Synthesis, molecular modeling, selective aldose reductase inhibition and hypoglycemic activity of novel meglitinides.

In the present study, a novel generation of selective aldose reductase ALR2 inhibitors with significant hypoglycemic activities was designed and modulated based on rhodanine scaffold joined to an acetamide linker in between two lipophilic moieties. The synthesis of the novel compounds was accomplished throughout simple chemical pathways. Molecular docking was performed on B-cell membrane protein SUR1, aldehyde reductase ALR1 and aldose reductase ALR2 active sites. Compounds 10B, 11B, 12B, 15C, 16C, 26F and 27F displayed the highest hypoglycemic activities with 80.7, 85.2, 87, 82.3, 83.5, 81.4 and 85.3% reduction in blood glucose levels, respectively. They were more potent than the standard hypoglycemic agent repaglinide with 65.4% reduction in blood glucose level. Compounds 12B and 15C with IC50 0.29 and 0.35 µM were more potent than the standard ALR2 inhibitor epalrestat with IC50 0.40 µM. They were selective towards ALR2 over ALR1 134 and 116 folds, respectively. Molecular docking studies matched with the in-vitro and in-vivo results to elucidate the dual activities of both compounds 12B and 15C as potent antagonists for ALR2 over ALR1 and good agonists for the SUR1 protein.

Pharmacophore modeling, 3D-QSAR, synthesis, and anti-lung cancer evaluation of novel thieno[2,3-d][1,2,3]triazines targeting EGFR.

Two series of thieno[2,3-d][1,2,3]triazine derivatives were designed, synthesized, and biologically evaluated as potential epidermal growth factor receptor (EGFR) inhibitors targeting the non-small-cell lung cancer cell line H1299. Most of the synthesized compounds displayed IC50 values ranging from 25 to 58 nM against H1299, which are superior to that of gefitinib (40 µM). 3-(5,6,7,8-Tetrahydro-7H-cyclohexa[4:5]thieno[2,3-d]-1,2,3-triazin-4-ylamino)benzene-1,3-diamine (6b) achieved the highest cytotoxic activity against H1299 with an IC50 value of 25 nM; it had the ability to decrease the EGFR concentration in H1299 cells from 7.22 to 2.67 pg/ml. In vitro, the IC50 value of compound 6b was 0.33 nM against EGFR, which is superior to that of gefitinib at 1.9 nM and erlotinib at 4 nM. The three-dimensional quantitative structure-activity relationships and molecular modeling studies revealed comparable binding modes of compound 6b, gefitinib, and erlotinib in the EGFR active site. The in silico ADME (absorption, distribution, metabolism, and excretion) prediction parameters of this compound revealed promising pharmacokinetic and physicochemical properties. Moreover, DFT (density functional theory) calculations showed the high reactivity of compound 6b toward the EGFR compared with other compounds. The designed compound 6b might serve as an encouraging lead compound for the discovery of promising anti-lung cancer agents targeting EGFR.

Synthesis and molecular modeling of novel non-sulfonylureas as hypoglycemic agents and selective ALR2 inhibitors.

Novel non-sulfonylureas derivatives bearing an acetamide linker between a spirohydantoin scaffold and a phenyl ring were prepared and their hypoglycemic activity was estimated in vivo. Their abilities to discriminate in vitro between aldehyde reductase (ALR1) and aldose reductase (ALR2) were determined. The molecular docking and the in silico prediction studies were performed to rationalize the obtained biological results and to predict the physicochemical properties and drug-likeness scores of the new compounds. N-(2,4-Dichlorophenyl)-2-(2',4'-dioxospiro[fluorene-9,5'-imidazolidine]-3'-yl)acetamide (3e) displayed an 84% reduction in blood glucose level superior to that of repaglinide 66% and showed an IC50 value of 0.37 µM against ALR2 that is superior to that of sorbinil 3.14 µM. Compound (3e) was selective 96 fold towards ALR2 which is closely related to serious diabetic complications. Based on the identification of this hit candidate, a new generation of safe and effective antidiabetic agents could be designed.

Molecular modelling and synthesis of spiroimidazolidine-2,4-diones with dual activities as hypoglycemic agents and selective inhibitors of aldose reductase.

Novel derivatives of spiroimidazolidinedione were synthesized and evaluated as hypoglycemic agents through binding to sulfonylurea receptor 1 (SUR1) in pancreatic beta-cells. Their selectivity index was calculated against both aldehyde reductase (ALR1) and aldose reductase (ALR2). Aldehyde reductase is a key enzyme in the polyol pathway that is involved in the etiology of the secondary diabetic complications. All structures were confirmed by microanalysis and by IR, 1H NMR, 13C NMR and EI-MS spectroscopy. The investigated compounds were subjected to molecular docking and an in silico prediction study to determine their free energy of binding (ΔG) values and predict their physicochemical properties and drug-likeness scores. Compound 1'-(5-chlorothiophene-2-ylsulfonyl)spiro[cyclohexane-1,5'-imidazolidine]-2',4'-dione showed IC50 0.47 µM and 79% reduction in blood glucose level with a selectivity index 127 for ALR2.

Synthesis and EPR-spectroscopic characterization of the perchlorotriarylmethyl tricarboxylic acid radical (PTMTC) and its 13C labelled analogue (13C-PTMTC).

A hydrophilic tris(tetrachlorotriaryl)methyl (tetrachloro-TAM) radical labelled 50% with 13C at the central carbon atom was prepared. The mixture of isotopologue radicals was characterised by continuous wave and pulsed X-band electron paramagnetic spectroscopy (EPS). For the pharmaceutical and medical applications planned, the quantitative influence of oxygen, viscosity, temperature and pH on EPR line widths was studied in aqueous buffer, DMSO, water-methanol and water-glycerol mixtures. Under in vivo conditions, pH can be disregarded. There is a clear oxygen dependence of the width of the 12C isotopologue single EPR line in aqueous solutions while changes in rotational motion (viscosity) are observable only in the doublet lines of the central carbon of the 13C isotopologue. The tetrachloro-TAM proved to be very stable as a solid. Its thermal decay was determined quantitatively by thermal annealing. Towards ascorbic acid as a reducing agent and towards an oocyte cell extract it had a half-life of approx. 60 and 10 min. Thus for in vivo applications, 50% 13C tetrachloro-TAMs are suitable for selective and simultaneous oxygen and macroviscosity measurements in a formulation, e.g. nanocapsules.

Synthesis, Characterization, and Nanoencapsulation of Tetrathiatriarylmethyl and Tetrachlorotriarylmethyl (Trityl) Radical Derivatives­A Study To Advance Their Applicability as in Vivo EPR Oxygen Sensors.

Tissue oxygenation plays an important role in the pathophysiology of various diseases and is often a marker of prognosis and therapeutic response. EPR (ESR) is a suitable noninvasive oximetry technique. However, to reliably deploy soluble EPR probes as oxygen sensors in complex biological systems, there is still a need to investigate and improve their specificity, sensitivity, and stability. We reproducibly synthesized various derivatives of tetrathiatriarylmethyl and tetrachlorotriarylmethyl (trityl) radicals. Hydrophilic radicals were investigated in aqueous solution mimicking physiological conditions by, e.g., variation of viscosity and ionic strength. Their specificity was satisfactory, but the oxygen sensitivity was low. To enhance the capability of trityl radicals as oxygen sensors, encapsulation into oily core nanocapsules was performed. Thus, different lipophilic triesters were prepared and characterized in oily solution employing oils typically used in drug formulations, i.e., middle-chain triglycerides and isopropyl myristate. Our screening identified the deuterated ethyl ester of D-TAM (radical 13) to be suitable. It had an extremely narrow single EPR line under anoxic conditions and excellent oxygen sensitivity. After encapsulation, it retained its oxygen responsiveness and was protected against reduction by ascorbic acid. These biocompatible and highly sensitive nanosensors offer great potential for future EPR oximetry applications in preclinical research.

Synthesis, Docking, and DFT Studies on Novel Schiff Base Sulfonamide Analogues as Selective COX-1 Inhibitors with Anti-Platelet Aggregation Activity.

Selective COX-1 inhibitors are preferential therapeutic targets for platelet aggregation and clotting responses. In this study, we examined the selective COX-1-inhibitory activities of four newly synthesized compounds, 10-13, along with their abilities to inhibit platelet aggregation against ADP and collagen. The target compounds 10-13 were synthesized using the conventional method, sonication, and microwave-assisted methods. Microanalytical and spectral data were utilized to elucidate the structures of the new compounds 10-13. Additionally, a spectral NMR experiment [NOESY] was conducted to emphasize the configuration around the double bond of the imine group C=N. The obtained results revealed no observed correlation between any of the neighboring protons, suggesting that the configuration at the C=N double bond is E. Biological results revealed that all the screened compounds 10-13 might serve as selective COX-1 inhibitors. They showed IC50 values ranging from 0.71 µM to 4.82 µM against COX-1 and IC50 values ranging from 9.26 µM to 15.24 µM against COX-2. Their COX-1 selectivity indices ranged between 2.87 and 18.69. These compounds show promise as promising anti-platelet aggregation agents. They effectively prevented platelet aggregation induced by ADP with IC50 values ranging from 0.11 µM to 0.37 µM, surpassing the standard aspirin with an IC50 value of 0.49 µM. Additionally, they inhibited the platelet aggregation induced by collagen with IC50 values ranging from 0.12 µM to 1.03 µM, demonstrating superior efficacy compared to aspirin, which has an IC50 value of 0.51 µM. In silico molecular modeling was performed for all the target compounds within the active sites of COX-1 and COX-2 to rationalize their selective inhibitory activities towards COX-1. It was found that the binding interactions of the designed compounds within the COX-1 active site had remained unaffected by the presence of celecoxib. Molecular modeling and DFT calculations using the B3LYP/6-31+G (d,p) level were performed to study the stability of E-forms with respect to Z-forms for the investigated compounds. A strong correlation was observed between the experimental observations and the quantum chemical descriptors.

Development of a selective COX-2 inhibitor: from synthesis to enhanced efficacy via nano-formulation.

Non-steroidal anti-inflammatory drugs NSAIDs are widely used for managing various conditions including pain, inflammation, arthritis and many musculoskeletal disorders. NSAIDs exert their biological effects by inhibiting the cyclooxygenase (COX) enzyme, which has two main isoforms COX-1 and COX-2. The COX-2 isoform is believed to be directly related to inflammation. Based on structure-activity relationship (SAR) studies of known selective COX-2 inhibitors, our aim is to design and synthesize a novel series of 2-benzamido-N-(4-substituted phenyl)thiophene-3-carboxamide derivatives. These derivatives are intended to be selective COX-2 inhibitors through structural modification of diclofenac and celecoxib. The compound 2-benzamido-5-ethyl-N-(4-fluorophenyl)thiophene-3-carboxamide VIIa demonstrated selective COX-2 inhibition with an IC50 value of 0.29 µM and a selectivity index 67.24. This is compared to celecoxib, which has an IC50 value of 0.42 µM and a selectivity index 33.8. Molecular docking studies for compound VIIa displayed high binding affinity toward COX-2. Additionally, the suppression of protein denaturation with respect to albumin was performed as an indicative measure of the potential anti-inflammatory efficacy of the novel compounds. Compound VIIa showed potent anti-inflammatory activity with 93% inhibition and an IC50 value 0.54 µM. In comparison, celecoxib achieved 94% inhibition with an IC50 value 0.89 µM. Although molecule VIIa demonstrated significant in vitro anti-inflammatory activity, adhered to Lipinski's "five rules" (RO5) and exhibited promising drug-like properties, it showed indications of poor in vivo activity. This limitation is likely due to poor aqueous solubility, which impacts its bioavailability. This issue could be addressed by incorporating the drug in niosomal nanocarrier. Niosomes were prepared using the thin-film hydration technique. These niosomes exhibited a particle size of less than 200 nm, high entrapment efficiency, and an appropriate drug loading percentage. Transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) studies revealed that the niosomes were spherical and demonstrated compatibility of all of its components. The drug release study indicated that the pure drug had limited practicality for in vivo use. However, incorporating the drug into niosomes significantly improved its release profile, making it more suitable for practical use.

Synthesis, 3D-QSAR, and Molecular Modeling Studies of Triazole Bearing Compounds as a Promising Scaffold for Cyclooxygenase-2 Inhibition.

Targeting of cyclooxygenase-2 (COX-2) has emerged as a powerful tool for therapeutic intervention because the overexpression of this enzyme is synonymous with inflammation, cancer, and neurodegenerative diseases. Herein, a new series of 1,2,4-triazole Schiff bases scaffold with aryl and heteroaryl systems 9a-12d were designed, synthesized, structurally elucidated, and biologically evaluated as a potent COX-2 blocker. The rationale beyond the current study is to increase the molecule bulkiness allowing a selective binding to the unique hydrophobic pocket of COX-2. Among the triazole-thiazole hybrids, the one with the para-methoxy moiety linked to a phenyl ring 12d showed the highest In vitro selectivity by COX-2 inhibition assay (IC50 of 0.04 µM) and in situ anti-inflammatory activity when evaluated using the protein denaturation assay (IC50 of 0.88 µM) in comparison with commercially available selective COX-2 inhibitor, Celecoxib (IC50 of 0.05 µM). Towards the COX-2 selectivity, ligand-based three dimensional quantitative structures activity relationship (3D-QSAR) employing atomic-based and field-based approaches were performed and resulted in the necessity of triazole and thiazole/oxazole scaffolds for COX-2 blocking. Furthermore, the molecular modeling study indicated a high selectivity and promising affinity of our prepared compounds to COX-2, especially the hydrophobic pocket and the mouth of the active site holding hydrogen-bonding, hydrophobic, and electrostatic interactions. In Silico absorption, delivery, metabolism, and excretion (ADME) predictions showed that all the pharmacokinetic and physicochemical features are within the appropriate range for human use.

Discovery of Potent Dual EGFR/HER2 Inhibitors Based on Thiophene Scaffold Targeting H1299 Lung Cancer Cell Line.

Dual targeting of epidermal growth factor receptor (EGFR) and human EGFR-related receptor 2 (HER2) is a proven approach for the treatment of lung cancer. With the aim of discovering effective dual EGFR/HER2 inhibitors targeting non-small cell lung cancer cell line H1299, three series of thieno[2,3-d][1,2,3]triazine and acetamide derivatives were designed, synthesized, and biologically evaluated. The synthesized compounds displayed IC50 values ranging from 12 to 54 nM against H1299, which were superior to that of gefitinib (2) at 40 µM. Of the synthesized compounds, 2-(1H-pyrazolo[3,4-b]pyridin-3-ylamino)-N-(3-cyano4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)acetamide (21a) achieved the highest in vitro cytotoxic activity against H1299, with an IC50 value of 12.5 nM in situ, and 0.47 and 0.14 nM against EGFR and HER2, respectively, values comparable to the IC50 of the approved drug imatinib (1). Our synthesized compounds were promising, demonstrating high selectivity and affinity for EGFR/HER2, especially the hinge region forming a hydrophobic pocket, which was mediated by hydrogen bonding as well as hydrophobic and electrostatic interactions, as indicated by molecular modeling. Moreover, the designed compounds showed good affinity for T790M EGFR, one of the main mutants resulting in acquired drug resistance. Furthermore, both pharmacokinetic and physicochemical properties of the designed compounds were within the appropriate range for human usage as predicted by the in Silico ADME study. The designed compound (21a) might serve as an encouraging lead compound for the discovery of promising anti-lung cancer agents targeting EGFR/HER2.

EPR Oximetry Sensor-Developing a TAM Derivative for In Vivo Studies.

Oxygenation is one of the most important physiological parameters of biological systems. Low oxygen concentration (hypoxia) is associated with various pathophysiological processes in different organs. Hypoxia is of special importance in tumor therapy, causing poor response to treatment. Triaryl methyl (TAM) derivative radicals are commonly used in electron paramagnetic resonance (EPR) as sensors for quantitative spatial tissue oxygen mapping. They are also known as magnetic resonance imaging (MRI) contrast agents and fluorescence imaging compounds. We report the properties of the TAM radical tris(2,3,5,6-tetrachloro-4-carboxy-phenyl)methyl, (PTMTC), a potential multimodal (EPR/fluorescence) marker. PTMTC was spectrally analyzed using EPR and characterized by estimation of its sensitivity to the oxygen in liquid environment suitable for intravenous injection (1 mM PBS, pH = 7.4). Further, fluorescent emission of the radical was measured using the same solvent and its quantum yield was estimated. An in vitro cytotoxicity examination was conducted in two cancer cell lines, HT-29 (colorectal adenocarcinoma) and FaDu (squamous cell carcinoma) and followed by uptake studies. The stability of the radical in different solutions (PBS pH = 7.4, cell media used for HT-29 and FaDu cells culturing and cytotoxicity procedure, full rat blood and blood plasma) was determined. Finally, a primary toxicity test of PTMTC was carried out in mice. Results of spectral studies confirmed the multimodal properties of PTMTC. PTMTC was demonstrated to be not absorbed by cancer cells and did not interfere with luciferin-luciferase based assays. Also in vitro and in vivo tests showed that it was non-toxic and can be freely administrated till doses of 250 mg/kg BW via both i.v. and i.p. injections. This work illustrated that PTMTC is a perfect candidate for multimodal (EPR/fluorescence) contrast agent in preclinical studies.