Isatin Nucleus Research Articles

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 ± 0.97µM) 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.

4a′-Hydroxy-3′,3′,5,6′,6′,7-hexamethyl-3′,4′,4a′,6′,7′,9a′-hexahydrospiro[indole-3,9′-xanthene]-1′,2,8′(1H,2′H,5′H)-trione

Pseudo-multicomponent reactions (Pseudo-MCRs) have led to a variety of compounds with interesting biological properties, especially desirable in the pharmaceutical industry. The isatin nucleus could be considered a privileged scaffold for the design of biologically active substances. Dimedone is an interesting and versatile molecule for most organic transformations, especially one-pot and multicomponent reactions. Xanthene derivatives are still an attractive research field for both academia investigations and industry. In this investigation, a simple and efficient tandem Knoevenagel–Michael protocol with subsequent cyclization for the synthesis of the previously unknown 4a′-hydroxy-3′,3′,5,6′,6′,7-hexamethyl-3′,4′,4a′,6′,7′,9a′-hexahydrospiro[indole-3,9′-xanthene]-1′,2,8′(1H,2′H,5′H)-trione was elaborated. The suggested method is based on the pseudo-MCR of 5,7-dimethylisatin and dimedone. The structure of the earlier unknown compound was proven using 1H, 13C-NMR, and IR spectroscopy, mass spectrometry, and elemental analysis. To compare the developed protocol with the existing ones, unsubstituted spiro[indole-3,9′-xanthene] was synthesized. Its structure has been proven using two-dimensional (2D) NMR spectroscopy techniques.

Design, Synthesis and Biological Assessment of Rhodanine-Linked Benzenesulfonamide Derivatives as Selective and Potent Human Carbonic Anhydrase Inhibitors.

A novel series of twenty-five rhodamine-linked benzenesulfonamide derivatives (7a-u and 9a-d) were synthesized and screened for their inhibitory action against four physiologically relevant human (h) carbonic anhydrase (CA) isoforms, namely hCA I, hCA II, hCA IX, and hCA XII. All the synthesized molecules showed good to excellent inhibition against all the tested isoforms in the nanomolar range due to the presence of the sulfonamide as a zinc binding group. The target compounds were developed from indol-3-ylchalcone-linked benzenesulfonamide where the indol-3-ylchalcone moiety was replaced with rhodanine-linked aldehydes or isatins to improve the inhibition. Interestingly, the molecules were slightly more selective towards hCA IX and XII compared to hCA I and II. The most potent and efficient ones against hCA I were 7h (KI 22.4 nM) and 9d (KI 35.8 nM) compared to the standard drug AAZ (KI 250.0 nM), whereas in case of hCA II inhibition, the derivatives containing the isatin nucleus as a tail were preferred. Collectively, all compounds were endowed with better inhibition against hCA IX compared to AAZ (KI 25.8 nM) as well as strong potency against hCA XII. Finally, these newly synthesized molecules could be taken as potential leads for the development of isoform selective hCA IX and XII inhibitors.

Design, synthesis and biological evaluation of isatin-benzotriazole hybrids as new class of anti-Candida agents

A novel series of triazole tethered isatin-benzotriazole hybrids has been designed as potential antifungal agents against Candida strains. Hybrid molecules were synthesised via click chemistry approach and characterized by NMR and Mass spectroscopic techniques. Among the synthesized hybrids, AS14 showed most potent activity against fluconazole resistant Candida albicans with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 3.9 and 7.8 µM respectively. Structure-activity relationship studies revealed that fluoro (F) substitution on 5th position of isatin nucleus and four carbon distance between isatin and triazole moiety is most tolerable for inhibitory potential of the structure against Candida albicans. AS14 was also capable to inhibit biofilm formation and ergosterol synthesis in Candida albicans. Molecular docking studies revealed the favourable binding pattern of AS14 with sterol 14α-demethylase enzyme (CYP51) of Candida albicans. Furthermore, molecular dynamic studies suggested the stability of enzyme-hybrid complex. Overall study suggested that hybrid AS14 can act as an effective hit lead for further development of potent and safer antifungal agents for tackling Candida infections.

Design, synthesis, and biological evaluation of isatin-indole-3-carboxaldehyde hybrids as a new class of xanthine oxidase inhibitors.

A novel series of triazole-linked isatin-indole-3-carboxaldehyde hybrids based on the febuxostat skeleton and its binding site interactions were rationally designed and synthesized as potential xanthine oxidase inhibitors. Among the synthesized hybrids, A19 showed the most potent xanthine oxidase inhibition (IC50 = 0.37 µM) with the mixed-type inhibitory scenario. Structure-activity relationship studies revealed that methoxy (OCH3 ) substitution on position 5 of the isatin nucleus and a two-carbon distance between isatin and the triazole moiety is most tolerable for the inhibitory potential. Various binding interactions of A19 with the binding site of xanthine oxidase are also streamlined by molecular docking studies, which showcase the favorable binding pattern for xanthine oxidase inhibition by the hybrid. Furthermore, molecular dynamic studies were performed that suggest the stability of the enzyme-hybrid complex. Overall, the study suggests that hybrid A19 can act as an effective hit lead for further development of potent xanthine oxidase inhibitors.

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.

A REVIEW ON ISATIN AND ITS DERIVATIVES: SYNTHESIS, REACTIONS AND APPLICATIONS

Isatin, also known as 1H-Indole-2, 3-Dione, is an eight-carbon containing endogenous compound found in nature. Erdmann and Laurent synthesized isatin in 1840, before it was discovered in nature. It is versatile and distributed in tissues and body fluids. Isatins have also been detected in mammalian tissue, and their function as a biochemical process modulator has been the focus of many debates. The isatin moiety also shows some important chemical reactions such as oxidation, N-Acylation, Friedel-Crafts reaction, N-Halogenation, etc. Antitumor, antimicrobial, anti-inflammatory, anticonvulsant, antiviral, anti-HIV, antioxidant, and CNS depressant functions are all possessed by simple isatin nucleus. Substituted derivatives of this compound also have these properties. The isatin derivatives are effective inhibitors of the urease and α-glucosidase enzymes. This review provides a brief overview on the some commonly used procedures to synthesize the isatin moiety and its derivatives, its physical properties, reactions and biological activities.

A REVIEW ON ISATIN AND ITS DERIVATIVES: SYNTHESIS, REACTIONS AND APPLICATIONS

Isatin, also known as 1H-Indole-2, 3-Dione, is an eight-carbon containing endogenous compound found in nature. Erdmann and Laurent synthesized isatin in 1840, before it was discovered in nature. It is versatile and distributed in tissues and body fluids. Isatins have also been detected in mammalian tissue, and their function as a biochemical process modulator has been the focus of many debates. The isatin moiety also shows some important chemical reactions such as oxidation, N-Acylation, Friedel-Crafts reaction, N-Halogenation, etc. Antitumor, antimicrobial, anti-inflammatory, anticonvulsant, antiviral, anti-HIV, antioxidant, and CNS depressant functions are all possessed by simple isatin nucleus. Substituted derivatives of this compound also have these properties. The isatin derivatives are effective inhibitors of the urease and α-glucosidase enzymes. This review provides a brief overview on the some commonly used procedures to synthesize the isatin moiety and its derivatives, its physical properties, reactions and biological activities.

Isatin Hybrids and Their Pharmacological Investigations.

Hybridization is an important strategy to design molecules that can be effectively used to treat fatal diseases known to mankind. Molecular hybrids and their pharmacological investigations aided in discovering several potent isatin (Indole 2, 3 dione) derivatives with anti-HIV, antimalarial, antitubercular, antibacterial, and anticancer activities. Indole-2,3-dione and their derivatives have diverse pharmacological properties and have a prominent role in the discovery of new drugs. To understand the various approaches for designing new molecules based on isatin nucleus analysis of various pharmacophore hybrids, spacers/linkers between pharmacophores and isatin for hybridization and their biological activities are important. This review discusses the progress in developing isatin hybrids as biologically effective agents and their crucial aspects of design and structure-activity relationships.

Computational Studies of bis-2-Oxoindoline Succinohydrazides and their In Vitro Cytotoxicity.

The discovery of clinically relevant EGFR inhibitors for cancer therapy has proven to be a challenging task. To identify novel and potent EGFR inhibitors, the quantitative structure-activity relationship (QSAR) and molecular docking approach became a very useful and largely widespread technique for drug design. We performed the in vitro cytotoxic activity on HEPG-2 cell line and earlier on MCF-7 and A 549 by using MTT assay method. The development of 3D QSAR model of N1,N4-bis(2-oxoindolin-3- ylidene) succinohydrazides using the stepwise-backward variable methods to generate Multiple Linear Regression method elucidates the structural properties required for EGFR inhibitory activity and also perform the Molecular Docking studies on EGFR (PDB ID:1M17). Further, we analysed for Lipinski's rule of five to evaluate the drug-likeness and established in silico ADMET properties. The resulting cytotoxicity (IC50) values ranged from 9.34 to 100 μM and compared with cisplatin as a standard. Among the series of compounds, 6j showed good cytotoxic activity on HEPG-2 cell line with 9.34 μM, IC50 value. Most of the evaluated compounds showed good antitumor activity on HEPG-2 than MCF-7and A549. The developed 3D QSAR Multiple Linear Regression models are statistically significant with non-cross-validated correlation coefficient r2 = 0.9977, cross-validated correlation coefficient q2 = 0.902 and predicted_r2 = 0.9205. Molecular docking studies on EGFR (PDB ID: 1M17) results, compounds 6d, 6j and 6l showed good dock/PLP scores i.e. -81.28, -73.98 and -75.37, respectively, by interacting with Leu-694, Val-702 and Gly-772 amino acids via hydrophobic and hydrogen bonds with Asn818 and Met- 769. Further, we analysed drug-likeness and established in silico ADMET properties. The results of 3D QSAR studies suggest that the electrostatic and steric descriptors influence the cytotoxic activity of succinohydrazides. From the molecular docking studies, it is evident that hydrophobic, hydrogen and Van Der Waal's interactions determine binding affinities. In addition to this, druglikeness and ADMET properties were analysed. It is evident that there is a correlation between the QSAR and docking results. Compound 6j was found to be too lipophilic due to its dihalo substitution on isatin nucleus, and can act as a lead molecule for further and useful future development of new EGFR Inhibitors.

Synthesis, anti-proliferative activity, theoretical and 1H NMR experimental studies of Morita-Baylis-Hillman adducts from isatin derivatives.

Quaternary or spirocyclic 3-substituted-3-hydroxy-2-oxindole is considered a privileged scaffold. In other words, it is a molecular core present on several compounds with a wide spectrum of biological activities. Among its precursors, activated ketones (isatin nucleus) can be used as interesting starting points to Morita-Baylis-Hillman adducts derivatives, a class of compounds with good cytotoxic potential. In this paper, we present the synthesis, anti-proliferative activity against lung cancer cell line and a theoretical conformational study of 21 of Morita-Baylis-Hillman adducts from isatin derivatives, by DFT quantum chemical calculations, followed by a SAR and QSAR analysis. Besides, an efficient synthetic protocol and good biological activity profile were highlighted interesting observations about 1H NMR experimental spectra, molecular modeling results and crystallographic data available.

Investigating the Anticancer Activity of Isatin/Dihydropyrazole Hybrids.

A series of isatin-dihydropyrazole hybrids have been synthesized in order to assess their potential as anticancer agents. In particular, 12 compounds were evaluated for their antiproliferative activity toward A549, IGR39, U87, MDA-MB-231, MCF-7, BT474, BxPC-3, SKOV-3, and H1299 cell lines, and human foreskin fibroblasts. Four compounds exhibited interesting antiproliferative activity and were further examined to determine their EC50 values toward a panel of selected tumor cell lines. The best compounds were then investigated for their induced mechanism of cell death. Preliminary structure-activity relationship indicates that the presence of a substituent such as a chlorine atom or a methyl moiety in position 5 of the isatin nucleus is beneficial for the antitumor activity. EMAC4001 proved the most promising compound within the studied series with EC50 values ranging from 0.01 to 0.38 μM.

Imatinib derivatives as inhibitors of K562 cells in chronic myeloid leukemia

Imatinib was the first representative of the class of Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog (BCR-ABL) tyrosine kinase inhibitors used for the treatment of chronic myeloid leukemia. Second-generation and third-generation drugs have been introduced in this therapy, affording increased patient survival. However, all BCR-ABL tyrosine kinase inhibitors have been shown to induce resistance, necessitating a search for new therapeutic options. The sunitinib, another tyrosine kinase inhibitor used in the treatment of renal cell carcinoma and gastrointestinal stromal tumors is an isatin derivative. Isatin nucleus is highly versatile for the preparation of new substances, and several tyrosine kinase inhibitors examples have been obtained using it. This work aimed to design, synthesize, and biological evaluation of new compounds using the K562 cell line, which constitutively expresses the active BCR-ABL enzyme. Three new series of imatinib derivatives have been planned from the imatinib, and all have a phenylaminopyrimidine group as the main pharmacophore. Sunitinib was used as a structural prototype to planning the series 1 (8a–e) of hybrids between sunitinib and imatinib. Series 2 and 3 are 2-oxo-2-phenyacetamide and 2,2-difluoro-2-phenylacetamide derivatives, respectively. Isatins were used as the starting materials for all series. Compounds were synthesized using simple methodologies and were obtained in high purities. The compounds were tested against K562 cells, and four showed a reduction in cell viability, with EC50 values ranging from 0.37 to 2.02 μM, some of which are close to the imatinib standard (0.21 µM).

Utility of Isatin Semicarbazones in Mammary Carcinoma Cells - A Proof of Concept Study

Objective: The present study was aimed to determine cytotoxic and apoptotic activity of isatin semicarbazones against mammary carcinoma. Methodology: The preparation of these target compounds involved substitution at the third position of the isatin nucleus along with chemical modification at the nitrogen atom of the scaffold to obtain more potent derivatives. The synthesized analogs were characterized by recording their melting point and R f values along with IR, NMR and mass spectra. An antioxidant study and Cytotoxic Studies were performed by DPPH, Nitric oxide scavenging method and MTT assay methods. Results: The results revealed that all the test compounds (5a-5d) exhibited good anti oxidant activity. The synthesized compounds were then screened for in-vitro cytotoxicity by MTT cell proliferation assay method against breast cancer cell lines including MCF-7 and BT-549 with derivative 5a exhibiting maximum activity in both the cell lines. DNA fragmentation studies further indicated that 5a was involved in apoptotic process. Conclusion: Interestingly, it was observed that while all the synthesized compounds seemed active, 5a exhibited a superior ability to induce apoptosis. Key words: Anticancer, DNA fragmentation, Isatin, Mammary carcinoma, MTT assay, Antioxidant.

Isatin thiazoline hybrids as dual inhibitors of HIV-1 reverse transcriptase

A series of 3-3-{2-[2-3-methyl-4-phenyl-2,3-dihydro-1,3-thiazol-2-ylidene]hydrazin-1-ylidene-2,3-dihydro-1H-indol-2-one derivatives has been designed and synthesized to study their activity on both HIV-1 (Human Immunodeficiency Virus type 1) RT (Reverse Transcriptase) associated functions. These derivatives are analogs of previously reported series whose biological activity and mode of action have been investigated. In this work we investigated the influence of the introduction of a methyl group in the position 3 of the dihydrothiazole ring and of a chlorine atom in the position 5 of the isatin nucleus. The new synthesized compounds are active towards both DNA polymerase and ribonuclease H in the µM range. The nature of the aromatic group in the position 4 of the thiazole was relevant in determining the biological activity.

Synthesis and anticancer activity of new isatin-benzoic acid conjugates

A series of new isatin-benzoic acid conjugates (9a - n) were synthesized via conjugation of isatin (3a) and its derivatives (3b - d, 4, 5 and 6) with 4-amino-5 chloro-2-ethoxybenzoic acid or 4-amino-5-(ethylsulfonyl)-2- methoxybenzoic acid by using chloroacetyl chloride as a bifunctional linker. Compounds 3a - d were prepared by employing Sandmeyer reaction. Compounds 4, 5, and 6 were obtained from isatin (3a) via previously reported methods. Isatin-benzoic acid conjugates were synthesized by halomethylketo alkylation at N-1 position of the isatin nucleus. The newly synthesized compounds were characterized using IR, Mass, 1H NMR and 13C NMR spectral techniques. Anticancer activity of the synthesized compounds was evaluated againstMCF-7 (human breast cancer) and HeLa (human cervical cancer) cell lines by 3-(4,5-dimethylthiazol -2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay using vinblastin as a standard. The results showed compounds 9g and 9d to be more potent than the other compounds synthesized with IC50 values of 5.88 ± 0.88 & 6.57 ± 0.81 μM against MCF-7, and 8.34 ± 0.94 & 9.24 ± 1.06 μM against HeLa, respectively.Keywords: synthesis, isatin-benzoic acid conjugates, in vitro anticancer, human breast cancer cell line, human cervical cancer cell line

Schiff bases of indoline-2,3-dione (isatin) with potential antiproliferative activity

BackgroundCancer is one of the most dreaded diseases and it is a leading cause of mankind death worldwide. Recent reports documented a remarkable antiproliferative activity of isatin nucleus against various cancer cell lines. The current work describes the antiproliferative activity of Schiff bases of combinatorial mixtures of the isatin derivatives M1-M22 as well as the individual compounds 1-11(A-K) of these combinatorial mixtures.ResultsThe designed combinatorial library composed from eleven hydrazides A-K and eleven isatin derivatives 1-11 has been synthesized to formally generate 22 mixtures, M1-M22 of 121 Schiff bases, and their antiproliferative activity against K562 chronic myelogenous leukemia cells was evaluated. The indexed method of analysis of the prepared library was applied to elucidate the active components in the tested mixtures M1-M22. The predictions from the crossing procedure was validated through evaluation of the antiproliferative activity of individual compounds 1-11(A-K) of the library. Individual compounds 1-11(A-K) were also evaluated against the non-tumorigenic MCF-12A cell line to investigate their selectivity. A pharmacophore model was developed to further optimize the antiproliferative activity among this series of compounds.ConclusionsVariable antiproliferative activity was revealed with the investigated mixtures M1-M22 and the individual compounds 1-11(A-K). Most of the tested mixtures and several individual Schiff bases displayed high potency with IC50 values in the low micromolar range. A considerable selectivity of some individual compounds to the tumorigenic K562 cell line compared with the non-tumorigenic MCF-12A cell line was observed as indicated by their selectivity index (SI).

Design of potential reverse transcriptase inhibitor containing Isatin nucleus using molecular modeling studies

Two Dimensional (2D) and Three Dimensional (3D) Quantitative Structure–Activity Relationship (QSAR) studies were performed for correlating the chemical composition of Isatin analogues and their anti-HIV activity using Multiple Linear Regression (MLR) Analysis and k Nearest Neighbor Molecular Field Analysis (kNN MFA), respectively. New Chemical Entities (NCEs) were designed using results of QSAR studies. Binding affinities of designed NCEs were studied on Reverse Transcriptase enzyme using docking studies and their ADME properties were also predicted. Finally most promising compounds were selected from molecular modeling studies. Five compounds containing Isatin nucleus were synthesized and tested for their anti-HIV activity by performing Reverse Transcriptase Assay. Three compounds showed significant Reverse Transcriptase inhibiting activity compared to standard Navirapine. Structure–Activity Relationships were also discussed bases on obtained molecular modeling and experimental data.