Oxindole-based intraocular pressure reducing agents

Melatonin and its bioisosteres as potential therapeutic agents for the treatment of retinopathy of prematurity

We conducted a study on the impact of intraperitoneal injections of melatonin and its three bioisosteres (compounds 1-3) on the development of oxygen-induced retinopathy in newborn rats during a 21-day experiment. It was demonstrated that melatonin and its analogues 1-3 effectively reduce the total protein concentration in the vitreous body of rat pups, decrease concentration of VEGF-A, and lower the level of oxidative stress (as indicated by normalization of antioxidant activity in the vitreous body). Melatonin and its analogues 1-3 equally normalize the level of VEGF-A. Analogues 1 and 2 even exceed melatonin in their ability to reduce protein influx into the vitreous body. However, analogue 2 had no effect on antioxidant activity, while analogues 1 and 3 caused a significant increase in this parameter, with analogue 3 even slightly exceeding melatonin. Thus, it can be concluded that analogues 1-3 are comparable to melatonin and can be utilized as potential therapeutic agents for the treatment of retinopathy of prematurity.

One-Pot, Five-Component Condensation Reaction of Isatin, Secondary Amines, Malononitrile, Alcohols, and Molecular Oxygen to Access 3-Functionalized 2-Oxindoles

An efficient five-component condensation reaction of isatin, malononitrile, secondary amines, alcohols, and molecular oxygen was discovered. The reaction was performed in a one-pot fashion, and it does not require any metal catalyst. It gives straightforward access to structurally diverse 2-oxo-3-aminoindoline-3-carboxylates in moderate yields (70-88%). The scope of the reaction was successfully demonstrated by synthesizing a series of 3-functionalized 2-oxindoles by varying the isatin, amine, and alcohol components.

The rational design of novel 5-amino-2-oxindole derivatives with antiglaucomic activity

Compounds with a 2-oxindole scaffold play an important role in organic synthesis and especially in the synthesis of bioactive organic compounds, therefore, the development of new methods for modifying this scaffold is a very interesting and urgent task. In the framework of this study, we have created a rational approach to the synthesis of 5-amino-substituted derivatives of 2-oxindole. The approach is characterized by good total yield and a small number of steps. One-stage modification of obtained 5-amino-2-oxindoles leads to compounds with promising antiglaucomic activity. The most active compound 7a reduce intraocular pressure by 24% in normotensive rabbits (18% for reference drug timolol).

Microwave-Assisted Synthesis of 3-Hydroxy-2-oxindoles and Pilot Evaluation of Their Antiglaucomic Activity

Glaucoma is a widespread neurodegenerative disease for which increased intraocular pressure (IOP) is a primary modifiable risk factor. Recently, we have observed that compounds with oxindole scaffolds are involved in the regulation of intraocular pressure and therefore have potential antiglaucomic activity. In this article, we present an efficient method for obtaining novel 2-oxindole derivatives via microwave-assisted (MW) decarboxylative condensation of substituted isatins with malonic and cyanoacetic acids. Various 3-hydroxy-2-oxindoles were synthesized using MW activation for 5–10 min with high yields (up to 98%). The influence of novel compounds applied in instillations on IOP was studied in vivo on normotensive rabbits. The lead compound was found to reduce the IOP by 5.6 Torr (ΔIOP for the widely used antiglaucomatousic drug timolol 3.5 Torr and for melatonin 2.7 Torr).

Synthesis of New 2,3-Dihydroindole Derivatives and Evaluation of Their Melatonin Receptor Binding Affinity

2,3-Dihydroindoles are promising agents for the synthesis of new compounds with neuroprotective and antioxidant properties. Usually, these compounds are obtained by direct reduction of the corresponding indoles containing acceptor groups in the indole ring for its activation. In this work, we propose a synthetic strategy to obtain new 2,3-dihydroindole derivatives from the corresponding polyfunctional 2-oxindoles. Three methods were proposed for reduction of functional groups in the 2-oxindole and 2-chloroindole molecules using various boron hydrides. The possibility of chemoselective reduction of the nitrile group in the presence of an amide was shown. The proposed synthetic strategy can be used, for example, for the synthesis of new analogs of the endogenous hormone melatonin and other compounds with neuroprotective properties.

Preliminary Discovery of Small Molecule Inhibitors of Epidermal Growth Factor Receptor (EGFR) That Bind to the Extracellular Domain

The Epidermal Growth Factor Receptor (EGFR) is a transmembrane glycoprotein belonging to the protein kinase superfamily. It is composed of an extracellular domain, a transmembrane anchoring region and a cytoplasmic region endowed with tyrosine kinase activity. Genetic mutations of EGFR kinase cause higher activity thereby stimulating downstream signaling pathways that, in turn, impact transcription and cell cycle progression. Due to the involvement of mutant EGFR in tumors and inflammatory diseases, in the past decade, several EGFR inhibitory strategies have been extensively studied, either targeting the extracellular domain (through monoclonal antibodies) or the intracellular kinase domain (through ATP-mimic small molecules). Monoclonal antibodies impair the binding to growth factor, the receptor dimerization, and its activation, whereas small molecules block the intracellular catalytic activity. Herein, we describe the development of a novel small molecule, called DSF-102, that interacts with the extracellular domain of EGFR. When tested in vitro in KRAS mutant A549 cells, it impairs EGFR activity by exerting (i) dose-dependent toxicity effects; (ii) a negative regulation of ERK, MAPK p38 and AKT; and (iii) a modulation of the intracellular trafficking and lysosomal degradation of EGFR. Interestingly, DSF-102 exerts its EGFR inhibitory activity without showing interaction with the intracellular kinase domain. Taken together, these findings suggest that DSF-102 is a promising hit compound for the development of a novel class of anti-EGFR compounds, i.e., small molecules able to interact with the extracellular domain of EGFR and useful for overcoming the KRAS-driven resistance to TKI treatment.

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.

Synthesis and biological evaluation of 3-substituted 2-oxindole derivatives as new glycogen synthase kinase 3β inhibitors

Glycogen synthase kinase 3β (GSK-3β) is a widely investigated molecular target for numerous diseases including Alzheimer's disease, cancer, and diabetes mellitus. Inhibition of GSK-3β activity has become an attractive approach for treatment of diabetes and cancer. We report the discovery of novel GSK-3β inhibitors of 3-arylidene-2-oxindole scaffold with promising activity. The most potent compound 3a inhibits GSK-3β with IC₅₀ 4.19 nM. In a cell-based assay 3a shows no significant leucocyte toxicity at 10 µM and is moderately cytotoxic against A549 cells. Compound 3a demonstrated high antidiabetic efficacy in obese streptozotocin-treated rats improving glucose tolerance at a dose of 50 mg/kg body weight thus representing an interesting lead for further optimization.