Chloro-substituted pyridine squaramates as new DNase I inhibitors: Synthesis, structural characterization, in vitro evaluation and molecular docking studies.

Having continued our recent study on the synthesis and DNase I inhibition of several monosquaramides, two new chloro-substituted pyridine squaramates were synthesized and their structure was identified by X-ray. Their inhibitory properties towards deoxyribonuclease I (DNase I) and xanthine oxidase (XO) were evaluated in vitro. 3-(((6-Chloropyridin-3-yl)methyl)amino)-4-ethoxycyclobut-3-ene-1,2-dione (compound 3a) inhibited DNase I with an IC50 value of 43.82 ± 6.51 µM, thus standing out as one of the most potent small organic DNase I inhibitors tested to date. No cytotoxicity to human tumor cell lines (HL-60, MDA-MB-231 and MCF-7) was observed for the tested compounds. In order to investigate the drug-likeness of the squaramates, the ADME profile and pharmacokinetic properties were evaluated. Molecular docking was performed to reveal the binding mode of the studied compounds on DNase I.

Synthesis, Molecular Docking, and Biological Evaluation of Novel Anthranilic Acid Hybrid and Its Diamides as Antispasmodics.

The present article focuses on the synthesis and biological evaluation of a novel anthranilic acid hybrid and its diamides as antispasmodics. Methods: Due to the predicted in silico methods spasmolytic activity, we synthesized a hybrid molecule of anthranilic acid and 2-(3-chlorophenyl)ethylamine. The obtained hybrid was then applied in acylation with different acyl chlorides. Using in silico analysis, pharmacodynamic profiles of the compounds were predicted. A thorough biological evaluation of the compounds was conducted assessing their in vitro antimicrobial, cytotoxic, anti-inflammatory activity, and ex vivo spasmolytic activity. Density functional theory (DFT) calculation, including geometry optimization, molecular electrostatic potential (MEP) surface, and HOMO-LUMO analysis for the synthesized compounds was conducted using the B3LYP/6-311G(d,p) method to explore the electronic behavior, reactive regions, and stability and chemical reactivity of the compounds. Furthermore, molecular docking simulation along with viscosity measurement indicated that the newly synthesized compounds interact with DNA via groove binding mode. The obtained results from all the experiments demonstrate that the hybrid molecule and its diamides inherit spasmolytic, antimicrobial, and anti-inflammatory capabilities, making them excellent candidates for future medications.

Drug-Delivery Silver Nanoparticles: A New Perspective for Phenindione as an Anticoagulant.

Anticoagulants prevent the blood from developing the coagulation process, which is the primary cause of death in thromboembolic illnesses. Phenindione (PID) is a well-known anticoagulant that is rarely employed because it totally prevents coagulation, which can be a life-threatening complication. The goal of the current study is to synthesize drug-loaded Ag NPs to slow down the coagulation process. Methods: A rapid synthesis and stabilization of silver nanoparticles as drug-delivery systems for phenindione (PID) were applied for the first time. Results: Several methods are used to determine the size of the resulting Ag NPs. Additionally, the drug-release capabilities of Ag NPs were established. Density functional theory (DFT) calculations were performed for the first time to indicate the nature of the interaction between PID and nanostructures. DFT findings supported that galactose-loaded nanostructure could be a proper delivery system for phenindione. The drug-loaded Ag NPs were characterized in vitro for their antimicrobial, cytotoxic, and anticoagulant activities, and ex vivo for spasmolytic activity. The obtained data confirmed the drug-release experiments. Drug-loaded Ag NPs showed that prothrombin time (PT, sec) and activated partial thromboplastin time (APTT, sec) are approximately 1.5 times longer than the normal values, while PID itself stopped coagulation at all. This can make the PID-loaded Ag NPs better therapeutic anticoagulants. PID was compared to PID-loaded Ag NPs in antimicrobial, spasmolytic activity, and cytotoxicity. All the experiments confirmed the drug-release results.

Fused Triazinobenzimidazoles Bearing Heterocyclic Moiety: Synthesis, Structure Investigations, and In Silico and In Vitro Biological Activity.

[1,3,5]Triazino[1,2-a]benzimidazole-2-amines bearing heterocyclic moiety in 4-position were synthesized. The compounds were characterized by elemental analysis, IR, 1H-NMR, 13C-NMR, and HRMS spectroscopy. The molecular geometry and electron structure of these molecules were theoretically studied using density functional theory (DFT) methods. The molecular structure of the synthesized fused triazinobenzimidazole was confirmed to correspond to the 3,4-dihydrotriazinobenzimidazole structure through the analysis of spectroscopic NMR data and DFT calculations. The antinematodic activity was evaluated in vitro on isolated encapsulated muscle larvae (ML) of Trichinella spiralis. The results showed that the tested triazinobenzimidazoles exhibit significantly higher efficiency than the conventional drug used to treat trichinosis, albendazole, at a concentration of 50 µg/mL. The compound 3c substituted with a thiophen-2-yl moiety exhibited the highest anthelmintic activity, with a larvicidal effect of 58.41% at a concentration of 50 µg/mL after 24 h of incubation. Following closely behind, the pyrrole analog 3f demonstrated 49.90% effectiveness at the same concentration. The preliminary structure-anti-T. spiralis activity relationship (SAR) of the analogues in the series was discussed. The cytotoxicity of the benzimidazole derivatives against two normal fibroblast cells (3T3 and CCL-1) and two cancer human cell lines (MCF-7 breast cancer cells and chronic myeloid leukemia cells AR-230) was evaluated using the MTT-dye reduction assay. The screening results indicated that the compounds showed no cytotoxicity against the tested cell lines. An in silico study of the physicochemical and pharmacokinetic characteristics of the novel synthesized fused triazinobenzimidazoles showed that they were characterized by a significant degree of drug-likeness and optimal properties for anthelmintic agents.

In Silico, In Vitro, and Ex Vivo Biological Activity of Some Novel Mebeverine Precursors.

Irritable bowel syndrome (IBS) is a functional gastroenterological disorder with complex pathogenesis and multifaceted therapy approaches, aimed at alleviating clinical symptoms and improving the life quality of patients. Its treatment includes dietary changes and drugs from various pharmacological groups such as antidiarrheals, anticholinergics, serotonin receptor antagonists, targeting chloride ion channels, etc. The present article is focused on the synthesis and biological evaluation of some mebeverine precursors as potential antispasmodics. METHODS: In silico analysis aimed at predicting the pharmacodynamic profile of the compounds was performed. Based on these predictions, ex vivo bioelectrical activity (BEA) and immunohistochemical effects of the compounds were established. A thorough biological evaluation of the compounds was conducted assessing their in vitro antimicrobial and cytotoxic activity. RESULTS: All the newly synthesized compounds exerted drug-like properties, whereby 3-methyl-1-phenylbutan-2-amine 3 showed a significant change in BEA due to Ca2+ channel regulation, Ca2+ influx modulation, and a subsequent change in smooth muscle cell response. The immunohistochemical studies showed a good correlation with the obtained data on the BEA, defining amine 3 as a leader structure. No cytotoxicity to human malignant leukemic cell lines (LAMA-84, K-562) was observed for all tested compounds. CONCLUSION: Based on the experimental results, we outlined 3-methyl-1-phenylbutan-2-amine 3 as a potential effective choice for orally active long-term therapy of IBS.

Synthesis and DNase I Inhibitory Properties of New Squaramides.

Three new monosquaramides (3a-c) were synthesized, characterized by IR, NMR and X-ray, and evaluated for inhibitory activity against deoxyribonuclease I (DNase I) and xanthine oxidase (XO) in vitro. The target compounds inhibited DNase I with IC50 values below 100 µM, being at the same time more potent DNase I inhibitors than crystal violet, used as a positive control. 3-Ethoxy-4-((1-(pyridin-3-yl)propan-2-yl)amino)cyclobut-3-ene-1,2-dione (3c) stood out as the most potent compound, exhibiting a slightly better IC50 value (48.04 ± 7.98 µM) compared to the other two compounds. In order to analyze potential binding sites for the studied compounds with DNase I, a molecular docking study was performed. Compounds 3a-c are among the most potent small organic DNase I inhibitors tested to date.

Modulation Effect on Tubulin Polymerization, Cytotoxicity and Antioxidant Activity of 1H-Benzimidazole-2-Yl Hydrazones.

1H-benzimidazol-2-yl hydrazones with varying hydroxy and methoxy phenyl moieties were designed. Their effect on tubulin polymerization was evaluated in vitro on porcine tubulin. The compounds elongated the nucleation phase and slowed down the tubulin polymerization comparably to nocodazole. The possible binding modes of the hydrazones with tubulin were explored by molecular docking at the colchicine binding site. The anticancer activity was evaluated against human malignant cell lines MCF-7 and AR-230, as well as against normal fibroblast cells 3T3 and CCL-1. The compounds demonstrated a marked antineoplastic activity in low micromolar concentrations in both screened in vitro tumor models. The most active were the trimethoxy substituted derivative 1i and the positional isomers 1j and 1k, containing hydroxy and methoxy substituents: they showed IC50 similar to the reference podophyllotoxin in both tumor cell lines, accompanied with high selectivity towards the malignantly transformed cells. The compounds exerted moderate to high ability to scavenge peroxyl radicals and certain derivatives-1l containing metha-hydroxy and para-methoxy group, and 1b-e with di/trihydroxy phenyl moiety, revealed HORAC values high or comparable to those of well-known phenolic antioxidants. Thus the 1H-benisimidazol-2-yl hydrazones with hydroxy/methoxy phenyl fragments were recognized as new agents exhibiting promising combined antioxidant and antineoplastic action.

3'-Methyl-4-thio-1H-tetrahydropyranspiro-5'-hydantoin platinum complex as a novel potent anticancer agent and xanthine oxidase inhibitor.

In this study, a Pt(IV) complex with 3'-methyl-4-thio-1H-tetrahydropyranspiro-5'-hydantoin (complex 1) was synthesized. The structure was determined via elemental analyses, infrared, 1 H, and 13 C nuclear magnetic resonance techniques. Density functional theory calculations were applied to optimize the molecular geometry and to calculate structural parameters and vibrational frequencies. The cytotoxicity of the newly synthesized complex 1 was assessed against K-562 and REH cells and compared with the cytotoxic effects of the ligand (L) and its Pd(IV) complex (complex 2). Complex 1 exhibited a better cytotoxic activity (IC50 = 76.9 µM against K-562 and 15.6 µM against REH cells) than L and complex 2, which was closer to the cytotoxic effect of cisplatin (IC50 = 36.9 µM and 1.07 µM against K-562 and REH cells, respectively), as compared with the ligand and complex 2. L and its complexes 1 and 2 were evaluated for inhibitory activity against xanthine oxidase (XO) in vitro, as compared with allopurinol (IC50 = 1.70 µM). Complex 1 was shown as a potent XO inhibitor, with an IC50 value of 19.33 µM, and the binding mode with the enzyme was predicted by molecular docking. Its inhibitory activity against XO is a potential advantage that might result in improved profile and anticancer activity.

Synthesis, Crystal Structure and Biological Activity Screening of Novel N-(α-Bromoacyl)-α-amino Esters Containing Valyl Moiety.

Three novel N-(α-bromoacyl)-α-amino esters: methyl 2-(2-bromo-3-methylbutanamido)pentanoate (1), methyl 2-(2-bromo-3-methylbutanamido)-2-phenylacetate (2) and methyl 2-(2-bromo-3-methylbutanamido)-3-phenylpropanoate (3) were synthesized. Single crystal X-ray diffraction data are reported for compounds 1 and 2. The cytotoxicity, antiinflammatory and antibacterial activity of compounds 1-3 were investigated. Additionally, the physico-chemical properties of studied compounds were calculated and an in silico toxicological study of compounds 1-3 was performed. The low level of cytotoxicity and absence of antibacterial and anti-inflammatory activity of 1-3 in tested concentrations might be a beneficial prerequisite for their incorporation in prodrugs.

Effects on MC3T3-E1 Cells and In silico Toxicological Study of Two 6-(Propan-2-yl)-4-methyl-morpholine-2,5-diones.

Recently, we found that two cyclodidepsipeptides, 3,6-di-(propan-2-yl)-4-methyl-morpholine-2,5-dione (1) and 3-(2-methylpropyl)-6-(propan-2-yl)-4-methyl- morpholine-2,5-dione (2), are excellent inhibitors of xanthine oxidase. In order to obtain more information about the toxicological potential of compounds 1 and 2 on bone cells, the current study was designed to evaluate the effect of these compounds on viability and proliferation of MC3T3-E1 cells. Compound 1 showed neither cytotoxic nor stimulatory effect on cell viability, while compound 2 showed a slight stimulatory effect on cell viability. Both studied compounds showed slight stimulatory effects on proliferation of MC3T3-E1 cells, in a dose dependent manner. Additionally, an in silico toxicological study of compounds 1 and 2 was performed, and the results indicate that they have a good probability of safe biological intake.

Cyclodidepsipeptides with a promising scaffold in medicinal chemistry.

Among the large family of cyclodepsipeptides, the simplest members are the cyclodidepsipeptides which have an ester group and an amide group in the same six-membered ring. To point out the pharmacological potential of this class of compounds, the present article reviews structure, isolation, synthesis and biological properties of the known cyclodidepsipeptides. Synthesis of cyclodidepsipeptides is achieved by two general approaches--by initial formation of the amide bond, or initial formation of the ester bond; and subsequent intermolecular cyclization to cyclodidepsipeptide structure. It is closely related to the condensation and ring-closure strategies applied in the preparation of the larger members of the cyclodepsipeptide family. However, due to synthesis of the smaller heretocycles it allows for the use of more versatile building blocks. There are data on antimicrobial, antioxidant and immunomodulatory activities of cyclodidepsipeptides as well as their inhibitory activities toward α-glucosidase, acyl-CoA:cholesterol acyltransferase, xanthine oxidase and platelet aggregation. Because we have recently found that two 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones, as novel non-purine xanthine oxidase inhibitors, may give promise to be used in the treatment of gout, in this review we have included a study of molecular interactions of the selected cyclodidepsipeptides with xanthine oxidase using idTarget web server. Cyclodidepsipeptides showed promising pharmacological activities and meet all criteria for good solubility and permeability. However, further research of their medical application is necessary. In addition to this, the diversity of natural cyclodidepsipeptides, simplicity for synthesis and convenience for rational drug design indicate the cyclodidepsipeptide as promising scaffold in medicinal chemistry.

Two 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones as new non-purine xanthine oxidase inhibitors and anti-inflammatory agents.

Two cyclodidepsipeptides, 3-(2-methylpropyl)-6-(propan-2-yl)-4-methyl-morpholine-2,5-dione (1) and 3,6-di(propan-2-yl)-4-methyl-morpholine-2,5-dione (2), were evaluated for inhibitory activity against commercial enzyme xanthine oxidase (XO) in vitro and XO in rat liver homogenate as well as for anti-inflammatory response on human peripheral blood mononuclear cells (PBMCs). Both of cyclodidepsipeptides were excellent inhibitors of XO and significantly suppressed the nuclear factor of κB (NF-κB) activation. Allopurinol, a widely used XO inhibitor and drug to treat gout, relevated stronger inhibitory effect on rat liver XO activity than those of compounds 1 and 2. Molecular docking studies were performed to gain an insight into their binding modes with XO. The studied morpholine-diones derivatives exerting XO inhibition and anti-inflammatory effect may give a promise to be used in the treatment of gout and other excessive uric acid production or inflammatory conditions.

The effect of camphor and borneol on rat thymocyte viability and oxidative stress.

Camphor and borneol are wildly distributed in the essential oils of medicinal plants from various parts of the World. Our study has been carried out to evaluate the effect of these two bicyclic monoterpenes on rat thymocytes. Camphor and borneol at concentrations of 0.5 and 5 µg/mL did not induce significant toxicity on the immune system cells, while a significant increase of thymocyte viability was detected when cells were incubated with 50 µg/mL of camphor. A significant increase of cell viability was similarly detected when thymocytes were cultivated with borneol at concentrations of 0.5 and 5 µg/mL. The role of camphor and borneol in reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) disturbances in rat thymocytes as well as their potential mechanism(s) of action were also discussed.

6-(Propan-2-yl)-3-methyl-morpholine-2,5-dione, a novel cyclodidepsipeptide with modulatory effect on rat thymocytes.

A study has been carried out on the potential effect of a novel cyclodidepsipeptide, 6-(propan-2-yl)-3-methyl-morpholine-2,5-dione (PMMD), on rat thymocytes. Rat thymocytes were cultivated with increasing PMMD concentrations (0.1, 1, 10 µg/well), for 24h, and evaluated for proliferative activity, viability, reactive oxygen species and mitochondrial membrane potential. The higher PMMD concentrations inhibited thymocytes proliferative activity mainly through induction of oxidative stress and resulting cytotoxicity, without any mitochondrial membrane potential alterations in thymocytes. The obtained results are correlated with previously published data on effects of 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones on rat thymocytes. The presence of methyl group in position 4 or/and the length of alkyl chain in position 3 of 6-(propan-2-yl)-morpholine-2,5-dione core plays a role for the obtained differences in the biological response between PMMD and two previously tested 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones.

Stimulatory effect on rat thymocytes proliferation and antimicrobial activity of two 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones.

Recently we reported the identification and synthesis of cyclodidepsipeptides, 3,6-di(propan-2-yl)-4-methyl-morpholine-2,5-dione (PPM) and 3-(2-methylpropyl)-6-(propan-2-yl)-4-methyl-morpholine-2,5-dione (BPM), as potential precursors of enniatin B in Fusarium sporotrichioides. No data concerning biological activity of PPM and BPM have hitherto been published. The possible immunomodulatory effect and antimicrobial activity of PPM and BPM were investigated in this study, due to well known biological activities of enniatin B. The cytotoxicity effect of PPM and BPM on rat thymocytes demonstrated that increasing concentrations (0.1, 1, 10 µg/well) of PPM and BPM to cell culture, showed no significant effect on thymocytes toxicity. Simultaneously, incubation with studied cyclodidepsipeptides did not result with decreased mitochondrial membrane potential. Further, thymocytes exposure to increasing concentration of PPM and BPM was not able to induce significant reactive oxygen species (ROS) production in rat thymocytes. PPM and BPM administrations to cell culture in concentrations of 0.1 and 1 µg/well resulted with no significant increase of proliferative activity. However, significantly increased proliferative activity was detected with 10 µg of PPM (p<0.001) and BPM (p<0.05), as compared to their respective controls. The in vitro antimicrobial activity of PPM and BPM was tested against two Gram-positive and three Gram-negative bacteria. The results indicated that MIC values against tested strains ranged between 2.00 and 25.00 mg/ml. PPM showed much better activity against all tested bacteria in comparison with BPM. PPM was equally effective against both Gram-positive and Gram-negative bacteria, at the dose of 2.00 mg/ml.

In Vitro Antioxidant Activity of Two 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones.

In vitro antioxidant activity of two cyclodidepsipeptides, 3-(2-methylpropyl)-6-(propan-2-yl)-4-methyl-morpholine-2,5-dione and 3,6-di(propan-2-yl)-4-methyl-morpholine-2,5-dione, was investigated. Our data indicate moderate antioxidant potentials of the two studied cyclodepsipeptides. A high correlation between 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging capacity and total reducing power were found. According to the density functional theory (DFT) calculations, the most probable mechanism of antioxidant action is hydrogen atom abstraction from the activated C-H group at 3-position in the morpholinedione ring. To the best of our knowledge this is the first report about the antioxidant properties of morpholine-2,5-diones derivatives.