Design, synthesis, molecular docking and biological activity evaluation of some novel indole derivatives as potent anticancer active agents and apoptosis inducers

Mechanistic insight and structure activity relationship of isatin-based derivatives in development of anti-breast cancer agents

Breast cancer is most common in women and most difficult to manage that causes highest mortality and morbidity among all diseases and posing significant threat to mankind as well as burden on healthcare system. In 2020, 2.3 million women were diagnosed with breast cancer and it was responsible for 685,000 deaths globally, suggesting the severity of this disease. Apart from that, relapsing of cases and resistance among available anticancer drugs along with associated side effects making the situation even worse. Therefore, it is a global emergency to develop potent and safer antibreast cancer agents. Isatin is most versatile and flying one nucleus which is an integral competent and various anticancer agent in clinical practice and widely used by various research groups around the globe for development of novel, potent, and safer antibreast cancer agents. This review will shed light on the structural insights and antiproliferative potential of various isatin-based derivatives developed for targeting breast cancer in last three decades that will help researchers in design and development of novel, potent, and safer isatin-based antibreast cancer agents.

Utilising UPLC-QTOF-MS/MS to determine the phytochemical profile and in vitro cytotoxic potential of Ziziphora capitata L. with molecular docking simulation

Ziziphora capitata (Lamiaceae family) aerial parts extract contains 57 metabolites, including flavonoids, phenolic acids, anthocyanins, and coumarins, as assessed by UPLC-QTOF-MS/MS. Successive extracts (hexane, chloroform, ethyl acetate, ethanol 95%, and water) were tested in vitro cytotoxic activity against HepG-2, MCF-7, HCT-116, A549, and PC3 cell lines. The results revealed that hexane extract exhibited the most potent cytotoxic activity among PC3 and A549 cell lines, IC50 = 47.1 ± 1.75 and 49.2 ± 1.08 µg/mL compared to Vinblastine IC50 = 42.47 ± 1.95 and 24.64 ± 1.18 µg/mL, respectively, and had a moderate impact on the remaining cell lines. Moreover, the chloroform and ethyl acetate extracts exhibited moderate affinity among all tested cell lines. Furthermore, the total phenolic and flavonoid contents were assessed. The molecular docking simulation was performed inside the effective sites of VEGFR-2 and TS as anticancer targets for the top ten phytochemicals. The results showed higher binding energy values for VEGFR-2 than for TS compared to vinblastine and co-crystallized ligands.

Role of heterocycles in inhibition of VEGFR-2 - a recent update (2019-2022)

The literature reveals that oncogenic protein kinase inhibition has been proved to be a successful anticancer approach. The vascular endothelial growth factor receptor (VEGFR) kinase plays an important role in angiogenesis and metastasis. VEGFR-2 has an upper hand in the angiogenesis process. Vascular endothelial growth factor activates VEGFR-2 which initiates tumor angiogenesis. In addition, VEGFRs are associated with numerous other diseases. Hence, inhibition of VEGFRs is an attractive approach for cancer treatment. In view of this, researchers designed and discovered small molecular heterocycle-based VEGFR-2 inhibitors and some of them have been approved by the Food and Drug Administration (FDA). However, these VEGFR-2 inhibitors pose adverse side effects such as cardiovascular problems, diarrhea, and renal function impairment. Research indicates that combination of certain pharmacophores exhibits excellent VEGFR inhibitory activity. In particular, combination of heterocycles paved the way to efficient VEGFR inhibitors. In this review, the research focusing on VEGFR inhibitory activity has been discussed along with the structure-activity relationship. In addition to emphasizing the most potent molecule among the set of designed molecules, structural features responsible for such an activity are described. This review may aid in designing potent VEGFR inhibitors.

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.

Antimicrobial Evaluation of Sulfonamides after Coupling with Thienopyrimidine Coplanar Structure

This work describes the design and synthesis of three series of hybrids of thienopyrimidines and sulfonamides. Dihydrofolate reductase enzyme was selected as a target for the in-silico screening of the synthesized thienopyrimidine-sulfonamide hybrid as an antibacterial, while squalene epoxidase was selected as an antifungal target protein. All screened compounds showed promising binding affinity ranges, with perfect fitting not exceeding 1.9 Å. The synthesized compounds were tested for their antimicrobial activity using agar well diffusion and minimum inhibitory concentration tests against six bacterial strains in addition to two Candida strains. Compounds 8iii and 12ii showed varying degrees of inhibition against Staphylococcus aureus and Escherichia coli bacterial strains, whereas the best antifungal activity against Candida was displayed by compound 8iii. Compound 12ii, the cyclohexathienopyrimidine coupled with sulfadiazine at position 3, has the best antibacterial activity, which is consistent with molecular docking results at the active site of the oxidoreductase protein. Interestingly, compound 12ii also has the highest docking binding energy at the antifungal squalene epoxidase active site. Investigating the physicochemical properties of the synthesized hybrids revealed their high tolerability with cell membranes, and moderate to poor oral bioavailability, and that all are drug-like candidates, among which 4i, the cyclohexathieno[2,3-d] pyrimidine core with sulphaguanidine incorporated at position 4, recorded the best score (1.58).

Highly efficient, catalyst-free, one-pot sequential four-component synthesis of novel spiroindolinone-pyrazole scaffolds as anti-Alzheimer agents: in silico study and biological screening

Alzheimer's disease is a neurodegenerative disorder that impacts memory, thinking, and behavior, and currently, there is no effective cure available for its treatment. This study explored a one-pot strategy for synthesizing spiroindolinone-pyrazole derivatives through a sequential four-component condensation reaction. These derivatives were further investigated for their potential as anti-Alzheimer's disease agents. The developed synthetic procedure provides remarkable advantages, including a clean reaction profile, abundant starting materials, operational simplicity, and easy purification without traditional methods with good to excellent yields (84-96%). Next, the biological potencies of the newly synthesized spiroindolinone-pyrazole derivatives against AChE and BChE as Alzheimer's disease-related targets were determined. Also, the kinetic study and cytotoxicity of the most potent derivative were investigated. Furthermore, molecular docking and molecular dynamics evaluations were performed employing in silico tools to investigate the interaction, orientation, and conformation of the potent analog over the active site of the enzyme.

Exploring novel derivatives of isatin-based Schiff bases as multi-target agents: design, synthesis, in vitro biological evaluation, and in silico ADMET analysis with molecular modeling simulations

Recently, scientists developed a powerful strategy called "one drug-multiple targets" to discover vital and unique therapies to fight the most challenging diseases. Novel derivatives of isatin-based Schiff bases 2-7 have been synthesized by the reaction of 3-hydrazino-isatin (1) with aryl aldehydes, hetero-aryl aldehydes, and dialdehydes. The structure of the synthesized derivatives was proved by physical and spectral analysis. Additionally, in vitro biological studies were performed, including antioxidant, anti-diabetic, anti-Alzheimer, and anti-arthritic activities. The four derivatives 3b, 5a, 5b, and 5c possess the highest activities. Among the four potent derivatives, compound 5a exhibited the highest antioxidant (TAC = 68.02 ± 0.15 mg gallic acid per g; IRP = 50.39 ± 0.11) and scavenging activities (ABTS = 53.98 ± 0.12% and DPPH = 8.65 ± 0.02 μg mL^-1). Furthermore, compound 5a exhibited an α-amylase inhibitory percentage of 57.64 ± 0.13% near the acarbose (ACA = 69.11 ± 0.15%) and displayed inhibitor activity of the acetylcholinesterase (AChE) enzyme = 36.38 ± 0.08%. Moreover, our work extended to determining the anti-arthritic effect, and compound 5a revealed good inhibitor activities with very close values for proteinase denaturation (PDI) = 39.59 ± 0.09% and proteinase inhibition (PI) = 36.39 ± 0.08%, compared to diclofenac sodium PDI = 49.33 ± 0.11% and PI = 41.88 ± 0.09%. Additionally, the quantum chemical calculations, including HOMO, LUMO, and energy band gap were determined, and in silico ADMET properties were predicted, and their probability was recorded. Finally, molecular docking simulations were performed inside α-amylase and acetylcholinesterase enzymes.

Structure activity relationship (SAR) and anticancer activity of pyrrolidine derivatives: Recent developments and future prospects (A review)

Pyrrolidine molecules are a significant class of synthetic and natural plant metabolites, which show the diversity of pharmacological activities. An extensive variety of synthetic pyrrolidine compounds with numerous derivatization like spirooxindole, thiazole, metal complexes, coumarin, etc have revealed significant anticancer activity. Pyrrolidine molecules are found not only as potential anticancer candidates but also retain the lowest side effects. Depending upon the diverse substitution patterns of the derivatives, these molecules have demonstrated an incredible ability to regulate the various targets to give excellent anti-proliferative activities. Taking these into consideration, efforts have been taken by the scientific fraternity to design and develop a potent anticancer scaffold with negligible side effects. In the present review, we cover the latest advancements in the synthesis of pyrrolidine molecules which have promising anticancer activity toward numerous cancer cell lines. Additionally, it also highlights the effectiveness of derivatives via elucidation of Structural-Activity-Relationship (SAR) which is discussed in detail.

Spirooxindole: A Versatile Biologically Active Heterocyclic Scaffold

Spirooxindoles occupy an important place in heterocyclic chemistry. Many natural spirooxindole-containing compounds have been identified as bio-promising agents. Synthetic analogs have also been synthesized utilizing different pathways. The present article summarizes the recent development of both natural and synthetic spirooxindole-containing compounds prepared from isatin or its derivatives reported in the last five years. The spirooxindoles are categorized based on their mentioned biological properties.

Evaluation of the anti-proliferative activity of 2-oxo-pyridine and 1′H-spiro-pyridine derivatives as a new class of EGFRWt and VEGFR-2 inhibitors with apoptotic inducers†

Developing new agents for cancer treatment remains a top priority because it is one of the deadliest worldwide. A new series of 2-oxo-pyridine and 1′H-spiro-pyridine derivatives were designed and synthesized based on an N-(ethyl benzoate) moiety. The structure of the designed derivatives was confirmed by different spectroscopic techniques (FT-IR and NMR) and elemental analysis and then evaluated as antiproliferative against HepG-2 and Caco-2 cell lines compared with Doxorubicin. The spiro-pyridine derivatives 5, 7, and 8 exhibited a remarkably higher activity against Caco-2 cell lines than that of other derivatives. Additionally, these derivatives exhibited activation in the Bax and suppressed Bcl-2 expression with variable degrees. Interestingly, compound 7 showed the lowest cytotoxicity value on Caco-2 cells (IC₅₀ = 7.83 ± 0.50 μM) compared with Doxorubicin (IC₅₀ = 12.49 ± 1.10 μM). Additionally, this compound showed activation of the Bax gene (7.508-fold) and suppressed Bcl-2 (0.194-fold) compared to untreated Caco-2 cells, as revealed by the qRT-PCR technique. Moreover, compound 7 could inhibit EGFR and VEGFR-2 with sub-micromole values of 0.124 μM and 0.221 μM compared with Erlotinib (IC₅₀ = 0.033 μM) and Sorafenib (IC₅₀ = 0.043 μM), respectively. Further, cell cycle and apoptosis analysis demonstrated that compound 7 promoted apoptosis by increasing the apoptosis rate from 1.92 to 42.35% and the S cell accumulation ratio from 31.18 to 42.07% compared to untreated Caco-2 cells. Finally, the most active compound 7 showed good drug-likeness and toxicity profiles. Besides, molecular docking studies were performed to determine the binding mode, which is in agreement with the in vitro results.

Design and synthesis a novel of 2-oxo-pyridine and 1′H-spiro-pyridine derivatives as a new apoptotic inducers agents.

Therapeutic strategies for Covid-19 based on molecular docking and dynamic studies to the ACE-2 receptors, Furin, and viral spike proteins

SARS-CoV-2 is a pandemic virus that caused infections and deaths in many world countries, including the Middle East. The virus-infected human cells by binding via ACE-2 receptor through the Spike protein of the virus with Furin's help causing cell membrane fusion leading to Covid-19-cell entry. No registered drugs or vaccines are triggering this pandemic viral disease yet. Our present work is based on molecular docking and dynamics simulation that performed to spike protein-ACE-2 interface complex, ACE-2 receptor, Spike protein (RBD), and Furin as targets for new small molecules. These drugs target new potential therapies to show their probabilities toward the active sites of mentioned proteins, strongly causing inhibition and/or potential therapy for covid-19. All target proteins were estimated against new target compounds under clinical trials and repurposing drugs currently present. Possibilities of those molecules and potential therapeutics acting on a certain target were predicted. MD simulations over 200 ns with molecular mechanics-generalized Born surface area (MMGBSA) binding energy calculations were performed. The structural and energetic analyses demonstrated the stability of the ligands-M^Pros complex. Our present work will introduce new visions of some biologically active molecules for further studies in-vitro and in-vivo for Covid-19, repurposing of these molecules should be taking place under clinical works and offering different strategies for drugs repurposing against Covid-19 diseases.Communicated by Ramaswamy H. Sarma.

Novel 3-Methyleneisoindolinones Diversified via Intramolecular Heck Cyclization Induce Oxidative Stress, Decrease Mitochondrial Membrane Potential, Disrupt Cell Cycle, and Induce Apoptosis in Head and Neck Squamous Cell Carcinoma Cells

Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent cancer in the world and the most prevalent cancer of developing countries. Increased disease burden and a smaller number of approved targeted therapies are a growing concern worldwide. Isoindolinone motifs have been a central part of many pharmacological compounds, and their derivatives possess substantial anticancer potential. However, their anticancer potential against HNSCC has not been well investigated. In the current study, a series of 3-methyleneisoindolinones have been designed and synthesized and their late-stage intramolecular Heck cyclization was achieved to evaluate their anticancer potential against HNSCC cells. Additionally, in silico ADME profiling of synthesized compounds revealed their drug-likeness properties as potential drug candidates. Among the synthesized compounds, 3-bromo-5-methylpyridin-2-yl-3-methyleneisoindolin-1-one, i.e., 3n, with a pyridyl unit exhibited the most significant cytotoxicity against HNSCC cells. The cytotoxic potential of synthesized compounds varied depending on the nature of substituents present and has been well established with structure-activity relationship studies. Further, flow cytometric analysis showed that 3f, 3h, and 3n triggered intracellular oxidative stress, disrupted mitochondrial membrane potential, and interrupted the cell cycle of HNSCC cells in the S-phase and sub-G1 phase. Further, 3f, 3h, and 3n also exhibited pro-apoptotic potential and induced cellular apoptosis in the HNSCC cells. Overall, the findings of this study attributed 3-methyleneisoindolinone chemistry and efficacy evaluation and corroborated their anticancer potential against HNSCC. It will pave the way to further design and optimize novel 3-methyleneisoindolinone as effective antitumor agents, which may provide effective treatment modalities against HNSCC.

Design, Synthesis, Anticancer Activity and Molecular Docking of New 1,2,3-Triazole-Based Glycosides Bearing 1,3,4-Thiadiazolyl, Indolyl and Arylacetamide Scaffolds

New 1,3,4-thiadiazole thioglycosides linked to a substituted arylidine system were synthesized via heterocyclization via click 1,3-dipolar cycloaddition. The click strategy was used for the synthesis of new 1,3,4-thiadiazole and 1,2,3-triazole hybrid glycoside-based indolyl systems as novel hybrid molecules by reacting azide derivatives with the corresponding acetylated glycosyl terminal acetylenes. The cytotoxic activities of the compounds were studied against HCT-116 (human colorectal carcinoma) and MCF-7 (human breast adenocarcinoma) cell lines using the MTT assay. The results showed that the key thiadiazolethione compounds, the triazole glycosides linked to p-methoxyarylidine derivatives and the free hydroxyl glycoside had potent activity comparable to the reference drug, doxorubicin, against MCF-7 human cancer cells. Docking simulation studies were performed to check the binding patterns of the synthesized compounds. Enzyme inhibition assay studies were also conducted for the epidermal growth factor receptor (EGFR), and the results explained the activity of a number of derivatives.

Design, synthesis, and biological evaluation of new celecoxib analogs as apoptosis inducers and cyclooxygenase-2 inhibitors

Series of new celecoxib analogs were synthesized to assess their anticancer activity against the MCF-7 cell line. Four compounds, 3a, 3c, 5b, and 5c, showed 1.4-9.2-fold more potent anticancer activity than celecoxib. The antiproliferative activity of the most potent compounds, 3c, 5b, and 5c, seems to be associated well with their ability to induce apoptosis in MCF-7 cells (18-24-fold). This evidence was supported by an increase in the expression of the tumor suppressor gene p53 (4-6-fold), the elevation in the Bax/BCL-2 ratio, and a significant increase in the level of active caspase-7 (4-7-fold). Moreover, compounds 3c and 5c showed significant cyclooxygenase-2 (COX-2) inhibitory activity. They were also docked into the crystal structure of the COX-2 enzyme (PDB ID: 3LN1) to understand their mode of binding.

Synthesis, biological evaluation, and in silico studies of indole-tethered pyrazoline derivatives as anticancer agents targeting topoisomerase IIα

We herein report a new series of indole-tethered pyrazoline derivatives as potent anticancer agents. A total of 12 compounds were designed and synthesized by conventional as well as microwave-irradiated synthesis methods. The latter method results in a significant reduction in the duration of reaction along with improved yields. All synthesized derivatives (7a-7l) were evaluated for their cytotoxic activity against A431, HeLa, and MDAMB-231 cell lines. Compounds 7a and 7b were found most potent in the series and demonstrated an IC₅₀ value of 3.17 and 5.16 µM against the A431 cell line, respectively, compared to the standard drug doxorubicin. Compounds 7a and 7b significantly suppress colony formation, migration, and S phase cell cycle arrest of A431 cells. Furthermore, compound 7a regulated the expression of apoptotic proteins causing the downregulation of procaspase 3/9, antiapoptotic protein Bcl-xL, and upregulation of proapoptotic protein Bax in a dose-dependent manner. Topoisomerase enzyme inhibition assay confirmed that compounds 7a and 7b can significantly inhibit topoisomerase IIα. In vivo oral acute toxicity of compounds 7a and 7b revealed that both compounds are safe compared to doxorubicin; cardiomyopathy studies showed normal architecture of cardiomyocytes and myofibrils. In addition, molecular docking studies revealed the possible interaction of compounds 7a and 7b within the active binding site of the topoisomerase enzyme. The 100 ns molecular dynamic simulation of compounds 7a and 7b proved that both compounds validate all screening parameters.

Novel etodolac derivatives as eukaryotic elongation factor 2 kinase (eEF2K) inhibitors for targeted cancer therapy

Eukaryotic elongation factor 2 kinase (eEF2K) has been shown to be an important molecular driver of tumorigenesis and validated as a potential novel molecular target in various solid cancers including triple negative breast cancer (TNBC). Therefore, there has been significant interest in identifying novel inhibitors of eEF2K for the development of targeted therapeutics and clinical translation. Herein, we investigated the effects of indole ring containing derivatives of etodolac, a nonsteroidal anti-inflammatory (NSAID) drug, as potential eEF2K inhibitors and we designed and synthesized seven novel compounds with a pyrano[3,4-b] indole core structure. We evaluated the eEF2K inhibitory activity of seven of these novel compounds using in silico molecular modeling and in vitro studies in TNBC cell lines. We identified two novel compounds (EC1 and EC7) with significant in vitro activity in inhibiting eEF2K in TNBC cells. In conclusion, our studies indicate that pyrano[3,4-b] indole scaffold containing compounds demonstrate marked eEF2K inhibitory activity and they may be used as eEF2K inhibitors for the development of eEF2K-targeted therapeutics.

A new exploration toward adamantane derivatives as potential anti-MDR agents: Design, synthesis, antimicrobial, and radiosterilization activity as potential topoisomerase IV and DNA gyrase inhibitors

Developing novel antimicrobial agents has become a necessitate due to the increasing rate of microbial resistance to antibiotics. All the newly adamantane derivatives were evaluated for their antimicrobial activities against six MDR clinical pathogenic isolates. The results exhibited that 13 compounds have from potent to good activity. Among those, five derivatives (6, 7, 9, 14a, and 14b) displayed the potent activities against the different isolates tested (MIC < 0.25 µg/ml with bacteria and <8 µg/ml with fungi) compared with Ciprofloxacin (CIP) and Fluconazole (FCA). Additionally, the potent adamantanes showed bactericidal and fungicidal effects based on (MBCs and MFCs) and the time-kill assay. The most active adamantane derivatives 7 and 14b exhibited a synergistic effect of ΣFIC ≤ 0.5 with CIP and FCA against the bacterial and fungal isolates. Moreover, no antagonistic effect appeared for the tested derivatives. Additionally, the interaction of DNA gyrase and topoisomerase IV enzymes with the compounds 6, 7, 9, 14a, and 14b exhibited potent antimicrobial activity using in vitro biochemical assays and gel-based DNA-supercoiling inhibition method. The activity of DNA gyrase and topoisomerase IV enzymes showed inhibitory activity (IC₅₀ ) of 6.20 µM and 9.40 µM with compound 7 and 10.14 µM and 13.28 µM with compound 14b, respectively. Surprisingly, exposing compound 7 to gamma irradiation sterilized and increased its activity. Finally, the in-silico analysis predicted that the most active derivatives had good drug-likeness and safe properties. Besides, molecular docking and quantum chemical studies revealed several important interactions inside the active sites and showed the structural features necessary for activity.

Synthesis, characterization, thermal properties, antimicrobial evaluation, ADMET study, and molecular docking simulation of new mono Cu (II) and Zn (II) complexes with 2-oxoindole derivatives

One of the interesting research fields is developing and assessing novel metal-containing medications. A new isatin-3-thiosemicarbazone derivative 4 was synthesized by two different methods based on hydrazone derivatives 2 and 3. Additionally, the chelation of thiosemicarbazone with copper (II) and zinc (II) forms a monobasic tridentate (ONS) complex with two five-member rings and a tetrahedral geometry structure. The structure of synthesized complexes was characterized using elemental analysis, FT-IR, mass spectra, and ¹H/¹³C NMR. Thermogravimetric analysis revealed the upgrading of the thermal stability of metal complexes compared to their thiosemicarbazone ligand. The stoichiometric ratio of the coordination confirmed the formation of 1:1 (M: L) stoichiometry. In vitro antimicrobial activity was screened against two gram-positive, two gram-negative, and one fungal strain. Both ligand 4 and Zn complex 6 displayed high antimicrobial activity compared with copper complex 5 based on the zone of inhibition. Further, MIC and MBC were determined for both zinc and ligand. The zinc complex 6 displayed excellent antimicrobial activity with (MIC = 3.9-27.77 μg/mL) against bacterial strains and (MIC = 7.81 μg/mL) against C. albicans, as well as exhibited MBC values ranging between (MBC = 6.51-45.58 μg/mL) and (MFC = 13.58 μg/mL), respectively, and demonstrated bactericidal and fungicidal behavior. The in-silico ADMET study for ligand and two complexes were determined and showed non-AMES toxicity, non-carcinogenic, and obey the rule of five. A comparative docking study provided more insight into the binding mechanisms and suggested that antimicrobial activity may be due to inhibition of different targets.

Target-based anticancer indole derivatives and insight into structure‒activity relationship: A mechanistic review update (2018‒2021)

Cancer, which is the uncontrolled growth of cells, is the second leading cause of death after heart disease. Targeting drugs, especially to specific genes and proteins involved in growth and survival of cancer cells, is the prime need of research world-wide. Indole moiety, which is a combination of aromatic-heterocyclic compounds, is a constructive scaffold for the development of novel leads. Owing to its bioavailability, high unique chemical properties and significant pharmacological behaviours, indole is considered as the most inquisitive scaffold for anticancer drug research. This is illustrated by the fact that the U.S. Food and Drug Administration (FDA) has recently approved several indole-based anticancer agents such as panobinostat, alectinib, sunitinib, osimertinib, anlotinib and nintedanib for clinical use. Furthermore, hundreds of studies on the synthesis and activity of the indole ring have been published in the last three years. Taking into account the facts stated above, we have presented the most recent advances in medicinal chemistry of indole derivatives, encompassing hot articles published between 2018 and 2021 in anticancer drug research. The recent advances made towards the synthesis of promising indole-based anticancer compounds that may act via various targets such as topoisomerase, tubulin, apoptosis, aromatase, kinases, etc., have been discussed. This review also summarizes some of the recent efficient green chemical synthesis for indole rings using various catalysts for the period during 2018–2021. The review also covers the synthesis, structure‒activity relationship, and mechanism by which these leads have demonstrated improved and promising anticancer activity. Indole molecules under clinical and preclinical stages are classified into groups based on their cancer targets and presented in tabular form, along with their mechanism of action. The goal of this review article is to point the way for medicinal chemists to design and develop effective indole-based anticancer agents.

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.

Elhagali G, A. Eyada H, S. Aboul-Magd D, Ragab A. In Vitro Antimicrobial Evaluation, Single-Point Resistance Study, and Radiosterilization of Novel Pyrazole Incorporating Thiazol-4-one/Thiophene Derivatives as Dual DNA Gyrase and DHFR Inhibitors against MDR Pathogens

A series of thiazol-4-one/thiophene-bearing pyrazole derivatives as pharmacologically attractive cores were initially synthesized using a hybridization approach. All structures were confirmed using spectra analysis techniques (IR, ¹H NMR, and ¹³C NMR). In vitro antimicrobial activities, including the minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and time-kill assay, were evaluated for the most active derivatives 4a, 5a, 7b, 10, and 13. These derivatives were significantly active against the tested pathogens, with compound 7b as the most active derivative (MIC values range from 0.22 to 0.25 μg/mL). In the MBC and MFC, the active target pyrazole derivatives showed -cidal activities toward the pathogenic isolates. Further, the inhibition of biofilm formation of Staphylococcus aureus and Staphylococcus epidermidis was also carried out. Additionally, these derivatives displayed significant antibiofilm potential with a superior % reduction in the biofilm formation compared with Ciprofloxacin. The target derivatives behaved synergistically with Ciprofloxacin and Ketoconazole, reducing their MICs. Hemolytic results revealed that these derivatives were nontoxic with a significantly low hemolytic activity (%lysis range from 3.23 to 15.22%) compared with Triton X-100 and showed noncytotoxicity activity with IC₅₀ values > 60 μM. In addition, these derivatives proved to be active DNA gyrase and DHFR inhibitors with IC₅₀ ranging between 12.27-31.64 and 0.52-2.67 μM, respectively. Furthermore, compound 7b showed bactericidal activity at different concentrations in the time-kill assay. Moreover, a gamma radiation dose of 10.0 kGy was efficient for sterilizing compound 7b and enhancing its antimicrobial activity. Finally, molecular docking simulation of the most promising derivatives exhibited good binding energy with different interactions.

Design, synthesis and in vitro evaluation of the hybrids of oxindolylidene and imidazothiazolotriazine as efficient antiproliferative agents

1,3-Diethyl-6-oxindolylidenetetrahydroimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-2,7-dione with 2-propyl substituent at the nitrogen atom of oxindole fragment (1d) was identified previously as a lead compound in an antiproliferative agent discovery effort based on oxindolylidene derivatives of...

The first example of unusual reversible nucleophilic addition to 2-(5-aryl-2-oxo-3H-pyrrol-3-ylidene)malononitriles – a new tool for the creation of thermosensitive molecular switches

A new thermochromic system based on an unusual nucleophilic addition to pyrrol-3-ylidenemalononitrile derivatives was discovered.

Development of novel indolin-2-one derivative incorporating thiazole moiety as DHFR and quorum sensing inhibitors: Synthesis, antimicrobial, and antibiofilm activities with molecular modelling study

Nowadays, it's imperative to develop novel antimicrobial agents active against both drug-sensitive and drug-resistant bacterial infections with favorable profiles as high efficacy, low toxicity, and short therapy duration. Accordingly, a series of new thiazolo-indolin-2-one derivatives were synthesized based on acid and base catalyzed condensation or reaction of thiosemicarbazone 8 with different electrophilic reagents. The structure of the new compounds was confirmed based on elemental analysis and spectral data. Based on the MIC results, the most active thiazolo-indoline derivatives 2, 4, 7a, and 12 exhibited promising antibacterial activity against gram-positive and gram-negative bacteria with weak to moderate antifungal activities. Surprisingly, the N-(thiazol-2-yl)benzenesulfonamide derivative 4 was found to be most active on antibiofilm activity against both S. aureus (ATCC 29213) with BIC₅₀ (1.95 ± 0.01 µg/mL), while 5-(2-oxoindolin-3-ylidene)-thiazol-4(5H)-one derivative 7a exhibited the strongest antibiofilm activity against P. aeruginosa pathogens with BIC₅₀ (3.9 ± 0.16 µg/mL). Further, the thiazole derivatives 2, 4 and 12 exhibited a significant inhibition activity against the fsr system in a dose-dependent manner without affecting bacterial growth. The target derivatives behaved synergistic and additively effect against MDR p. aeruginosa, and thiazole derivative 12 exhibited a high synergistic effect with most tested antibiotics except Cefepime with FIC value ranging between 0.249 and 1.0, reducing their MICs. Interestingly, the 3-(2-(4-thiazol-2-yl)hydrazono)indolin-2-one derivative 12 displayed the highest selectivity to DHFR inhibitory with IC₅₀ value 40.71 ± 1.86 nM superior to those of the reference Methotrexate. Finally, in silico molecular modeling simulation, some physicochemical properties and toxicity predictions were performed for the most active derivatives.

Design, synthesis, molecular modeling, and antimicrobial potential of novel 3-[(1H-pyrazol-3-yl)imino]indolin-2-one derivatives as DNA gyrase inhibitors

A series of 3-[(1H-pyrazol-3-yl)imino]indolin-2-one derivatives were designed using the molecular hybridization method, characterized using different spectroscopic techniques, and evaluated for their in vitro antimicrobial activity. Most of the target compounds demonstrated good to moderate antimicrobial activity compared with ciprofloxacin and fluconazole. Four compounds (8b, 9a, 9c, and 10a) showed encouraging results, with minimal inhibitory concentration (MIC) values (53.45-258.32 µM) comparable to those of norfloxacin (100.31-200.63 µM) and ciprofloxacin (48.33-96.68 µM). Noticeably, the four derivatives revealed excellent bactericidal and fungicidal activities, except for the bacteriostatic potential of compounds 8b and 9a against Escherichia coli and Staphylococcus aureus, respectively. The time-killing kinetic study against S. aureus confirmed the efficacy of these derivatives. Furthermore, two of the four promising derivatives, 9a and 10a, could prevent the formation of biofilms of S. aureus without affecting the bacterial growth at low concentrations. A combination study with seven commercial antibiotics against the multidrug-resistant bacterium P. aeruginosa showed a notable reduction in the antibiotic MIC values, represented mainly through a synergistic or additive effect. The enzymatic assay implied that the most active derivatives had inhibition potency against DNA gyrase comparable to that of ciprofloxacin. Molecular docking and density functional theory calculations were performed to explore the binding mode and study the reactivity of the promising compounds.

Synthesis, biological evaluation and molecular docking of new sulfonamide-based indolinone derivatives as multitargeted kinase inhibitors against leukemia

Series of novel sulfonamide-based 3-indolinones 3a-m and 4a-f were designed, synthesized and then their cytotoxic activity was evaluated against a panel of sixty cancer cell lines. This screening indicated that 4-(2-(5-fluoro-2-oxoindolin-3-ylidene)acetyl)phenyl benzenesulfonate (4f) possessed promising cytotoxicity against CCRF-CEM and SR leukemia cell lines with IC₅₀ values 6.84 and 2.97 µM, respectively. Further investigation of the leukemic cytotoxicity of compound 4f was carried out by performing PDGFRα, VEGFR2, Aurora A/B and FLT3 enzyme assays and CCRF-CEM and SR cell cycle analysis. These investigations showed that compound 4f exhibited pronounced dual inhibition of both kinases PDGFRα and Aurora A with potency of 24.15 and 11.83 nM, respectively. The in vitro results were supported by molecular docking studies in order to explore its binding affinity and its key amino acids interactions. This work represents compound 4f as a promising anticancer agent against leukemia.

Quantum mechanical, virtual screening, molecular docking, molecular dynamics, ADME and antimicrobial activity studies of some new indole-hydrazone derivatives as potent agents against E. faecalis

In this study, a new series of indole-5-carbaldehyde hydrazone derivative compounds were designed, synthesized, and their antimicrobial activities were determined by the microdilution method, and the in vitro cytotoxic effects on Beas-2b cell lines were investigated by MTT assay. When the activity results were examined, 5i12 showed promising activity against E. faecalis with MIC: 2 µg/mL compared to ampicillin, gentamicin, and vancomycin, although the antimicrobial activities of the indole derivatives were generally weaker than those of the standard drugs. Compounds showed no cytotoxic activity on the A549, MCF-7, and Beas-2b cell lines. Molecular docking studies were performed on 15 different proteins to understand the mechanism of 5i12's good antimicrobial action against E. faecalis, and it was concluded that the compounds interacted with FabH, not enough other protein structures. Molecular dynamics simulations were performed to investigate the protein-ligand stability of the most active compound against E. faecalis. The RMSD value of 5i12 varied between 0.02 and 0.16 nm during the MD simulation. The apoprotein peaked at 0.55 nm at the beginning of the simulation and stabilized below 0.5 nm. The theoretical ADME profiles of all compounds were calculated and found to comply with Lipinski and other limiting rules. In addition, some theoretical quantum parameters (HOMO-LUMO) of compounds, and both MEP analysis and geometric optimization analysis for 5i12 were calculated using the 6-311 G (d,p) base set and DFT/B3LYP theory, and the results were visualized. Communicated by Ramaswamy H. Sarma.

5-Substituted isatin thiosemicarbazones as inhibitors of tyrosinase: Insights of substituent effects

Seven isatin-thiosemicarbazone analogues bearing different substituents (R) attached at C-5 of the indoline ring, TSC-ISA-R (R = -H, -CH₃, -OCH₃, -OCF₃, -F, -Cl and -NO₂), were synthesized and evaluated as inhibitors of mushroom tyrosinase (TYR). The inhibitory behaviour and performance of TSC-ISA-R were investigated spectroscopically in relation to the substituent modifications through examining their inhibition against the diphenolase activity of TYR using L-DOPA as a substrate. The IC₅₀ values of TSC-ISA-R were determined to be in the range of 81-209 μM. The kinetic analysis showed that TSC-ISA-R were reversible and mixed type inhibitors. Three potential non-covalent interactions rather than complexation including the binding of TSC-ISA-R with free TYR, TYR-L-DOPA complex, and with substrate L-DOPA were found to be involved in the inhibition. The substituent modifications affected these interactions by varying the characters of the resulting TSC-ISA-R in different degrees. The thiosemicarbazido moiety of each TSC-ISA-R contributed predominantly to the inhibition, and the isatin moiety seemed to play a regulatory role in the binding of TSC-ISA-R to the target molecules. The results of theoretical calculations using density functional theory method indicated a different effect of -R on the electron distribution in HOMO of TSC-ISA-R. The LUMO-HOMO energy gap of TSC-ISA-R almost accords with the trend of their experimental inhibition potency.

Oxindole and its derivatives: A review on recent progress in biological activities

Oxindole has been shown to be a pharmacologically advantageous scaffold having many biological properties that are relevant to medicinal chemistry. The simplicity and widespread occurrence of this scaffold in plant-based alkaloids have further reinforced oxindole's merit in the domain of novel drug discovery. First extracted from Uncaria tomentosa, commonly the known as cat claw's plant which was found abundantly in the Amazon rainforest, molecules with the oxindole moiety have been shown to be common in a wide variety of compounds extracted from plant sources. The role of oxindole as a chemical scaffold for fabricating and designing biological drugs agents can be ascribed to its ability to be modified by a number of chemical groups to generate novel biological functions. This review is aimed at providing a description of the general chemistry based on existing corresponding structure-activity relationships (SARs) and compile all recent developmentary studies on oxindole-derived compounds as a successful pharmaceutical agent. A substantial group of oxindole derivatives are chiefly being tested as anticancer agents, however, a several oxindole derivatives have been shown to possesses antimicrobial, α-glucosidase inhibitory, antiviral, antileishmanial, antitubercular, antioxidative, tyrosinase inhibitory, PAK4 inhibitory, antirheumatoid arthritis and intraocular pressure reducing activities, to name a few. In this review we show the potential value of developing newer oxindole derivatives with an improved range of pharmacological implications as well as identifying drugs possessing oxindole core, that are showing and serving increased efficacy in clinical practice.

Recent studies of nitrogen containing heterocyclic compounds as novel antiviral agents: A review

N-heterocycles are important, not only because of their abundance, but above all because of their chemical, biological and technical significance. They play an important role in biological investigation such as anticancer, antiinflammatory, antibacterial, antiviral, anti-tumor, antidiabetic, etc. In this study, we focused on examining synthesized some 5- or 6-ring N-heterocyclic compounds that showed the antiviral activity in last 5 years, and investigation of these compounds structure-activity relationship studies. This review will be useful to scientists in research fields of organic synthesis, medicinal chemistry, and pharmacology.

Design, Synthesis, Anticancer Evaluation, Enzymatic Assays, and a Molecular Modeling Study of Novel Pyrazole-Indole Hybrids

The molecular hybridization concept has recently emerged as a powerful approach in drug discovery. A series of novel indole derivatives linked to the pyrazole moiety were designed and developed via a molecular hybridization protocol as antitumor agents. The target compounds (5a-j and 7a-e) were prepared by the reaction of 5-aminopyrazoles (1a-e) with N-substituted isatin (4a,b) and 1H-indole-3-carbaldehyde (6), respectively. All products were characterized via several analytical and spectroscopic techniques. Compounds (5a-j and 7a-e) were screened for their cytotoxicity activities in vitro against four human cancer types [human colorectal carcinoma (HCT-116), human breast adenocarcinoma (MCF-7), human liver carcinoma (HepG2), and human lung carcinoma (A549)] using the MTT assay. The obtained results showed that the newly synthesized compounds displayed good-to-excellent antitumor activity. For example, 5-((1H-indol-3-yl)methyleneamino)-N-phenyl-3-(phenylamino)-1H-pyrazole-4-carboxamide (7a) and 5-((1H-indol-3-yl)methyleneamino)-3-(phenylamino)-N-(4-methylphenyl)-1H-pyrazole-4-carboxamide (7b) provided excellent anticancer inhibition performance against the HepG2 cancer cell line with IC₅₀ values of 6.1 ± 1.9 and 7.9 ± 1.9 μM, respectively, compared to the standard reference drug, doxorubicin (IC₅₀ = 24.7 ± 3.2 μM). The two powerful anticancer compounds (7a and 7b) were further subjected to cell cycle analysis and apoptosis investigation in HepG2 using flow cytometry. We have also studied the enzymatic assay of these two compounds against some enzymes, namely, caspase-3, Bcl-2, Bax, and CDK-2. Interestingly, the molecular docking study revealed that compounds 7a and 7b could well embed in the active pocket of the CDK-2 enzyme via different interactions. Overall, the prepared pyrazole-indole hybrids (7a and 7b) can be proposed as strong anticancer candidate drugs against various cancer cell lines.

Development of adamantane scaffold containing 1,3,4-thiadiazole derivatives: Design, synthesis, anti-proliferative activity and molecular docking study targeting EGFR

A new series of 1,3,4-thiadiazolo-adamantane derivatives were synthesized through molecular hybridization approach, then used as starting material to synthesize chloro and cyano acetamide-thiadiazole derivatives 2, 3. The newly designed compounds 1-3 were treated with different reagents to design 5-adamantyl thiadiazole derivatives 4-17 and evaluate their in vitro anti-proliferative activity against three cancer cell lines (MCF-7, HepG-2 and A549). Doxorubicin was used as a positive control. The most promising compounds 5, 6, 10a, 10b, 14b, 14c, and 17 showed up-regulation for BAX and down-regulation of Bcl-2, these findings proved their role as hopeful apoptotic inducers. In addition, the inhibitory activity against both wild EGFR^WT and mutant EGFR^L858R-TK for these derivatives revealed that compounds 5, 14c, and 17 have IC₅₀ value ranging from 85 nM to 71.5 nM against wild EGFR^WT and 37.85-41.19 nM against the mutant type, Lapatinib was used as a reference standard with IC₅₀ values of 31.8 nM and 39.53 nM, respectively. The most potent derivatives were subjected to further evaluation against double mutant EGFR ^L858R/T790M and showed good IC₅₀ values between (0.27-0.78 nM) compared to Lapatinib (0.18 nM) and Erlotinib (0.21 nM). Among them, thiazolo-thiadiazole adamantane derivative 17 exhibited the strongest inhibitory activity to the EGFR. Molecular docking studies were performed inside the active site of EGFR (1M17), and binding energy scores ranged between (-19.19 to -22.07 Kcal/mol) compared to Erlotinib (-19.10 Kcal/mol). Furthermore, oral bioavailability beside some pharmacokinetics properties of these derivatives were also investigated in this research work.

Sulfaguanidine Hybrid with Some New Pyridine-2-One Derivatives: Design, Synthesis, and Antimicrobial Activity against Multidrug-Resistant Bacteria as Dual DNA Gyrase and DHFR Inhibitors

Herein, a series of novel hybrid sulfaguanidine moieties, bearing 2-cyanoacrylamide 2a-d, pyridine-2-one 3-10, and 2-imino-2H-chromene-3-carboxamide 11, 12 derivatives, were synthesized, and their structure confirmed by spectral data and elemental analysis. All the synthesized compounds showed moderate to good antimicrobial activity against eight pathogens. The most promising six derivatives, 2a, 2b, 2d, 3a, 8, and 11, revealed to be best in inhibiting bacterial and fungal growth, thus showing bactericidal and fungicidal activity. These derivatives exhibited moderate to potent inhibition against DNA gyrase and DHFR enzymes, with three derivatives 2d, 3a, and 2a demonstrating inhibition of DNA gyrase, with IC₅₀ values of 18.17-23.87 µM, and of DHFR, with IC₅₀ values of 4.33-5.54 µM; their potency is near to that of the positive controls. Further, the six derivatives exhibited immunomodulatory potential and three derivatives, 2d, 8, and 11, were selected for further study and displayed an increase in spleen and thymus weight and enhanced the activation of CD4⁺ and CD8⁺ T lymphocytes. Finally, molecular docking and some AMED studies were performed.

Recent investigations into synthesis and pharmacological activities of phenoxy acetamide and its derivatives (chalcone, indole and quinoline) as possible therapeutic candidates

Medicinal chemistry can rightfully be regarded as a cornerstone in the public health of our modern society that combines chemistry and pharmacology with the aim of designing and developing new pharmaceutical compounds. For this purpose, many chemical techniques as well as new computational chemistry applications are used to study the utilization of drugs and their biological effects. In the biological interface, medicinal chemistry constitutes a group of interdisciplinary sciences, as well as controlling its organic, physical and computational pillars. Therefore, medicinal chemists working to design an integrated and developing system that portends an era of novel and safe tailored drugs either by synthesizing new pharmaceuticals or to improving the processes by which existing pharmaceuticals are made. It includes researching the effects of synthetic, semi-synthetic and natural biologically active substances based on molecular interactions in terms of molecular structure with triggered functional groups or the specific physicochemical properties. The present work focuses on the literature survey of chemical diversity of phenoxy acetamide and its derivatives (Chalcone, Indole and Quinoline) in the molecular framework in order to get complete information regarding pharmacologically interesting compounds of widely different composition. From a biological and industrial point of view, this literature review may provide an opportunity for the chemists to design new derivatives of phenoxy acetamide and its derivatives that proved to be the successful agent in view of safety and efficacy to enhance life quality.