glucosidase inhibition potential. Of 27 isatin thiazoles, five (4, 5, 10, 12, and 16) displayed good activities against the α-amylase enzyme with IC50 values in the range of 22.22 ± 0.02-27.01 ± 0.06 µM, and for α-glucosidase, the IC50 values of these compounds were in the range of 20.76 ± 0.17-27.76 ± 0.17 µM, respectively. The binding interactions of the active molecules within the active site of enzymes were studied with the help of molecular docking studies. In addition, kinetic studies were carried out to examine the mechanism of action of the synthetic molecules as well. Compounds 3a, 4, 5, 10, 12, and 16 were also examined for their cytotoxic effect and were found to be noncytotoxic. Thus, several molecules were identified as good antihyperglycemic agents, which can be further modified to enhance inhibition ability and to find the lead molecule that can act as a potential antidiabetic agent.

Isatin Counteracts Diethylnitrosamine/2-Acetylaminofluorene-Induced Hepatocarcinogenesis in Male Wistar Rats by Upregulating Anti-Inflammatory, Antioxidant, and Detoxification Pathways

Hepatocellular carcinoma (HCC) represents around 85% of all known types of liver cancers and is estimated to be the fifth most common cause of cancer-related death worldwide. The current study assessed the preventive efficacy of isatin on diethylnitrosamine (DENA)/2-acetylaminofluorene (2-AAF)-induced hepatocarcinogenesis in male Wistar rats and investigated the underlying cellular and molecular mechanisms. HCC was initiated by intraperitoneal injection of DENA (150 mg/kg/week) for two weeks, followed by oral 2-AAF (20 mg/kg) every other day for three successive weeks. Oral isatin or vehicle (control) was administered at 25 mg/kg for 20 weeks during and following HCC induction. Isatin ameliorated the deleterious effects of DENA/2-AAF on liver function as evidenced by reduced serum levels of AST, ALT, total bilirubin, albumin, and liver tumor biomarkers (CA19.9 and AFP) compared to control DENA/2-AAF-treated rats. Histopathological evaluations demonstrated that isatin-mediated protection against hepatocarcinogenesis was accompanied by a decline in hepatic lipid peroxidation, a marker of oxidative stress, and enhanced antioxidant capacity, as evidenced by increased glutathione and superoxide dismutase expression. Isatin treatment also upregulated expression of the major stress-response transcription factor Nrf2 and the detoxifying enzymes NAD(P)H quinine oxidoreductase and glutathione-S-transferase alpha 2 and downregulated expression of the proliferation marker Ki67. Moreover, isatin significantly reduced the DENA/2-AAF-induced decrease in hepatic expression of anti-apoptotic Bcl2 and the DENA/2-AAF-induced increases in pro-inflammatory and pro-apoptotic factors (TNF-α, NF-κB p50, NF-κB p65, p53, and caspase 3). Thus, it can be concluded that isatin may protect against chemically induced hepatocarcinogenesis by enhancing cellular antioxidant, anti-inflammatory, and detoxification mechanisms, in part through upregulation of the Nrf2 signaling pathway.

Anticancer Effects with Molecular Docking Confirmation of Newly Synthesized Isatin Sulfonamide Molecular Hybrid Derivatives against Hepatic Cancer Cell Lines

The current study investigated the cytotoxic effect of ten sulfonamide-derived isatins, following molecular hybridization, based on the association principles, on hepatocellular carcinoma (HCC) HepG2 and Huh7 cell lines, compared for safety using human normal retina pigmented epithelial (RPE-1) cells. The ten compounds showed variable in vitro cytotoxicity on HepG2 and Huh7 cells, using the MTT assay. Four compounds (4/10) were highly cytotoxic to both HepG2 and HuH7. However, only 3 of these 4 were of the highest safety margin on RPE-1 cells in vitro and in the in vivo acute (14-day) oral toxicity study. These later, superior three compounds' structures are 3-hydroxy-3-(2-oxo-2-(p-tolyl)ethyl)-5-(piperidin-1-ylsulfonyl)indolin-2-one (3a), N-(4-(2-(2-oxo-5-(piperidin-1-ylsulfonyl)indolin-3-ylidene)acetyl)phenyl)acetamide (4b), and N-(3-(2-(2-oxo-5-(piperidin-1-ylsulfonyl)indolin-3-ylidene)acetyl)phenyl)acetamide (4c). The half-maximal inhibitory concentration (IC50) of the tested compounds (3a, 4b, and 4c) on HepG2 cells were approximately 16.8, 44.7, and 39.7 μM, respectively. The 3a, 4b, and 4c compounds significantly decreased the angiogenic marker epithelial growth factor receptor (EGFR) level and that was further confirmed via molecular docking inside the EFGR active site (PDB: 1M17). The binding free energies ranged between -19.21 and -21.74 Kcal/mol compared to Erlotinib (-25.65 Kcal/mol). The most promising compounds, 3a, 4b, and 4c, showed variable anticancer potential on "hallmarks of cancer", significant cytotoxicity, and apoptotic anti-angiogenic and anti-invasive effects, manifested as suppression of Bcl-2, urokinase plasminogen activation, and heparanase expression in HepG2-treated cells' lysate, compared to non-treated HepG2 cells. In conclusion, compound "3a" is highly comparable to doxorubicin regarding cell cycle arrest at G2/M, the pre-G0 phases and early and late apoptosis induction and is comparable to Erlotinib regarding binding to EGFR active site. Therefore, the current study could suggest that compound "3a" is, hopefully, the most safe and active synthesized isatin sulfonamide derivative for HCC management.

Therapeutic Outcomes of Isatin and Its Derivatives against Multiple Diseases: Recent Developments in Drug Discovery

Isatin (1H indole 2, 3-dione) is a heterocyclic, endogenous lead molecule recognized in humans and different plants. The isatin nucleus and its derivatives are owed the attention of researchers due to their diverse pharmacological activities such as anticancer, anti-TB, antifungal, antimicrobial, antioxidant, anti-inflammatory, anticonvulsant, anti-HIV, and so on. Many research chemists take advantage of the gentle structure of isatins, such as NH at position 1 and carbonyl functions at positions 2 and 3, for designing biologically active analogues via different approaches. Literature surveys based on reported preclinical, clinical, and patented details confirm the multitarget profile of isatin analogues and thus their importance in the field of medicinal chemistry as a potent chemotherapeutic agent. This review represents the recent development of isatin analogues possessing potential pharmacological action in the years 2016-2020. The structure-activity relationship is also discussed to provide a pharmacophoric pattern that may contribute in the future to the design and synthesis of potent and less toxic therapeutics.