Therapeutic investigations of novel indoxyl-based indolines: A drug target validation and Structure-Activity Relationship of angiotensin-converting enzyme inhibitors with cardiovascular regulation and thrombolytic potential

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.

Anticandidal Effect of New Imidazole Derivatives Over Aspartic Protease Inhibition

Candidiasis is one of the most serious microbial infections in the world. One of the main virulence factors for Candida albicans is the crucial secretion of aspartic proteases (Saps). Saps are hydrolytic enzymes that play a major role in many fungal pathophysiological processes as well as in many levels of the associations between the fungus and its host. In this work, we report on the synthesis, characterization, and anti-candida agent evaluation of a family of 13 imidazolidine-based aspartate protease inhibitors. In vitro and in silico enzyme inhibition studies have confirmed these compounds' ability to inhibit fungal aspartate protease. Based on the molecular mechanistic value scores from molecular docking and MD simulations, we selected the top compounds 5b (binding energy -13.90 kcal/mol) and 5m (binding energy -12.94 kcal/mol) from among 5a-l based on the molecular mechanistic value scores from molecular docking and MD simulations for use in in vitro validations. In the results, imidazolidine derivatives showed strong aspartic protease inhibition activity. In conclusion, compounds 5b and 5m were found as potent anti-candida agents and screened for further pre-clinical and clinical validations.

Development and Application of Indolines in Pharmaceuticals

In recent years, the incidence of cancer is high around the world, and the resistance of bacteria is increasing. To cope with the potentially adverse side effects of cancer chemotherapy and surgery, researchers are turning to the construction of new drug scaffolds. The indoline structure exists in a huge number of natural products, but drugs with indoline have only been formally studied in recent years. With the deepening of research, drugs containing indoline have played important roles in more disease treatment aspects, such as anti-tumor, anti-bacterial, anti-inflammatory and have been used as analgesics, to treat cardiovascular diseases and so on. The synthesis and pharmacological activity of indoline derivatives is summarized in this review in order to support the addition of the indoline component to the toolbox of medicinal chemists. This review focuses on the advantages of indoline compounds in development and synthesis of and for the use as anticancer drugs, antibacterial drugs, to treat cardiovascular diseases and as anti-inflammatory and analgesic drugs. Indoline structures are commonly found in natural and synthetic compounds with medicinal value and are now beginning to be exploited as the basic backbone of various drugs. As research continues, dihydroindoles and their derivatives will play a greater role in the medical field.

Pro- and Anti-Inflammatory Cytokine Expression Levels in Macrophages; An Approach to Develop Indazolpyridin-Methanones as a Novel Inflammation Medication

Background: Macrophages play a serious part in the instigation, upkeep, and resolution of inflammation. They are activated or deactivated during inflammation progression. Activation signals include cytokines (IF-γ, granulocyte-monocyte colony-stimulating factor (GM-CSF), and TNF-α), extracellular matrix proteins, and other chemical mediators. Activated macrophages are deactivated by anti-inflammatory cytokines (IL-10 and TGF-β (transforming growth factor-beta) and cytokine antagonists that are mainly produced by macrophages. Based on this, the present study aimed to develop novel (E)-Benzylidene-indazolpyridin methanones (Cpd-1-10) as effective anti-inflammatory agents by analyzing pro- and anti-inflammatory cytokine levels in macrophages.

Objectives: To determine the anti-inflammatory effect of indazolpyridin-methanones by examining pro- and anti-inflammatory interleukin levels in J77A.1 macrophages.

Methods: Expression of cytokines such as TNF-α, IL-1β, IL-6 and IL-10 serum levels measured by ELISA method. Anti-cancer and cytotoxicity studies were carried out by MTT assay. COX-2 seems to be associated with cancers and atypical developments in the duodenal tract. So, a competitive ELISA based COX-2 inhibition assay was done. To validate the inhibitory potentials and to get more insight into the interaction of COX-2 with Cpd1-10, molecular docking was performed.

Results: Briefly, the COX-2 inhibitory relative activity was found to be in between the range of 80-92% (Diclofenac showed 84%, IC50 0.95 µM).

Conclusion: Cytotoxicity effect of the compounds against breast cancer cell lines found excellent and an extended anticancer study ensured that these compounds are also alternative therapeutic agents against breast cancer. Among all the tested cancer cell lines, the anti-cancer effect on breast cancer was exceptional for the most active compounds Cpd5 and Cpd9.

Iron-Mediated Selective Sulfonylmethylation of Aniline Derivatives with p-Toluenesulfonylmethyl Isocyanide (TosMIC)

An iron-mediated highly selective C-H sulfonylmethylation of aniline derivatives with p-toluenesulfonylmethyl isocyanide in a mixture solvent of H₂O and PEG₄₀₀ under an Ar atmosphere has been realized. This transformation proceeds with operational convenience, use of earth-abundant metal catalyst and nontoxic media, broad substrate scope, and good functional group tolerance. The current methodology could be applied to the regioselective C-H sulfonylmethylation of indolines, tetrahydroquinolines, and tertiary anilines.

p-TSA.H2O mediated one-pot, multi-component synthesis of isatin derived imidazoles as dual-purpose drugs against inflammation and cancer

A novel one-pot multicomponent reaction was performed to synthesize different imidazole and benzotriazole (BTA) isatin-based medicinally important compounds using (p-TSA·H₂O) as an economical and operative acid catalyst. The yield of the products was found to be up to a maximum of 92% when using this catalyst. Antioxidant, anti-breast cancer and anti-inflammatory activities of these 13 isatin-based derivatives (named as 5a-m) were assessed. The inhibitory effects of these compounds were tested in vitro against cyclooxygenase-2 (COX-2, an enzyme responsible for inflammation) and phosphoinositide-3 kinase (PI3K, a key enzyme in breast cancer). "Among the 13 isatin-based Imidazole derivatives, five compounds (5a, 5d, 5f, 5 k and 5l) were found to exhibit anti-inflammatory as well as anti-cancer activity, which was validated using HRBC stabilization assay (to show anti-inflammatory activity) and cytotoxicity in MCF-7 (breast cancer cell line) to provide proof for anti-cancer property of the compounds". The molecular interactions between the two enzymes were probed using molecular docking. Structure-Activity Relationship (SAR) and ADMET prediction results were also useful to screen the most effective imidazole derivatives and to establish them as putative COX-2 inhibitors/anti-inflammatory drugs. These selected compounds which showed appreciable activity against COX-2 and PI3K are promising drug candidates for the treatment of breast cancer and inflammation which is often associated with breast cancer pathophysiology.

Anticancer Effects of Novel Tetrahydro-Dimethyl-Xanthene-Diones

BACKGROUND

The derivatives of xanthene are known to have promising anticancer properties, in comparison to xanthene itself.

OBJECTIVE

The object of our study was to develop few xanthene derivatives (a family of fifteen novel 3,4,6,7- tetrahydro-3,3-dimethyl-9-phenyl-2H-xanthene-1,8(5H, 9H)-diones encoded as 4a-4m), which were effectively prepared through regioselective synthesis approach, and to test their anticancer effects.

METHODS

A series of cell lines were used in this study, first to assess the cytotoxicity and then the drug efficacy of target compounds, consecutively. Prior to MTT assay, the compounds were analysed for their antioxidant properties, since oxidative stress is an important factor in the development of many cancer types. The anticancer properties of 4a-m have been assessed over in silico (molecular docking and ADMET assessments) and in vitro (MTT assay) methods.

RESULTS

Compounds 4h and 4i showed a relative percentage anticancer activity of 86.25±1.25 & 89.74±1.64 against BT474 (ER+HER2+), and 90.56±1.18 & 93.24±1.80 against MCF-7 (ER-HER2), respectively.

CONCLUSION

The animal model and pre-clinical studies for 4h and 4i should be performed in order to develop them as future anticancer agents.

Cp*Co(III)-Catalyzed C-7 C-C Coupling of Indolines with Aziridines: Merging C-H Activation and Ring Opening

A Cp*Co(III)-catalyzed directing group-assisted C7 C-C coupling of indolines with aziridines has been developed by merging C-H activation and ring opening. The use of cobalt catalyst, detection of a Co(III) intermediate, and late-stage removal of the directing group are important practical features.

Synthesis and discovery of triazolo-pyridazine-6-yl-substituted piperazines as effective anti-diabetic drugs; evaluated over dipeptidyl peptidase-4 inhibition mechanism and insulinotropic activities

A family of 12 triazolo-pyridazine-6-yl-substituted piperazines (5a-l) was synthesized and evaluated for their Dipeptidyl peptidase-4 (DPP-4) inhibition potentials in order to develop them as anti-diabetic medications. In the two-step synthesis process, 6-chloro-3-(m-tolyl)-[1,2,4]triazolo[4,3-b]pyridazine was synthesized with one-pot mode using pyridine, 3,6-dichloropyridazine 5-(3-methyl-phenyl)tetrazole in toluene. Conjugating corresponding 2° amines with 6-chloro-3-(m-tolyl)-[1,2,4]triazolo[4,3-b]pyridazine afforded the target triazolo-pyridazine-6-yl-substituted piperazines (5a-l). DPP-4 inhibition potential of these compounds was testified in silico and in nitro along with their insulinotropic activities in 832/13 INS-1 cells. H₂O₂ radical scavenging assay and MTT assay were conducted to assess the antioxidant and cytotoxicity of these compounds respectively. Molecular docking and ELISA based enzyme inhibition assay results revealed the strong inhibition potential of the target compounds. MTT assay results indicated a maximum dose of 2.5 nM (IC₅₀ 1.25 nM) could be used and above this level vital for the cells. Compounds 5a, 5c, 5g and 5i were found with excellent antioxidant and insulinotropic activity up to 99%.

Considerations for Docking of Selective Angiotensin-Converting Enzyme Inhibitors

The angiotensin-converting enzyme (ACE) is a two-domain dipeptidylcarboxypeptidase, which has a direct involvement in the control of blood pressure by performing the hydrolysis of angiotensin I to produce angiotensin II. At the same time, ACE hydrolyzes other substrates such as the vasodilator peptide bradykinin and the anti-inflammatory peptide N-acetyl-SDKP. In this sense, ACE inhibitors are bioactive substances with potential use as medicinal products for treatment or prevention of hypertension, heart failures, myocardial infarction, and other important diseases. This review examined the most recent literature reporting ACE inhibitors with the help of molecular modeling. The examples exposed here demonstrate that molecular modeling methods, including docking, molecular dynamics (MD) simulations, quantitative structure-activity relationship (QSAR), etc, are essential for a complete structural picture of the mode of action of ACE inhibitors, where molecular docking has a key role. Examples show that too many works identified ACE inhibitory activities of natural peptides and peptides obtained from hydrolysates. In addition, other works report non-peptide compounds extracted from natural sources and synthetic compounds. In all these cases, molecular docking was used to provide explanation of the chemical interactions between inhibitors and the ACE binding sites. For docking applications, most of the examples exposed here do not consider that: (i) ACE has two domains (nACE and cACE) with available X-ray structures, which are relevant for the design of selective inhibitors, and (ii) nACE and cACE binding sites have large dimensions, which leads to non-reliable solutions during docking calculations. In support of the solution of these problems, the structural information found in Protein Data Bank (PDB) was used to perform an interaction fingerprints (IFPs) analysis applied on both nACE and cACE domains. This analysis provides plots that identify the chemical interactions between ligands and both ACE binding sites, which can be used to guide docking experiments in the search of selective natural components or novel drugs. In addition, the use of hydrogen bond constraints in the S₂ and S₂′ subsites of nACE and cACE are suggested to guarantee that docking solutions are reliable.

Synthesis and discovery of pyrazolo-pyridine analogs as inflammation medications through pro- and anti-inflammatory cytokine and COX-2 inhibition assessments

This article briefs about the efforts taken to synthesis, characterize and develop (E)-5-methyl-2-phenyl-3-(thiophen-2-yl)-7-(thiophen-2-ylmethylene)-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridine and their analogs. In the two-step reaction, the first step is the synthesis of (3Z,5E)-1-methyl-3,5-bis(thiophen-2-ylmethylene)piperidin-4-one derivatives (3a-l) by stirring the mixture of 1-methylpiperidin-4-one and substituted thiophene-carbaldehydes in presence of methanol. In the second and final step, compounds 3a-l were refluxed with phenyl-hydrazine to achieve the target compounds (E)-5-methyl-2-phenyl-3-(thiophen-2-yl)-7-(thiophen-2-ylmethylene)-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridine and their analogs (5a-l) in good yield. These compounds were used to assess their inflammation regulation properties in macrophages by executing quantitative pro-inflammatory and anti-inflammatory proteins such as TNF-α, IL-1β, IL6, and IL-10 respectively. In silico and in vitro COX-2 inhibition studies helped to understand the molecular interaction or plausible mechanism during the inflammation regulation that showed by the compounds. In the results, among the 12-member family of pyrazolo-pyridines (5a-l), 5a, 5b, 5g, and 5j were showed excellent in silico binding affinity (1-10 nM), least binding energy (-12.45 to -14.27 kcal/mol) and in vitro COX-2 inhibition (relative percentage activity maximum 96.42%). Thus, these compounds perhaps to be future anti-inflammatory drugs.

Discovery and synthesis of 2-amino-1-methyl-1H-imidazol-4(5H)-ones as GPCR ligands; an approach to develop breast cancer drugs via GPCR associated PAR1 and PI3Kinase inhibition mechanism

Efforts were taken to synthesis and characterize 2-amino-1-methyl-1H-imidazole-4(5H)-one derivatives (4a-u) through a four-step reaction. The achieved compounds in remarkable yield have characterized through standard analytical techniques such as FTIR, LC-MS, NMR, HRMS, and elemental analysis. Present study mainly aimed to evaluate 4a-u as G protein-coupled receptors (GPCR). In the mechanism, stimulation of phosphoinositide 3-kinase (PI3K) and Akt (protein kinase B) is a general reaction activated by a series of membrane-bound receptors such as GPCR. Protease-activated receptor-1 (PAR1) is a subfamily of related GPCR, which triggered by the division of fragment of its extracellular domain. Therefore, molecular docking is done to ensure the inhibition of PAR1 and PI3Kinase. PI3Kinase is a chief enzyme in the development of breast cancer via the Akt/mTOR pathway. Thus, in vitro PI3Kinase inhibition and anti-breast cancer studies has also done to screen medicinally important compounds among (4a-u). Based on the best binding affinity, in vitro relative % activity and IC₅₀ values, compounds 4a, 4g, 4i, 4n, and 4u were screened for further preclinical studies in animal model evaluations.

Piperazine-azole-fluoroquinolone hybrids: Conventional and microwave irradiated synthesis, biological activity screening and molecular docking studies

A series of new 1,2,4-triazole and 1,3,4-oxadiazole derivatives was obtained via several steps sequential reactions of phenyl piperazine. Then, these compounds were converted to the corresponding fluoroquinolone hybrids via one pot three component Mannich reaction. All the reactions were examined under conventional and microwave mediated conditions, and optimum conditions were determined. The effect of different solvents and microwave power on microwave prompted reactions was investigated as well. All the newly synthesized compounds were characterized by FTIR, ¹H NMR, ¹³C NMR and EI MS spectral techniques. The antimicrobial activity, DNA gyrase and Topoisomerase IV inhibition potentials were performed. The results obtained showed that fluoroquinolone hybrids possess good antimicrobial activity. Moreover, Fluoroquinolone-azole-piperazine hybrids synthesized in the present study displayed excellent DNA gyrase inhibition. To unveil the interaction mode of compounds to receptor, a molecular docking study was performed. With an average least binding energy of -9.5 kcal/mol, all compounds were found to have remarkable inhibitory potentials against DNA gyrase (E. coli).

Naphthalene, a versatile platform in medicinal chemistry: Sky-high perspective

Naphthalene, a cytotoxic moiety, is an extensively explored aromatic conjugated system with applications in various pathophysiological conditions viz. anticancer, antimicrobial, anti-inflammatory, antiviral, antitubercular, antihypertensive, antidiabetic, anti-neurodegenerative, antipsychotic, anticonvulsant, antidepressant. Naphthalene epoxides and naphthoquinones are most reactive metabolites of naphthalene and are responsible for the covalent interaction with cysteine amino acid of cellular proteins for cytotoxic nature. Many naphthalene derived bioactive phytoconstituents are present in nature including podophyllotoxins (Etoposide, teniposide), bis-ANS 82, Rifampicin, Justiprocumin A, B, Patentiflorin A. The naphthalene-based molecules, viz. Naphyrone, tolnaftate, naftifine, nafcillin, terbinafine, propranolol, nabumetone, nafimidone, naproxen, duloxetine, lasofoxifene, bedaquiline etc. have also been approved by FDA and are being marketed as therapeutics. Thus, the naphthalene scaffold emerges as an important building block in drug discovery owing to its broad spectrum of biological activities through varying structural modifications. This review incorporates the pharmacological aspects of different types of chemically modified naphthalene-based molecules along with their activity profile. This compiled information may serve as a benchmark for the alteration of existing ligands to design novel potent molecules with lesser side effects.

An eco-friendly catalytic system for multicomponent, one-pot synthesis of novel spiro-chromeno indoline-triones and their anti-prostate cancer potentials evaluated via alkaline phosphatase inhibition mechanism

A green and efficient straightforward tactic for the one-pot regioselective synthesis of novel 10,10-dimethyl-9,10,11,11a-tetrahydro-6H-spiro[chromeno[4,3-b]chromene-7,3'-indoline]-2',6,8 (7aH) -triones (4a-n) in one-pot modus has been established using eco-friendly p-toluenesulphonic acid as catalyst. Among the solvents that were used for synthesis, 4a-n were suitably synthesized with maximum yield (90-98%) in water. We avoided column purification and the formed by-product in the process is environmental-friendly. Hence, this reaction may consider as an astonishing piece work in this study, why because, the reaction mechanism that depends on the nature of the group attached to the isatin ring nitrogen atom. The main advantage of this protocol includes short reaction time, good yield, easy to work-up, practical simplicity, high regioselectivity and reduced pollutant, cost and avoids tedious purification. These pharmaceutically important compounds (4a-n) were recognized for their alkaline phosphatase inhibition and prostate cancer medication capabilities. The selective activity relation between alkaline phosphatase and prostate cancer was unveiled through the interaction of 4a-n to Human alkaline phosphatase (PDB ID: 1EW2).